Merge branch 'master' into nymkappa/scan-closed-channel-no-mempool

2023-05-11 11:04:19 -05:00
parent c675d1c498 17dd02ed4e
commit cb9d09a930
176 changed files with 8734 additions and 3415 deletions
--- a/backend/src/fixtures/mempool-config.template.json
+++ b/backend/src/fixtures/mempool-config.template.json
@@ -44,7 +44,9 @@
    "TLS_ENABLED": true
  },
  "ESPLORA": {
-    "REST_API_URL": "__ESPLORA_REST_API_URL__"
+    "REST_API_URL": "__ESPLORA_REST_API_URL__",
+    "UNIX_SOCKET_PATH": "__ESPLORA_UNIX_SOCKET_PATH__",
+    "RETRY_UNIX_SOCKET_AFTER": "__ESPLORA_RETRY_UNIX_SOCKET_AFTER__"
  },
  "SECOND_CORE_RPC": {
    "HOST": "__SECOND_CORE_RPC_HOST__",
@@ -60,7 +62,8 @@
    "PORT": 18,
    "DATABASE": "__DATABASE_DATABASE__",
    "USERNAME": "__DATABASE_USERNAME__",
-    "PASSWORD": "__DATABASE_PASSWORD__"
+    "PASSWORD": "__DATABASE_PASSWORD__",
+    "TIMEOUT": "__DATABASE_TIMEOUT__"
  },
  "SYSLOG": {
    "ENABLED": false,
--- a/backend/src/tests/config.test.ts
+++ b/backend/src/tests/config.test.ts
@@ -47,7 +47,7 @@ describe('Mempool Backend Config', () => {

      expect(config.ELECTRUM).toStrictEqual({ HOST: '127.0.0.1', PORT: 3306, TLS_ENABLED: true });

-      expect(config.ESPLORA).toStrictEqual({ REST_API_URL: 'http://127.0.0.1:3000' });
+      expect(config.ESPLORA).toStrictEqual({ REST_API_URL: 'http://127.0.0.1:3000', UNIX_SOCKET_PATH: null, RETRY_UNIX_SOCKET_AFTER: 30000 });

      expect(config.CORE_RPC).toStrictEqual({
        HOST: '127.0.0.1',
@@ -72,7 +72,8 @@ describe('Mempool Backend Config', () => {
        PORT: 3306,
        DATABASE: 'mempool',
        USERNAME: 'mempool',
-        PASSWORD: 'mempool'
+        PASSWORD: 'mempool',
+        TIMEOUT: 180000,
      });

      expect(config.SYSLOG).toStrictEqual({
--- a/backend/src/api/audit.ts
+++ b/backend/src/api/audit.ts
@@ -93,17 +93,7 @@ class Audit {
      } else {
        if (!isDisplaced[tx.txid]) {
          added.push(tx.txid);
-        } else {
        }
-        let blockIndex = -1;
-        let index = -1;
-        projectedBlocks.forEach((block, bi) => {
-          const i = block.transactionIds.indexOf(tx.txid);
-          if (i >= 0) {
-            blockIndex = bi;
-            index = i;
-          }
-        });
        overflowWeight += tx.weight;
      }
      totalWeight += tx.weight;
--- a/backend/src/api/bitcoin/bitcoin.routes.ts
+++ b/backend/src/api/bitcoin/bitcoin.routes.ts
@@ -32,8 +32,10 @@ class BitcoinRoutes {
      .get(config.MEMPOOL.API_URL_PREFIX + 'backend-info', this.getBackendInfo)
      .get(config.MEMPOOL.API_URL_PREFIX + 'init-data', this.getInitData)
      .get(config.MEMPOOL.API_URL_PREFIX + 'validate-address/:address', this.validateAddress)
-      .get(config.MEMPOOL.API_URL_PREFIX + 'tx/:txId/replaces', this.getRbfHistory)
+      .get(config.MEMPOOL.API_URL_PREFIX + 'tx/:txId/rbf', this.getRbfHistory)
      .get(config.MEMPOOL.API_URL_PREFIX + 'tx/:txId/cached', this.getCachedTx)
+      .get(config.MEMPOOL.API_URL_PREFIX + 'replacements', this.getRbfReplacements)
+      .get(config.MEMPOOL.API_URL_PREFIX + 'fullrbf/replacements', this.getFullRbfReplacements)
      .post(config.MEMPOOL.API_URL_PREFIX + 'tx/push', this.$postTransactionForm)
      .get(config.MEMPOOL.API_URL_PREFIX + 'donations', async (req, res) => {
        try {
@@ -94,6 +96,7 @@ class BitcoinRoutes {
      .get(config.MEMPOOL.API_URL_PREFIX + 'block/:hash', this.getBlock)
      .get(config.MEMPOOL.API_URL_PREFIX + 'block/:hash/summary', this.getStrippedBlockTransactions)
      .get(config.MEMPOOL.API_URL_PREFIX + 'block/:hash/audit-summary', this.getBlockAuditSummary)
+      .get(config.MEMPOOL.API_URL_PREFIX + 'blocks/tip/height', this.getBlockTipHeight)
      .post(config.MEMPOOL.API_URL_PREFIX + 'psbt/addparents', this.postPsbtCompletion)
      .get(config.MEMPOOL.API_URL_PREFIX + 'blocks-bulk/:from', this.getBlocksByBulk.bind(this))
      .get(config.MEMPOOL.API_URL_PREFIX + 'blocks-bulk/:from/:to', this.getBlocksByBulk.bind(this))
@@ -110,7 +113,6 @@ class BitcoinRoutes {
          .get(config.MEMPOOL.API_URL_PREFIX + 'tx/:txId/status', this.getTransactionStatus)
          .get(config.MEMPOOL.API_URL_PREFIX + 'tx/:txId/outspends', this.getTransactionOutspends)
          .get(config.MEMPOOL.API_URL_PREFIX + 'block/:hash/header', this.getBlockHeader)
-          .get(config.MEMPOOL.API_URL_PREFIX + 'blocks/tip/height', this.getBlockTipHeight)
          .get(config.MEMPOOL.API_URL_PREFIX + 'blocks/tip/hash', this.getBlockTipHash)
          .get(config.MEMPOOL.API_URL_PREFIX + 'block/:hash/raw', this.getRawBlock)
          .get(config.MEMPOOL.API_URL_PREFIX + 'block/:hash/txids', this.getTxIdsForBlock)
@@ -128,8 +130,9 @@ class BitcoinRoutes {

  private getInitData(req: Request, res: Response) {
    try {
-      const result = websocketHandler.getInitData();
-      res.json(result);
+      const result = websocketHandler.getSerializedInitData();
+      res.set('Content-Type', 'application/json');
+      res.send(result);
    } catch (e) {
      res.status(500).send(e instanceof Error ? e.message : e);
    }
@@ -589,10 +592,14 @@ class BitcoinRoutes {
    }
  }

-  private async getBlockTipHeight(req: Request, res: Response) {
+  private getBlockTipHeight(req: Request, res: Response) {
    try {
-      const result = await bitcoinApi.$getBlockHeightTip();
-      res.json(result);
+      const result = blocks.getCurrentBlockHeight();
+      if (!result) {
+        return res.status(503).send(`Service Temporarily Unavailable`);
+      }
+      res.setHeader('content-type', 'text/plain');
+      res.send(result.toString());
    } catch (e) {
      res.status(500).send(e instanceof Error ? e.message : e);
    }
@@ -638,8 +645,30 @@ class BitcoinRoutes {

  private async getRbfHistory(req: Request, res: Response) {
    try {
-      const result = rbfCache.getReplaces(req.params.txId);
-      res.json(result || []);
+      const replacements = rbfCache.getRbfTree(req.params.txId) || null;
+      const replaces = rbfCache.getReplaces(req.params.txId) || null;
+      res.json({
+        replacements,
+        replaces
+      });
+    } catch (e) {
+      res.status(500).send(e instanceof Error ? e.message : e);
+    }
+  }
+
+  private async getRbfReplacements(req: Request, res: Response) {
+    try {
+      const result = rbfCache.getRbfTrees(false);
+      res.json(result);
+    } catch (e) {
+      res.status(500).send(e instanceof Error ? e.message : e);
+    }
+  }
+
+  private async getFullRbfReplacements(req: Request, res: Response) {
+    try {
+      const result = rbfCache.getRbfTrees(true);
+      res.json(result);
    } catch (e) {
      res.status(500).send(e instanceof Error ? e.message : e);
    }
--- a/backend/src/api/bitcoin/esplora-api.ts
+++ b/backend/src/api/bitcoin/esplora-api.ts
@@ -3,65 +3,102 @@ import axios, { AxiosRequestConfig } from 'axios';
 import http from 'http';
 import { AbstractBitcoinApi } from './bitcoin-api-abstract-factory';
 import { IEsploraApi } from './esplora-api.interface';
+import logger from '../../logger';

 const axiosConnection = axios.create({
-  httpAgent: new http.Agent({ keepAlive: true })
+  httpAgent: new http.Agent({ keepAlive: true, })
 });

 class ElectrsApi implements AbstractBitcoinApi {
-  axiosConfig: AxiosRequestConfig = {
+  private axiosConfigWithUnixSocket: AxiosRequestConfig = config.ESPLORA.UNIX_SOCKET_PATH ? {
+    socketPath: config.ESPLORA.UNIX_SOCKET_PATH,
+    timeout: 10000,
+  } : {
+    timeout: 10000,
+  };
+  private axiosConfigTcpSocketOnly: AxiosRequestConfig = {
    timeout: 10000,
  };

-  constructor() { }
+  unixSocketRetryTimeout;
+  activeAxiosConfig;
+
+  constructor() {
+    this.activeAxiosConfig = this.axiosConfigWithUnixSocket;
+  }
+
+  fallbackToTcpSocket() {
+    if (!this.unixSocketRetryTimeout) {
+      logger.err(`Unable to connect to esplora unix socket. Falling back to tcp socket. Retrying unix socket in ${config.ESPLORA.RETRY_UNIX_SOCKET_AFTER / 1000} seconds`);
+      // Retry the unix socket after a few seconds
+      this.unixSocketRetryTimeout = setTimeout(() => {
+        logger.info(`Retrying to use unix socket for esplora now (applied for the next query)`);
+        this.activeAxiosConfig = this.axiosConfigWithUnixSocket;
+        this.unixSocketRetryTimeout = undefined;
+      }, config.ESPLORA.RETRY_UNIX_SOCKET_AFTER);
+    }
+
+    // Use the TCP socket (reach a different esplora instance through nginx)
+    this.activeAxiosConfig = this.axiosConfigTcpSocketOnly;
+  }
+
+  $queryWrapper<T>(url, responseType = 'json'): Promise<T> {
+    return axiosConnection.get<T>(url, { ...this.activeAxiosConfig, responseType: responseType })
+      .then((response) => response.data)
+      .catch((e) => {
+        if (e?.code === 'ECONNREFUSED') {
+          this.fallbackToTcpSocket();
+          // Retry immediately
+          return axiosConnection.get<T>(url, this.activeAxiosConfig)
+            .then((response) => response.data)
+            .catch((e) => {
+              logger.warn(`Cannot query esplora through the unix socket nor the tcp socket. Exception ${e}`);
+              throw e;
+            });
+        } else {
+          throw e;
+        }
+      });
+  }

  $getRawMempool(): Promise<IEsploraApi.Transaction['txid'][]> {
-    return axiosConnection.get<IEsploraApi.Transaction['txid'][]>(config.ESPLORA.REST_API_URL + '/mempool/txids', this.axiosConfig)
-      .then((response) => response.data);
+    return this.$queryWrapper<IEsploraApi.Transaction['txid'][]>(config.ESPLORA.REST_API_URL + '/mempool/txids');
  }

  $getRawTransaction(txId: string): Promise<IEsploraApi.Transaction> {
-    return axiosConnection.get<IEsploraApi.Transaction>(config.ESPLORA.REST_API_URL + '/tx/' + txId, this.axiosConfig)
-      .then((response) => response.data);
+    return this.$queryWrapper<IEsploraApi.Transaction>(config.ESPLORA.REST_API_URL + '/tx/' + txId);
  }

  $getTransactionHex(txId: string): Promise<string> {
-    return axiosConnection.get<string>(config.ESPLORA.REST_API_URL + '/tx/' + txId + '/hex', this.axiosConfig)
-      .then((response) => response.data);
+    return this.$queryWrapper<string>(config.ESPLORA.REST_API_URL + '/tx/' + txId + '/hex');
  }

  $getBlockHeightTip(): Promise<number> {
-    return axiosConnection.get<number>(config.ESPLORA.REST_API_URL + '/blocks/tip/height', this.axiosConfig)
-      .then((response) => response.data);
+    return this.$queryWrapper<number>(config.ESPLORA.REST_API_URL + '/blocks/tip/height');
  }

  $getBlockHashTip(): Promise<string> {
-    return axiosConnection.get<string>(config.ESPLORA.REST_API_URL + '/blocks/tip/hash', this.axiosConfig)
-      .then((response) => response.data);
+    return this.$queryWrapper<string>(config.ESPLORA.REST_API_URL + '/blocks/tip/hash');
  }

  $getTxIdsForBlock(hash: string): Promise<string[]> {
-    return axiosConnection.get<string[]>(config.ESPLORA.REST_API_URL + '/block/' + hash + '/txids', this.axiosConfig)
-      .then((response) => response.data);
+    return this.$queryWrapper<string[]>(config.ESPLORA.REST_API_URL + '/block/' + hash + '/txids');
  }

  $getBlockHash(height: number): Promise<string> {
-    return axiosConnection.get<string>(config.ESPLORA.REST_API_URL + '/block-height/' + height, this.axiosConfig)
-      .then((response) => response.data);
+    return this.$queryWrapper<string>(config.ESPLORA.REST_API_URL + '/block-height/' + height);
  }

  $getBlockHeader(hash: string): Promise<string> {
-    return axiosConnection.get<string>(config.ESPLORA.REST_API_URL + '/block/' + hash + '/header', this.axiosConfig)
-      .then((response) => response.data);
+    return this.$queryWrapper<string>(config.ESPLORA.REST_API_URL + '/block/' + hash + '/header');
  }

  $getBlock(hash: string): Promise<IEsploraApi.Block> {
-    return axiosConnection.get<IEsploraApi.Block>(config.ESPLORA.REST_API_URL + '/block/' + hash, this.axiosConfig)
-      .then((response) => response.data);
+    return this.$queryWrapper<IEsploraApi.Block>(config.ESPLORA.REST_API_URL + '/block/' + hash);
  }

  $getRawBlock(hash: string): Promise<Buffer> {
-    return axiosConnection.get<string>(config.ESPLORA.REST_API_URL + '/block/' + hash + "/raw", { ...this.axiosConfig, responseType: 'arraybuffer' })
+    return this.$queryWrapper<any>(config.ESPLORA.REST_API_URL + '/block/' + hash + "/raw", 'arraybuffer')
      .then((response) => { return Buffer.from(response.data); });
  }

@@ -82,13 +119,11 @@ class ElectrsApi implements AbstractBitcoinApi {
  }

  $getOutspend(txId: string, vout: number): Promise<IEsploraApi.Outspend> {
-    return axiosConnection.get<IEsploraApi.Outspend>(config.ESPLORA.REST_API_URL + '/tx/' + txId + '/outspend/' + vout, this.axiosConfig)
-      .then((response) => response.data);
+    return this.$queryWrapper<IEsploraApi.Outspend>(config.ESPLORA.REST_API_URL + '/tx/' + txId + '/outspend/' + vout);
  }

  $getOutspends(txId: string): Promise<IEsploraApi.Outspend[]> {
-    return axiosConnection.get<IEsploraApi.Outspend[]>(config.ESPLORA.REST_API_URL + '/tx/' + txId + '/outspends', this.axiosConfig)
-      .then((response) => response.data);
+    return this.$queryWrapper<IEsploraApi.Outspend[]>(config.ESPLORA.REST_API_URL + '/tx/' + txId + '/outspends');
  }

  async $getBatchedOutspends(txId: string[]): Promise<IEsploraApi.Outspend[][]> {
--- a/backend/src/api/blocks.ts
+++ b/backend/src/api/blocks.ts
@@ -36,6 +36,8 @@ class Blocks {
  private newBlockCallbacks: ((block: BlockExtended, txIds: string[], transactions: TransactionExtended[]) => void)[] = [];
  private newAsyncBlockCallbacks: ((block: BlockExtended, txIds: string[], transactions: TransactionExtended[]) => Promise<void>)[] = [];

+  private mainLoopTimeout: number = 120000;
+
  constructor() { }

  public getBlocks(): BlockExtended[] {
@@ -410,12 +412,13 @@ class Blocks {
    try {
      // Get all indexed block hash
      const unindexedBlockHeights = await blocksRepository.$getCPFPUnindexedBlocks();
-      logger.info(`Indexing cpfp data for ${unindexedBlockHeights.length} blocks`);

      if (!unindexedBlockHeights?.length) {
        return;
      }

+      logger.info(`Indexing cpfp data for ${unindexedBlockHeights.length} blocks`);
+
      // Logging
      let count = 0;
      let countThisRun = 0;
@@ -526,9 +529,16 @@ class Blocks {
    return await BlocksRepository.$validateChain();
  }

-  public async $updateBlocks() {
+  public async $updateBlocks(): Promise<number> {
+    // warn if this run stalls the main loop for more than 2 minutes
+    const timer = this.startTimer();
+
+    diskCache.lock();
+
    let fastForwarded = false;
+    let handledBlocks = 0;
    const blockHeightTip = await bitcoinApi.$getBlockHeightTip();
+    this.updateTimerProgress(timer, 'got block height tip');

    if (this.blocks.length === 0) {
      this.currentBlockHeight = Math.max(blockHeightTip - config.MEMPOOL.INITIAL_BLOCKS_AMOUNT, -1);
@@ -546,16 +556,21 @@ class Blocks {

    if (!this.lastDifficultyAdjustmentTime) {
      const blockchainInfo = await bitcoinClient.getBlockchainInfo();
+      this.updateTimerProgress(timer, 'got blockchain info for initial difficulty adjustment');
      if (blockchainInfo.blocks === blockchainInfo.headers) {
        const heightDiff = blockHeightTip % 2016;
        const blockHash = await bitcoinApi.$getBlockHash(blockHeightTip - heightDiff);
+        this.updateTimerProgress(timer, 'got block hash for initial difficulty adjustment');
        const block: IEsploraApi.Block = await bitcoinCoreApi.$getBlock(blockHash);
+        this.updateTimerProgress(timer, 'got block for initial difficulty adjustment');
        this.lastDifficultyAdjustmentTime = block.timestamp;
        this.currentDifficulty = block.difficulty;

        if (blockHeightTip >= 2016) {
          const previousPeriodBlockHash = await bitcoinApi.$getBlockHash(blockHeightTip - heightDiff - 2016);
+          this.updateTimerProgress(timer, 'got previous block hash for initial difficulty adjustment');
          const previousPeriodBlock: IEsploraApi.Block = await bitcoinCoreApi.$getBlock(previousPeriodBlockHash);
+          this.updateTimerProgress(timer, 'got previous block for initial difficulty adjustment');
          this.previousDifficultyRetarget = (block.difficulty - previousPeriodBlock.difficulty) / previousPeriodBlock.difficulty * 100;
          logger.debug(`Initial difficulty adjustment data set.`);
        }
@@ -570,9 +585,11 @@ class Blocks {
      } else {
        this.currentBlockHeight++;
        logger.debug(`New block found (#${this.currentBlockHeight})!`);
+        this.updateTimerProgress(timer, `getting orphaned blocks for ${this.currentBlockHeight}`);
        await chainTips.updateOrphanedBlocks();
      }

+      this.updateTimerProgress(timer, `getting block data for ${this.currentBlockHeight}`);
      const blockHash = await bitcoinApi.$getBlockHash(this.currentBlockHeight);
      const verboseBlock = await bitcoinClient.getBlock(blockHash, 2);
      const block = BitcoinApi.convertBlock(verboseBlock);
@@ -581,42 +598,53 @@ class Blocks {
      const cpfpSummary: CpfpSummary = Common.calculateCpfp(block.height, transactions);
      const blockExtended: BlockExtended = await this.$getBlockExtended(block, cpfpSummary.transactions);
      const blockSummary: BlockSummary = this.summarizeBlock(verboseBlock);
+      this.updateTimerProgress(timer, `got block data for ${this.currentBlockHeight}`);

      // start async callbacks
+      this.updateTimerProgress(timer, `starting async callbacks for ${this.currentBlockHeight}`);
      const callbackPromises = this.newAsyncBlockCallbacks.map((cb) => cb(blockExtended, txIds, transactions));

      if (Common.indexingEnabled()) {
        if (!fastForwarded) {
          const lastBlock = await blocksRepository.$getBlockByHeight(blockExtended.height - 1);
+          this.updateTimerProgress(timer, `got block by height for ${this.currentBlockHeight}`);
          if (lastBlock !== null && blockExtended.previousblockhash !== lastBlock.id) {
-            logger.warn(`Chain divergence detected at block ${lastBlock.height}, re-indexing most recent data`);
+            logger.warn(`Chain divergence detected at block ${lastBlock.height}, re-indexing most recent data`, logger.tags.mining);
            // We assume there won't be a reorg with more than 10 block depth
+            this.updateTimerProgress(timer, `rolling back diverged chain from ${this.currentBlockHeight}`);
            await BlocksRepository.$deleteBlocksFrom(lastBlock.height - 10);
            await HashratesRepository.$deleteLastEntries();
-            await BlocksSummariesRepository.$deleteBlocksFrom(lastBlock.height - 10);
            await cpfpRepository.$deleteClustersFrom(lastBlock.height - 10);
+            this.updateTimerProgress(timer, `rolled back chain divergence from ${this.currentBlockHeight}`);
            for (let i = 10; i >= 0; --i) {
              const newBlock = await this.$indexBlock(lastBlock.height - i);
+              this.updateTimerProgress(timer, `reindexed block`);
              await this.$getStrippedBlockTransactions(newBlock.id, true, true);
+              this.updateTimerProgress(timer, `reindexed block summary`);
              if (config.MEMPOOL.CPFP_INDEXING) {
                await this.$indexCPFP(newBlock.id, lastBlock.height - i);
+                this.updateTimerProgress(timer, `reindexed block cpfp`);
              }
            }
            await mining.$indexDifficultyAdjustments();
            await DifficultyAdjustmentsRepository.$deleteLastAdjustment();
-            logger.info(`Re-indexed 10 blocks and summaries. Also re-indexed the last difficulty adjustments. Will re-index latest hashrates in a few seconds.`);
+            this.updateTimerProgress(timer, `reindexed difficulty adjustments`);
+            logger.info(`Re-indexed 10 blocks and summaries. Also re-indexed the last difficulty adjustments. Will re-index latest hashrates in a few seconds.`, logger.tags.mining);
            indexer.reindex();
          }
          await blocksRepository.$saveBlockInDatabase(blockExtended);
+          this.updateTimerProgress(timer, `saved ${this.currentBlockHeight} to database`);

          const lastestPriceId = await PricesRepository.$getLatestPriceId();
+          this.updateTimerProgress(timer, `got latest price id ${this.currentBlockHeight}`);
          if (priceUpdater.historyInserted === true && lastestPriceId !== null) {
            await blocksRepository.$saveBlockPrices([{
              height: blockExtended.height,
              priceId: lastestPriceId,
            }]);
+            this.updateTimerProgress(timer, `saved prices for ${this.currentBlockHeight}`);
          } else {
-            logger.info(`Cannot save block price for ${blockExtended.height} because the price updater hasnt completed yet. Trying again in 10 seconds.`, logger.tags.mining);
+            logger.debug(`Cannot save block price for ${blockExtended.height} because the price updater hasnt completed yet. Trying again in 10 seconds.`, logger.tags.mining);
            setTimeout(() => {
              indexer.runSingleTask('blocksPrices');
            }, 10000);
@@ -625,9 +653,11 @@ class Blocks {
          // Save blocks summary for visualization if it's enabled
          if (Common.blocksSummariesIndexingEnabled() === true) {
            await this.$getStrippedBlockTransactions(blockExtended.id, true);
+            this.updateTimerProgress(timer, `saved block summary for ${this.currentBlockHeight}`);
          }
          if (config.MEMPOOL.CPFP_INDEXING) {
            this.$saveCpfp(blockExtended.id, this.currentBlockHeight, cpfpSummary);
+            this.updateTimerProgress(timer, `saved cpfp for ${this.currentBlockHeight}`);
          }
        }
      }
@@ -640,6 +670,7 @@ class Blocks {
            difficulty: block.difficulty,
            adjustment: Math.round((block.difficulty / this.currentDifficulty) * 1000000) / 1000000, // Remove float point noise
          });
+          this.updateTimerProgress(timer, `saved difficulty adjustment for ${this.currentBlockHeight}`);
        }

        this.previousDifficultyRetarget = (block.difficulty - this.currentDifficulty) / this.currentDifficulty * 100;
@@ -664,7 +695,39 @@ class Blocks {
      }

      // wait for pending async callbacks to finish
+      this.updateTimerProgress(timer, `waiting for async callbacks to complete for ${this.currentBlockHeight}`);
      await Promise.all(callbackPromises);
+      this.updateTimerProgress(timer, `async callbacks completed for ${this.currentBlockHeight}`);
+
+      handledBlocks++;
+    }
+
+    diskCache.unlock();
+
+    this.clearTimer(timer);
+
+    return handledBlocks;
+  }
+
+  private startTimer() {
+    const state: any = {
+      start: Date.now(),
+      progress: 'begin $updateBlocks',
+      timer: null,
+    };
+    state.timer = setTimeout(() => {
+      logger.err(`$updateBlocks stalled at "${state.progress}"`);
+    }, this.mainLoopTimeout);
+    return state;
+  }
+
+  private updateTimerProgress(state, msg) {
+    state.progress = msg;
+  }
+
+  private clearTimer(state) {
+    if (state.timer) {
+      clearTimeout(state.timer);
    }
  }

@@ -736,7 +799,7 @@ class Blocks {

    // Index the response if needed
    if (Common.blocksSummariesIndexingEnabled() === true) {
-      await BlocksSummariesRepository.$saveSummary({height: block.height, mined: summary});
+      await BlocksSummariesRepository.$saveTransactions(block.height, block.hash, summary.transactions);
    }

    return summary.transactions;
@@ -852,11 +915,12 @@ class Blocks {
        if (cleanBlock.fee_amt_percentiles === null) {
          const block = await bitcoinClient.getBlock(cleanBlock.hash, 2);
          const summary = this.summarizeBlock(block);
-          await BlocksSummariesRepository.$saveSummary({ height: block.height, mined: summary });
+          await BlocksSummariesRepository.$saveTransactions(cleanBlock.height, cleanBlock.hash, summary.transactions);
          cleanBlock.fee_amt_percentiles = await BlocksSummariesRepository.$getFeePercentilesByBlockId(cleanBlock.hash);
        }
        if (cleanBlock.fee_amt_percentiles !== null) {
          cleanBlock.median_fee_amt = cleanBlock.fee_amt_percentiles[3];
+          await blocksRepository.$updateFeeAmounts(cleanBlock.hash, cleanBlock.fee_amt_percentiles, cleanBlock.median_fee_amt);
        }
      }

--- a/backend/src/api/common.ts
+++ b/backend/src/api/common.ts
@@ -57,11 +57,11 @@ export class Common {
    return arr;
  }

-  static findRbfTransactions(added: TransactionExtended[], deleted: TransactionExtended[]): { [txid: string]: TransactionExtended } {
-    const matches: { [txid: string]: TransactionExtended } = {};
-    deleted
-      .forEach((deletedTx) => {
-        const foundMatches = added.find((addedTx) => {
+  static findRbfTransactions(added: TransactionExtended[], deleted: TransactionExtended[]): { [txid: string]: TransactionExtended[] } {
+    const matches: { [txid: string]: TransactionExtended[] } = {};
+    added
+      .forEach((addedTx) => {
+        const foundMatches = deleted.filter((deletedTx) => {
          // The new tx must, absolutely speaking, pay at least as much fee as the replaced tx.
          return addedTx.fee > deletedTx.fee
            // The new transaction must pay more fee per kB than the replaced tx.
@@ -70,8 +70,8 @@ export class Common {
            && deletedTx.vin.some((deletedVin) =>
              addedTx.vin.some((vin) => vin.txid === deletedVin.txid && vin.vout === deletedVin.vout));
            });
-        if (foundMatches) {
-          matches[deletedTx.txid] = foundMatches;
+        if (foundMatches?.length) {
+          matches[addedTx.txid] = foundMatches;
        }
      });
    return matches;
@@ -83,6 +83,7 @@ export class Common {
      fee: tx.fee,
      vsize: tx.weight / 4,
      value: tx.vout.reduce((acc, vout) => acc + (vout.value ? vout.value : 0), 0),
+      rate: tx.effectiveFeePerVsize,
    };
  }

--- a/backend/src/api/disk-cache.ts
+++ b/backend/src/api/disk-cache.ts
@@ -7,17 +7,26 @@ import logger from '../logger';
 import config from '../config';
 import { TransactionExtended } from '../mempool.interfaces';
 import { Common } from './common';
+import rbfCache from './rbf-cache';

 class DiskCache {
  private cacheSchemaVersion = 3;
+  private rbfCacheSchemaVersion = 1;

  private static TMP_FILE_NAME = config.MEMPOOL.CACHE_DIR + '/tmp-cache.json';
  private static TMP_FILE_NAMES = config.MEMPOOL.CACHE_DIR + '/tmp-cache{number}.json';
  private static FILE_NAME = config.MEMPOOL.CACHE_DIR + '/cache.json';
  private static FILE_NAMES = config.MEMPOOL.CACHE_DIR + '/cache{number}.json';
+  private static TMP_RBF_FILE_NAME = config.MEMPOOL.CACHE_DIR + '/tmp-rbfcache.json';
+  private static RBF_FILE_NAME = config.MEMPOOL.CACHE_DIR + '/rbfcache.json';
  private static CHUNK_FILES = 25;
  private isWritingCache = false;

+  private semaphore: { resume: (() => void)[], locks: number } = {
+    resume: [],
+    locks: 0,
+  };
+
  constructor() {
    if (!cluster.isPrimary) {
      return;
@@ -43,7 +52,7 @@ class DiskCache {
      const mempool = memPool.getMempool();
      const mempoolArray: TransactionExtended[] = [];
      for (const tx in mempool) {
-        if (mempool[tx] && !mempool[tx].deleteAfter) {
+        if (mempool[tx]) {
          mempoolArray.push(mempool[tx]);
        }
      }
@@ -73,6 +82,7 @@ class DiskCache {
          fs.renameSync(DiskCache.TMP_FILE_NAMES.replace('{number}', i.toString()), DiskCache.FILE_NAMES.replace('{number}', i.toString()));
        }
      } else {
+        await this.$yield();
        await fsPromises.writeFile(DiskCache.TMP_FILE_NAME, JSON.stringify({
          network: config.MEMPOOL.NETWORK,
          cacheSchemaVersion: this.cacheSchemaVersion,
@@ -82,6 +92,7 @@ class DiskCache {
          mempoolArray: mempoolArray.splice(0, chunkSize),
        }), { flag: 'w' });
        for (let i = 1; i < DiskCache.CHUNK_FILES; i++) {
+          await this.$yield();
          await fsPromises.writeFile(DiskCache.TMP_FILE_NAMES.replace('{number}', i.toString()), JSON.stringify({
            mempool: {},
            mempoolArray: mempoolArray.splice(0, chunkSize),
@@ -100,6 +111,32 @@ class DiskCache {
      logger.warn('Error writing to cache file: ' + (e instanceof Error ? e.message : e));
      this.isWritingCache = false;
    }
+
+    try {
+      logger.debug('Writing rbf data to disk cache (async)...');
+      this.isWritingCache = true;
+      const rbfData = rbfCache.dump();
+      if (sync) {
+        fs.writeFileSync(DiskCache.TMP_RBF_FILE_NAME, JSON.stringify({
+          network: config.MEMPOOL.NETWORK,
+          rbfCacheSchemaVersion: this.rbfCacheSchemaVersion,
+          rbf: rbfData,
+        }), { flag: 'w' });
+        fs.renameSync(DiskCache.TMP_RBF_FILE_NAME, DiskCache.RBF_FILE_NAME);
+      } else {
+        await fsPromises.writeFile(DiskCache.TMP_RBF_FILE_NAME, JSON.stringify({
+          network: config.MEMPOOL.NETWORK,
+          rbfCacheSchemaVersion: this.rbfCacheSchemaVersion,
+          rbf: rbfData,
+        }), { flag: 'w' });
+        await fsPromises.rename(DiskCache.TMP_RBF_FILE_NAME, DiskCache.RBF_FILE_NAME);
+      }
+      logger.debug('Rbf data saved to disk cache');
+      this.isWritingCache = false;
+    } catch (e) {
+      logger.warn('Error writing rbf data to cache file: ' + (e instanceof Error ? e.message : e));
+      this.isWritingCache = false;
+    }
  }

  wipeCache(): void {
@@ -124,7 +161,19 @@ class DiskCache {
    }
  }

-  loadMempoolCache(): void {
+  wipeRbfCache() {
+    logger.notice(`Wipping nodejs backend cache/rbfcache.json file`);
+
+    try {
+      fs.unlinkSync(DiskCache.RBF_FILE_NAME);
+    } catch (e: any) {
+      if (e?.code !== 'ENOENT') {
+        logger.err(`Cannot wipe cache file ${DiskCache.RBF_FILE_NAME}. Exception ${JSON.stringify(e)}`);
+      }
+    }
+  }
+
+  async $loadMempoolCache(): Promise<void> {
    if (!fs.existsSync(DiskCache.FILE_NAME)) {
      return;
    }
@@ -164,16 +213,65 @@ class DiskCache {
            }
          }
        } catch (e) {
-          logger.info('Error parsing ' + fileName + '. Skipping. Reason: ' + (e instanceof Error ? e.message : e));
+          logger.err('Error parsing ' + fileName + '. Skipping. Reason: ' + (e instanceof Error ? e.message : e));
        }
      }

-      memPool.setMempool(data.mempool);
+      await memPool.$setMempool(data.mempool);
      blocks.setBlocks(data.blocks);
      blocks.setBlockSummaries(data.blockSummaries || []);
    } catch (e) {
      logger.warn('Failed to parse mempoool and blocks cache. Skipping. Reason: ' + (e instanceof Error ? e.message : e));
    }
+
+    try {
+      let rbfData: any = {};
+      const rbfCacheData = fs.readFileSync(DiskCache.RBF_FILE_NAME, 'utf8');
+      if (rbfCacheData) {
+        logger.info('Restoring rbf data from disk cache');
+        rbfData = JSON.parse(rbfCacheData);
+        if (rbfData.rbfCacheSchemaVersion === undefined || rbfData.rbfCacheSchemaVersion !== this.rbfCacheSchemaVersion) {
+          logger.notice('Rbf disk cache contains an outdated schema version. Clearing it and skipping the cache loading.');
+          return this.wipeRbfCache();
+        }
+        if (rbfData.network && rbfData.network !== config.MEMPOOL.NETWORK) {
+          logger.notice('Rbf disk cache contains data from a different network. Clearing it and skipping the cache loading.');
+          return this.wipeRbfCache();
+        }
+      }
+
+      if (rbfData?.rbf) {
+        rbfCache.load(rbfData.rbf);
+      }
+    } catch (e) {
+      logger.warn('Failed to parse rbf cache. Skipping. Reason: ' + (e instanceof Error ? e.message : e));
+    }
+  }
+
+  private $yield(): Promise<void> {
+    if (this.semaphore.locks) {
+      logger.debug('Pause writing mempool and blocks data to disk cache (async)');
+      return new Promise((resolve) => {
+        this.semaphore.resume.push(resolve);
+      });
+    } else {
+      return Promise.resolve();
+    }
+  }
+
+  public lock(): void {
+    this.semaphore.locks++;
+  }
+
+  public unlock(): void {
+    this.semaphore.locks = Math.max(0, this.semaphore.locks - 1);
+    if (!this.semaphore.locks && this.semaphore.resume.length) {
+      const nextResume = this.semaphore.resume.shift();
+      if (nextResume) {
+        logger.debug('Resume writing mempool and blocks data to disk cache (async)');
+        nextResume();
+      }
+    }
  }
 }

--- a/backend/src/api/liquid/icons.ts
+++ b/backend/src/api/liquid/icons.ts
@@ -2,7 +2,7 @@ import * as fs from 'fs';
 import logger from '../../logger';

 class Icons {
-  private static FILE_NAME = './icons.json';
+  private static FILE_NAME = '/elements/asset_registry_db/icons.json';
  private iconIds: string[] = [];
  private icons: { [assetId: string]: string; } = {};

--- a/backend/src/api/mempool-blocks.ts
+++ b/backend/src/api/mempool-blocks.ts
@@ -1,5 +1,5 @@
 import logger from '../logger';
-import { MempoolBlock, TransactionExtended, ThreadTransaction, TransactionStripped, MempoolBlockWithTransactions, MempoolBlockDelta, Ancestor } from '../mempool.interfaces';
+import { MempoolBlock, TransactionExtended, TransactionStripped, MempoolBlockWithTransactions, MempoolBlockDelta, Ancestor, CompactThreadTransaction } from '../mempool.interfaces';
 import { Common } from './common';
 import config from '../config';
 import { Worker } from 'worker_threads';
@@ -10,6 +10,9 @@ class MempoolBlocks {
  private mempoolBlockDeltas: MempoolBlockDelta[] = [];
  private txSelectionWorker: Worker | null = null;

+  private nextUid: number = 1;
+  private uidMap: Map<number, string> = new Map(); // map short numerical uids to full txids
+
  constructor() {}

  public getMempoolBlocks(): MempoolBlock[] {
@@ -54,7 +57,14 @@ class MempoolBlocks {
    });

    // First sort
-    memPoolArray.sort((a, b) => b.feePerVsize - a.feePerVsize);
+    memPoolArray.sort((a, b) => {
+      if (a.feePerVsize === b.feePerVsize) {
+        // tie-break by lexicographic txid order for stability
+        return a.txid < b.txid ? -1 : 1;
+      } else {
+        return b.feePerVsize - a.feePerVsize;
+      }
+    });

    // Loop through and traverse all ancestors and sum up all the sizes + fees
    // Pass down size + fee to all unconfirmed children
@@ -68,7 +78,14 @@ class MempoolBlocks {
    });

    // Final sort, by effective fee
-    memPoolArray.sort((a, b) => b.effectiveFeePerVsize - a.effectiveFeePerVsize);
+    memPoolArray.sort((a, b) => {
+      if (a.effectiveFeePerVsize === b.effectiveFeePerVsize) {
+        // tie-break by lexicographic txid order for stability
+        return a.txid < b.txid ? -1 : 1;
+      } else {
+        return b.effectiveFeePerVsize - a.effectiveFeePerVsize;
+      }
+    });

    const end = new Date().getTime();
    const time = end - start;
@@ -87,21 +104,45 @@ class MempoolBlocks {

  private calculateMempoolBlocks(transactionsSorted: TransactionExtended[]): MempoolBlockWithTransactions[] {
    const mempoolBlocks: MempoolBlockWithTransactions[] = [];
+    let blockSize = 0;
    let blockWeight = 0;
+    let blockVsize = 0;
+    let blockFees = 0;
+    const sizeLimit = (config.MEMPOOL.BLOCK_WEIGHT_UNITS / 4) * 1.2;
+    let transactionIds: string[] = [];
    let transactions: TransactionExtended[] = [];
    transactionsSorted.forEach((tx) => {
      if (blockWeight + tx.weight <= config.MEMPOOL.BLOCK_WEIGHT_UNITS
        || mempoolBlocks.length === config.MEMPOOL.MEMPOOL_BLOCKS_AMOUNT - 1) {
+        tx.position = {
+          block: mempoolBlocks.length,
+          vsize: blockVsize + (tx.vsize / 2),
+        };
        blockWeight += tx.weight;
-        transactions.push(tx);
+        blockVsize += tx.vsize;
+        blockSize += tx.size;
+        blockFees += tx.fee;
+        if (blockVsize <= sizeLimit) {
+          transactions.push(tx);
+        }
+        transactionIds.push(tx.txid);
      } else {
-        mempoolBlocks.push(this.dataToMempoolBlocks(transactions));
+        mempoolBlocks.push(this.dataToMempoolBlocks(transactionIds, transactions, blockSize, blockWeight, blockFees));
+        blockVsize = 0;
+        tx.position = {
+          block: mempoolBlocks.length,
+          vsize: blockVsize + (tx.vsize / 2),
+        };
+        blockVsize += tx.vsize;
        blockWeight = tx.weight;
+        blockSize = tx.size;
+        blockFees = tx.fee;
+        transactionIds = [tx.txid];
        transactions = [tx];
      }
    });
    if (transactions.length) {
-      mempoolBlocks.push(this.dataToMempoolBlocks(transactions));
+      mempoolBlocks.push(this.dataToMempoolBlocks(transactionIds, transactions, blockSize, blockWeight, blockFees));
    }

    return mempoolBlocks;
@@ -112,6 +153,7 @@ class MempoolBlocks {
    for (let i = 0; i < Math.max(mempoolBlocks.length, prevBlocks.length); i++) {
      let added: TransactionStripped[] = [];
      let removed: string[] = [];
+      const changed: { txid: string, rate: number | undefined }[] = [];
      if (mempoolBlocks[i] && !prevBlocks[i]) {
        added = mempoolBlocks[i].transactions;
      } else if (!mempoolBlocks[i] && prevBlocks[i]) {
@@ -120,7 +162,7 @@ class MempoolBlocks {
        const prevIds = {};
        const newIds = {};
        prevBlocks[i].transactions.forEach(tx => {
-          prevIds[tx.txid] = true;
+          prevIds[tx.txid] = tx;
        });
        mempoolBlocks[i].transactions.forEach(tx => {
          newIds[tx.txid] = true;
@@ -133,30 +175,43 @@ class MempoolBlocks {
        mempoolBlocks[i].transactions.forEach(tx => {
          if (!prevIds[tx.txid]) {
            added.push(tx);
+          } else if (tx.rate !== prevIds[tx.txid].rate) {
+            changed.push({ txid: tx.txid, rate: tx.rate });
          }
        });
      }
      mempoolBlockDeltas.push({
        added,
-        removed
+        removed,
+        changed,
      });
    }
    return mempoolBlockDeltas;
  }

-  public async makeBlockTemplates(newMempool: { [txid: string]: TransactionExtended }, saveResults: boolean = false): Promise<MempoolBlockWithTransactions[]> {
+  public async $makeBlockTemplates(newMempool: { [txid: string]: TransactionExtended }, saveResults: boolean = false): Promise<MempoolBlockWithTransactions[]> {
+    const start = Date.now();
+
+    // reset mempool short ids
+    this.resetUids();
+    for (const tx of Object.values(newMempool)) {
+      this.setUid(tx);
+    }
+
    // prepare a stripped down version of the mempool with only the minimum necessary data
    // to reduce the overhead of passing this data to the worker thread
-    const strippedMempool: { [txid: string]: ThreadTransaction } = {};
-    Object.values(newMempool).filter(tx => !tx.deleteAfter).forEach(entry => {
-      strippedMempool[entry.txid] = {
-        txid: entry.txid,
-        fee: entry.fee,
-        weight: entry.weight,
-        feePerVsize: entry.fee / (entry.weight / 4),
-        effectiveFeePerVsize: entry.fee / (entry.weight / 4),
-        vin: entry.vin.map(v => v.txid),
-      };
+    const strippedMempool: Map<number, CompactThreadTransaction> = new Map();
+    Object.values(newMempool).forEach(entry => {
+      if (entry.uid != null) {
+        strippedMempool.set(entry.uid, {
+          uid: entry.uid,
+          fee: entry.fee,
+          weight: entry.weight,
+          feePerVsize: entry.fee / (entry.weight / 4),
+          effectiveFeePerVsize: entry.effectiveFeePerVsize || (entry.fee / (entry.weight / 4)),
+          inputs: entry.vin.map(v => this.getUid(newMempool[v.txid])).filter(uid => uid != null) as number[],
+        });
+      }
    });

    // (re)initialize tx selection worker thread
@@ -175,7 +230,7 @@ class MempoolBlocks {
    // run the block construction algorithm in a separate thread, and wait for a result
    let threadErrorListener;
    try {
-      const workerResultPromise = new Promise<{ blocks: ThreadTransaction[][], clusters: { [root: string]: string[] } }>((resolve, reject) => {
+      const workerResultPromise = new Promise<{ blocks: number[][], rates: Map<number, number>, clusters: Map<number, number[]> }>((resolve, reject) => {
        threadErrorListener = reject;
        this.txSelectionWorker?.once('message', (result): void => {
          resolve(result);
@@ -183,123 +238,151 @@ class MempoolBlocks {
        this.txSelectionWorker?.once('error', reject);
      });
      this.txSelectionWorker.postMessage({ type: 'set', mempool: strippedMempool });
-      let { blocks, clusters } = await workerResultPromise;
-      // filter out stale transactions
-      const unfilteredCount = blocks.reduce((total, block) => { return total + block.length; }, 0);
-      blocks = blocks.map(block => block.filter(tx => (tx.txid && tx.txid in newMempool)));
-      const filteredCount = blocks.reduce((total, block) => { return total + block.length; }, 0);
-      if (filteredCount < unfilteredCount) {
-        logger.warn(`tx selection worker thread returned ${unfilteredCount - filteredCount} stale transactions from makeBlockTemplates`);
-      }
+      const { blocks, rates, clusters } = this.convertResultTxids(await workerResultPromise);

      // clean up thread error listener
      this.txSelectionWorker?.removeListener('error', threadErrorListener);

-      return this.processBlockTemplates(newMempool, blocks, clusters, saveResults);
+      const processed = this.processBlockTemplates(newMempool, blocks, rates, clusters, saveResults);
+      logger.debug(`makeBlockTemplates completed in ${(Date.now() - start)/1000} seconds`);
+      return processed;
    } catch (e) {
      logger.err('makeBlockTemplates failed. ' + (e instanceof Error ? e.message : e));
    }
    return this.mempoolBlocks;
  }

-  public async updateBlockTemplates(newMempool: { [txid: string]: TransactionExtended }, added: TransactionExtended[], removed: string[], saveResults: boolean = false): Promise<void> {
+  public async $updateBlockTemplates(newMempool: { [txid: string]: TransactionExtended }, added: TransactionExtended[], removed: TransactionExtended[], saveResults: boolean = false): Promise<void> {
    if (!this.txSelectionWorker) {
      // need to reset the worker
-      this.makeBlockTemplates(newMempool, saveResults);
+      await this.$makeBlockTemplates(newMempool, saveResults);
      return;
    }
+
+    const start = Date.now();
+
+    for (const tx of Object.values(added)) {
+      this.setUid(tx);
+    }
+    const removedUids = removed.map(tx => this.getUid(tx)).filter(uid => uid != null) as number[];
    // prepare a stripped down version of the mempool with only the minimum necessary data
    // to reduce the overhead of passing this data to the worker thread
-    const addedStripped: ThreadTransaction[] = added.map(entry => {
+    const addedStripped: CompactThreadTransaction[] = added.filter(entry => entry.uid != null).map(entry => {
      return {
-        txid: entry.txid,
+        uid: entry.uid || 0,
        fee: entry.fee,
        weight: entry.weight,
        feePerVsize: entry.fee / (entry.weight / 4),
-        effectiveFeePerVsize: entry.fee / (entry.weight / 4),
-        vin: entry.vin.map(v => v.txid),
+        effectiveFeePerVsize: entry.effectiveFeePerVsize || (entry.fee / (entry.weight / 4)),
+        inputs: entry.vin.map(v => this.getUid(newMempool[v.txid])).filter(uid => uid != null) as number[],
      };
    });

    // run the block construction algorithm in a separate thread, and wait for a result
    let threadErrorListener;
    try {
-      const workerResultPromise = new Promise<{ blocks: ThreadTransaction[][], clusters: { [root: string]: string[] } }>((resolve, reject) => {
+      const workerResultPromise = new Promise<{ blocks: number[][], rates: Map<number, number>, clusters: Map<number, number[]> }>((resolve, reject) => {
        threadErrorListener = reject;
        this.txSelectionWorker?.once('message', (result): void => {
          resolve(result);
        });
        this.txSelectionWorker?.once('error', reject);
      });
-      this.txSelectionWorker.postMessage({ type: 'update', added: addedStripped, removed });
-      let { blocks, clusters } = await workerResultPromise;
-      // filter out stale transactions
-      const unfilteredCount = blocks.reduce((total, block) => { return total + block.length; }, 0);
-      blocks = blocks.map(block => block.filter(tx => (tx.txid && tx.txid in newMempool)));
-      const filteredCount = blocks.reduce((total, block) => { return total + block.length; }, 0);
-      if (filteredCount < unfilteredCount) {
-        logger.warn(`tx selection worker thread returned ${unfilteredCount - filteredCount} stale transactions from updateBlockTemplates`);
-      }
+      this.txSelectionWorker.postMessage({ type: 'update', added: addedStripped, removed: removedUids });
+      const { blocks, rates, clusters } = this.convertResultTxids(await workerResultPromise);
+
+      this.removeUids(removedUids);

      // clean up thread error listener
      this.txSelectionWorker?.removeListener('error', threadErrorListener);

-      this.processBlockTemplates(newMempool, blocks, clusters, saveResults);
+      this.processBlockTemplates(newMempool, blocks, rates, clusters, saveResults);
+      logger.debug(`updateBlockTemplates completed in ${(Date.now() - start) / 1000} seconds`);
    } catch (e) {
      logger.err('updateBlockTemplates failed. ' + (e instanceof Error ? e.message : e));
    }
  }

-  private processBlockTemplates(mempool, blocks, clusters, saveResults): MempoolBlockWithTransactions[] {
-    // update this thread's mempool with the results
-    blocks.forEach(block => {
-      block.forEach(tx => {
-        if (tx.txid && tx.txid in mempool) {
-          if (tx.effectiveFeePerVsize != null) {
-            mempool[tx.txid].effectiveFeePerVsize = tx.effectiveFeePerVsize;
-          }
-          if (tx.cpfpRoot && tx.cpfpRoot in clusters) {
-            const ancestors: Ancestor[] = [];
-            const descendants: Ancestor[] = [];
-            const cluster = clusters[tx.cpfpRoot];
-            let matched = false;
-            cluster.forEach(txid => {
-              if (!txid || !mempool[txid]) {
-                logger.warn('projected transaction ancestor missing from mempool cache');
-                return;
-              }
-              if (txid === tx.txid) {
-                matched = true;
-              } else {
-                const relative = {
-                  txid: txid,
-                  fee: mempool[txid].fee,
-                  weight: mempool[txid].weight,
-                };
-                if (matched) {
-                  descendants.push(relative);
-                } else {
-                  ancestors.push(relative);
-                }
-              }
-            });
-            mempool[tx.txid].ancestors = ancestors;
-            mempool[tx.txid].descendants = descendants;
-            mempool[tx.txid].bestDescendant = null;
-          }
-          mempool[tx.txid].cpfpChecked = tx.cpfpChecked;
-        } else {
-          logger.warn('projected transaction missing from mempool cache');
-        }
-      });
-    });
+  private processBlockTemplates(mempool, blocks: string[][], rates: { [root: string]: number }, clusters: { [root: string]: string[] }, saveResults): MempoolBlockWithTransactions[] {
+    for (const txid of Object.keys(rates)) {
+      if (txid in mempool) {
+        mempool[txid].effectiveFeePerVsize = rates[txid];
+      }
+    }

-    // unpack the condensed blocks into proper mempool blocks
-    const mempoolBlocks = blocks.map((transactions) => {
-      return this.dataToMempoolBlocks(transactions.map(tx => {
-        return mempool[tx.txid] || null;
-      }).filter(tx => !!tx));
-    });
+    const readyBlocks: { transactionIds, transactions, totalSize, totalWeight, totalFees }[] = [];
+    const sizeLimit = (config.MEMPOOL.BLOCK_WEIGHT_UNITS / 4) * 1.2;
+    // update this thread's mempool with the results
+    for (let blockIndex = 0; blockIndex < blocks.length; blockIndex++) {
+      const block: string[] = blocks[blockIndex];
+      let txid: string;
+      let mempoolTx: TransactionExtended;
+      let totalSize = 0;
+      let totalVsize = 0;
+      let totalWeight = 0;
+      let totalFees = 0;
+      const transactions: TransactionExtended[] = [];
+      for (let txIndex = 0; txIndex < block.length; txIndex++) {
+        txid = block[txIndex];
+        if (txid) {
+          mempoolTx = mempool[txid];
+          // save position in projected blocks
+          mempoolTx.position = {
+            block: blockIndex,
+            vsize: totalVsize + (mempoolTx.vsize / 2),
+          };
+          mempoolTx.cpfpChecked = true;
+
+          totalSize += mempoolTx.size;
+          totalVsize += mempoolTx.vsize;
+          totalWeight += mempoolTx.weight;
+          totalFees += mempoolTx.fee;
+
+          if (totalVsize <= sizeLimit) {
+            transactions.push(mempoolTx);
+          }
+        }
+      }
+      readyBlocks.push({
+        transactionIds: block,
+        transactions,
+        totalSize,
+        totalWeight,
+        totalFees
+      });
+    }
+
+    for (const cluster of Object.values(clusters)) {
+      for (const memberTxid of cluster) {
+        if (memberTxid in mempool) {
+          const mempoolTx = mempool[memberTxid];
+          const ancestors: Ancestor[] = [];
+          const descendants: Ancestor[] = [];
+          let matched = false;
+          cluster.forEach(txid => {
+            if (txid === memberTxid) {
+              matched = true;
+            } else {
+              const relative = {
+                txid: txid,
+                fee: mempool[txid].fee,
+                weight: mempool[txid].weight,
+              };
+              if (matched) {
+                descendants.push(relative);
+              } else {
+                ancestors.push(relative);
+              }
+            }
+          });
+          mempoolTx.ancestors = ancestors;
+          mempoolTx.descendants = descendants;
+          mempoolTx.bestDescendant = null;
+        }
+      }
+    }
+
+    const mempoolBlocks = readyBlocks.map(b => this.dataToMempoolBlocks(b.transactionIds, b.transactions, b.totalSize, b.totalWeight, b.totalFees));

    if (saveResults) {
      const deltas = this.calculateMempoolDeltas(this.mempoolBlocks, mempoolBlocks);
@@ -310,29 +393,69 @@ class MempoolBlocks {
    return mempoolBlocks;
  }

-  private dataToMempoolBlocks(transactions: TransactionExtended[]): MempoolBlockWithTransactions {
-    let totalSize = 0;
-    let totalWeight = 0;
-    const fitTransactions: TransactionExtended[] = [];
-    transactions.forEach(tx => {
-      totalSize += tx.size;
-      totalWeight += tx.weight;
-      if ((totalWeight + tx.weight) <= config.MEMPOOL.BLOCK_WEIGHT_UNITS * 1.2) {
-        fitTransactions.push(tx);
-      }
-    });
+  private dataToMempoolBlocks(transactionIds: string[], transactions: TransactionExtended[], totalSize: number, totalWeight: number, totalFees: number): MempoolBlockWithTransactions {
    const feeStats = Common.calcEffectiveFeeStatistics(transactions);
    return {
      blockSize: totalSize,
-      blockVSize: totalWeight / 4,
-      nTx: transactions.length,
-      totalFees: transactions.reduce((acc, cur) => acc + cur.fee, 0),
+      blockVSize: (totalWeight / 4), // fractional vsize to avoid rounding errors
+      nTx: transactionIds.length,
+      totalFees: totalFees,
      medianFee: feeStats.medianFee, // Common.percentile(transactions.map((tx) => tx.effectiveFeePerVsize), config.MEMPOOL.RECOMMENDED_FEE_PERCENTILE),
      feeRange: feeStats.feeRange, //Common.getFeesInRange(transactions, rangeLength),
-      transactionIds: transactions.map((tx) => tx.txid),
-      transactions: fitTransactions.map((tx) => Common.stripTransaction(tx)),
+      transactionIds: transactionIds,
+      transactions: transactions.map((tx) => Common.stripTransaction(tx)),
    };
  }
+
+  private resetUids(): void {
+    this.uidMap.clear();
+    this.nextUid = 1;
+  }
+
+  private setUid(tx: TransactionExtended): number {
+    const uid = this.nextUid;
+    this.nextUid++;
+    this.uidMap.set(uid, tx.txid);
+    tx.uid = uid;
+    return uid;
+  }
+
+  private getUid(tx: TransactionExtended): number | void {
+    if (tx?.uid != null && this.uidMap.has(tx.uid)) {
+      return tx.uid;
+    }
+  }
+
+  private removeUids(uids: number[]): void {
+    for (const uid of uids) {
+      this.uidMap.delete(uid);
+    }
+  }
+
+  private convertResultTxids({ blocks, rates, clusters }: { blocks: number[][], rates: Map<number, number>, clusters: Map<number, number[]>})
+    : { blocks: string[][], rates: { [root: string]: number }, clusters: { [root: string]: string[] }} {
+    const convertedBlocks: string[][] = blocks.map(block => block.map(uid => {
+      return this.uidMap.get(uid) || '';
+    }));
+    const convertedRates = {};
+    for (const rateUid of rates.keys()) {
+      const rateTxid = this.uidMap.get(rateUid);
+      if (rateTxid) {
+        convertedRates[rateTxid] = rates.get(rateUid);
+      }
+    }
+    const convertedClusters = {};
+    for (const rootUid of clusters.keys()) {
+      const rootTxid = this.uidMap.get(rootUid);
+      if (rootTxid) {
+        const members = clusters.get(rootUid)?.map(uid => {
+          return this.uidMap.get(uid);
+        });
+        convertedClusters[rootTxid] = members;
+      }
+    }
+    return { blocks: convertedBlocks, rates: convertedRates, clusters: convertedClusters } as { blocks: string[][], rates: { [root: string]: number }, clusters: { [root: string]: string[] }};
+  }
 }

 export default new MempoolBlocks();
--- a/backend/src/api/mempool.ts
+++ b/backend/src/api/mempool.ts
@@ -11,8 +11,6 @@ import bitcoinSecondClient from './bitcoin/bitcoin-second-client';
 import rbfCache from './rbf-cache';

 class Mempool {
-  private static WEBSOCKET_REFRESH_RATE_MS = 10000;
-  private static LAZY_DELETE_AFTER_SECONDS = 30;
  private inSync: boolean = false;
  private mempoolCacheDelta: number = -1;
  private mempoolCache: { [txId: string]: TransactionExtended } = {};
@@ -20,7 +18,7 @@ class Mempool {
                                                    maxmempool: 300000000, mempoolminfee: 0.00001000, minrelaytxfee: 0.00001000 };
  private mempoolChangedCallback: ((newMempool: {[txId: string]: TransactionExtended; }, newTransactions: TransactionExtended[],
    deletedTransactions: TransactionExtended[]) => void) | undefined;
-  private asyncMempoolChangedCallback: ((newMempool: {[txId: string]: TransactionExtended; }, newTransactions: TransactionExtended[],
+  private $asyncMempoolChangedCallback: ((newMempool: {[txId: string]: TransactionExtended; }, newTransactions: TransactionExtended[],
    deletedTransactions: TransactionExtended[]) => Promise<void>) | undefined;

  private txPerSecondArray: number[] = [];
@@ -35,6 +33,7 @@ class Mempool {
  private SAMPLE_TIME = 10000; // In ms
  private timer = new Date().getTime();
  private missingTxCount = 0;
+  private mainLoopTimeout: number = 120000;

  constructor() {
    setInterval(this.updateTxPerSecond.bind(this), 1000);
@@ -71,20 +70,20 @@ class Mempool {

  public setAsyncMempoolChangedCallback(fn: (newMempool: { [txId: string]: TransactionExtended; },
    newTransactions: TransactionExtended[], deletedTransactions: TransactionExtended[]) => Promise<void>) {
-    this.asyncMempoolChangedCallback = fn;
+    this.$asyncMempoolChangedCallback = fn;
  }

  public getMempool(): { [txid: string]: TransactionExtended } {
    return this.mempoolCache;
  }

-  public setMempool(mempoolData: { [txId: string]: TransactionExtended }) {
+  public async $setMempool(mempoolData: { [txId: string]: TransactionExtended }) {
    this.mempoolCache = mempoolData;
    if (this.mempoolChangedCallback) {
      this.mempoolChangedCallback(this.mempoolCache, [], []);
    }
-    if (this.asyncMempoolChangedCallback) {
-      this.asyncMempoolChangedCallback(this.mempoolCache, [], []);
+    if (this.$asyncMempoolChangedCallback) {
+      await this.$asyncMempoolChangedCallback(this.mempoolCache, [], []);
    }
  }

@@ -117,19 +116,23 @@ class Mempool {
    return txTimes;
  }

-  public async $updateMempool(): Promise<void> {
+  public async $updateMempool(transactions: string[]): Promise<void> {
    logger.debug(`Updating mempool...`);
+
+    // warn if this run stalls the main loop for more than 2 minutes
+    const timer = this.startTimer();
+
    const start = new Date().getTime();
    let hasChange: boolean = false;
    const currentMempoolSize = Object.keys(this.mempoolCache).length;
-    const transactions = await bitcoinApi.$getRawMempool();
+    this.updateTimerProgress(timer, 'got raw mempool');
    const diff = transactions.length - currentMempoolSize;
    const newTransactions: TransactionExtended[] = [];

    this.mempoolCacheDelta = Math.abs(diff);

    if (!this.inSync) {
-      loadingIndicators.setProgress('mempool', Object.keys(this.mempoolCache).length / transactions.length * 100);
+      loadingIndicators.setProgress('mempool', currentMempoolSize / transactions.length * 100);
    }

    // https://github.com/mempool/mempool/issues/3283
@@ -142,10 +145,12 @@ class Mempool {
      }
    };

+    let loggerTimer = new Date().getTime() / 1000;
    for (const txid of transactions) {
      if (!this.mempoolCache[txid]) {
        try {
          const transaction = await transactionUtils.$getTransactionExtended(txid);
+          this.updateTimerProgress(timer, 'fetched new transaction');
          this.mempoolCache[txid] = transaction;
          if (this.inSync) {
            this.txPerSecondArray.push(new Date().getTime());
@@ -163,9 +168,12 @@ class Mempool {
          logger.debug(`Error finding transaction '${txid}' in the mempool: ` + (e instanceof Error ? e.message : e));
        }
      }
-
-      if ((new Date().getTime()) - start > Mempool.WEBSOCKET_REFRESH_RATE_MS) {
-        break;
+      const elapsedSeconds = Math.round((new Date().getTime() / 1000) - loggerTimer);
+      if (elapsedSeconds > 4) {
+        const progress = (currentMempoolSize + newTransactions.length) / transactions.length * 100;
+        logger.debug(`Mempool is synchronizing. Processed ${newTransactions.length}/${diff} txs (${Math.round(progress)}%)`);
+        loadingIndicators.setProgress('mempool', progress);
+        loggerTimer = new Date().getTime() / 1000;
      }
    }

@@ -199,13 +207,15 @@ class Mempool {
      const transactionsObject = {};
      transactions.forEach((txId) => transactionsObject[txId] = true);

-      // Flag transactions for lazy deletion
+      // Delete evicted transactions from mempool
      for (const tx in this.mempoolCache) {
-        if (!transactionsObject[tx] && !this.mempoolCache[tx].deleteAfter) {
+        if (!transactionsObject[tx]) {
          deletedTransactions.push(this.mempoolCache[tx]);
-          this.mempoolCache[tx].deleteAfter = new Date().getTime() + Mempool.LAZY_DELETE_AFTER_SECONDS * 1000;
        }
      }
+      for (const tx of deletedTransactions) {
+        delete this.mempoolCache[tx.txid];
+      }
    }

    const newTransactionsStripped = newTransactions.map((tx) => Common.stripTransaction(tx));
@@ -222,22 +232,46 @@ class Mempool {
    if (this.mempoolChangedCallback && (hasChange || deletedTransactions.length)) {
      this.mempoolChangedCallback(this.mempoolCache, newTransactions, deletedTransactions);
    }
-    if (this.asyncMempoolChangedCallback && (hasChange || deletedTransactions.length)) {
-      await this.asyncMempoolChangedCallback(this.mempoolCache, newTransactions, deletedTransactions);
+    if (this.$asyncMempoolChangedCallback && (hasChange || deletedTransactions.length)) {
+      this.updateTimerProgress(timer, 'running async mempool callback');
+      await this.$asyncMempoolChangedCallback(this.mempoolCache, newTransactions, deletedTransactions);
+      this.updateTimerProgress(timer, 'completed async mempool callback');
    }

    const end = new Date().getTime();
    const time = end - start;
    logger.debug(`Mempool updated in ${time / 1000} seconds. New size: ${Object.keys(this.mempoolCache).length} (${diff > 0 ? '+' + diff : diff})`);
+
+    this.clearTimer(timer);
  }

-  public handleRbfTransactions(rbfTransactions: { [txid: string]: TransactionExtended; }) {
+  private startTimer() {
+    const state: any = {
+      start: Date.now(),
+      progress: 'begin $updateMempool',
+      timer: null,
+    };
+    state.timer = setTimeout(() => {
+      logger.err(`$updateMempool stalled at "${state.progress}"`);
+    }, this.mainLoopTimeout);
+    return state;
+  }
+
+  private updateTimerProgress(state, msg) {
+    state.progress = msg;
+  }
+
+  private clearTimer(state) {
+    if (state.timer) {
+      clearTimeout(state.timer);
+    }
+  }
+
+  public handleRbfTransactions(rbfTransactions: { [txid: string]: TransactionExtended[]; }): void {
    for (const rbfTransaction in rbfTransactions) {
-      if (this.mempoolCache[rbfTransaction]) {
+      if (this.mempoolCache[rbfTransaction] && rbfTransactions[rbfTransaction]?.length) {
        // Store replaced transactions
-        rbfCache.add(this.mempoolCache[rbfTransaction], rbfTransactions[rbfTransaction].txid);
-        // Erase the replaced transactions from the local mempool
-        delete this.mempoolCache[rbfTransaction];
+        rbfCache.add(rbfTransactions[rbfTransaction], this.mempoolCache[rbfTransaction]);
      }
    }
  }
@@ -255,17 +289,6 @@ class Mempool {
    }
  }

-  public deleteExpiredTransactions() {
-    const now = new Date().getTime();
-    for (const tx in this.mempoolCache) {
-      const lazyDeleteAt = this.mempoolCache[tx].deleteAfter;
-      if (lazyDeleteAt && lazyDeleteAt < now) {
-        delete this.mempoolCache[tx];
-        rbfCache.evict(tx);
-      }
-    }
-  }
-
  private $getMempoolInfo() {
    if (config.MEMPOOL.USE_SECOND_NODE_FOR_MINFEE) {
      return Promise.all([
--- a/backend/src/api/mining/mining.ts
+++ b/backend/src/api/mining/mining.ts
@@ -452,7 +452,7 @@ class Mining {
      const elapsedSeconds = Math.max(1, Math.round((new Date().getTime() / 1000) - timer));
      if (elapsedSeconds > 5) {
        const progress = Math.round(totalBlockChecked / blocks.length * 100);
-        logger.info(`Indexing difficulty adjustment at block #${block.height} | Progress: ${progress}%`, logger.tags.mining);
+        logger.debug(`Indexing difficulty adjustment at block #${block.height} | Progress: ${progress}%`, logger.tags.mining);
        timer = new Date().getTime() / 1000;
      }
    }
@@ -558,8 +558,10 @@ class Mining {
      currentBlockHeight -= 10000;
    }

-    if (totalIndexed) {
-      logger.info(`Indexing missing coinstatsindex data completed`, logger.tags.mining);
+    if (totalIndexed > 0) {
+      logger.info(`Indexing missing coinstatsindex data completed. Indexed ${totalIndexed}`, logger.tags.mining);
+    } else {
+      logger.debug(`Indexing missing coinstatsindex data completed. Indexed 0.`, logger.tags.mining);
    }
  }

--- a/backend/src/api/rbf-cache.ts
+++ b/backend/src/api/rbf-cache.ts
@@ -1,65 +1,341 @@
-import { TransactionExtended } from "../mempool.interfaces";
+import logger from "../logger";
+import { TransactionExtended, TransactionStripped } from "../mempool.interfaces";
+import bitcoinApi from './bitcoin/bitcoin-api-factory';
+import { Common } from "./common";
+
+interface RbfTransaction extends TransactionStripped {
+  rbf?: boolean;
+  mined?: boolean;
+}
+
+interface RbfTree {
+  tx: RbfTransaction;
+  time: number;
+  interval?: number;
+  mined?: boolean;
+  fullRbf: boolean;
+  replaces: RbfTree[];
+}

 class RbfCache {
-  private replacedBy: { [txid: string]: string; } = {};
-  private replaces: { [txid: string]: string[] } = {};
-  private txs: { [txid: string]: TransactionExtended } = {};
-  private expiring: { [txid: string]: Date } = {};
+  private replacedBy: Map<string, string> = new Map();
+  private replaces: Map<string, string[]> = new Map();
+  private rbfTrees: Map<string, RbfTree> = new Map(); // sequences of consecutive replacements
+  private dirtyTrees: Set<string> = new Set();
+  private treeMap: Map<string, string> = new Map(); // map of txids to sequence ids
+  private txs: Map<string, TransactionExtended> = new Map();
+  private expiring: Map<string, number> = new Map();

  constructor() {
-    setInterval(this.cleanup.bind(this), 1000 * 60 * 60);
+    setInterval(this.cleanup.bind(this), 1000 * 60 * 10);
  }

-  public add(replacedTx: TransactionExtended, newTxId: string): void {
-    this.replacedBy[replacedTx.txid] = newTxId;
-    this.txs[replacedTx.txid] = replacedTx;
-    if (!this.replaces[newTxId]) {
-      this.replaces[newTxId] = [];
+  public add(replaced: TransactionExtended[], newTxExtended: TransactionExtended): void {
+    if (!newTxExtended || !replaced?.length) {
+      return;
    }
-    this.replaces[newTxId].push(replacedTx.txid);
+
+    const newTx = Common.stripTransaction(newTxExtended) as RbfTransaction;
+    const newTime = newTxExtended.firstSeen || Date.now();
+    newTx.rbf = newTxExtended.vin.some((v) => v.sequence < 0xfffffffe);
+    this.txs.set(newTx.txid, newTxExtended);
+
+    // maintain rbf trees
+    let fullRbf = false;
+    const replacedTrees: RbfTree[] = [];
+    for (const replacedTxExtended of replaced) {
+      const replacedTx = Common.stripTransaction(replacedTxExtended) as RbfTransaction;
+      replacedTx.rbf = replacedTxExtended.vin.some((v) => v.sequence < 0xfffffffe);
+      this.replacedBy.set(replacedTx.txid, newTx.txid);
+      if (this.treeMap.has(replacedTx.txid)) {
+        const treeId = this.treeMap.get(replacedTx.txid);
+        if (treeId) {
+          const tree = this.rbfTrees.get(treeId);
+          this.rbfTrees.delete(treeId);
+          if (tree) {
+            tree.interval = newTime - tree?.time;
+            replacedTrees.push(tree);
+            fullRbf = fullRbf || tree.fullRbf;
+          }
+        }
+      } else {
+        const replacedTime = replacedTxExtended.firstSeen || Date.now();
+        replacedTrees.push({
+          tx: replacedTx,
+          time: replacedTime,
+          interval: newTime - replacedTime,
+          fullRbf: !replacedTx.rbf,
+          replaces: [],
+        });
+        fullRbf = fullRbf || !replacedTx.rbf;
+        this.txs.set(replacedTx.txid, replacedTxExtended);
+      }
+    }
+    const treeId = replacedTrees[0].tx.txid;
+    const newTree = {
+      tx: newTx,
+      time: newTxExtended.firstSeen || Date.now(),
+      fullRbf,
+      replaces: replacedTrees
+    };
+    this.rbfTrees.set(treeId, newTree);
+    this.updateTreeMap(treeId, newTree);
+    this.replaces.set(newTx.txid, replacedTrees.map(tree => tree.tx.txid));
+    this.dirtyTrees.add(treeId);
  }

  public getReplacedBy(txId: string): string | undefined {
-    return this.replacedBy[txId];
+    return this.replacedBy.get(txId);
  }

  public getReplaces(txId: string): string[] | undefined {
-    return this.replaces[txId];
+    return this.replaces.get(txId);
  }

  public getTx(txId: string): TransactionExtended | undefined {
-    return this.txs[txId];
+    return this.txs.get(txId);
+  }
+
+  public getRbfTree(txId: string): RbfTree | void {
+    return this.rbfTrees.get(this.treeMap.get(txId) || '');
+  }
+
+  // get a paginated list of RbfTrees
+  // ordered by most recent replacement time
+  public getRbfTrees(onlyFullRbf: boolean, after?: string): RbfTree[] {
+    const limit = 25;
+    const trees: RbfTree[] = [];
+    const used = new Set<string>();
+    const replacements: string[][] = Array.from(this.replacedBy).reverse();
+    const afterTree = after ? this.treeMap.get(after) : null;
+    let ready = !afterTree;
+    for (let i = 0; i < replacements.length && trees.length <= limit - 1; i++) {
+      const txid = replacements[i][1];
+      const treeId = this.treeMap.get(txid) || '';
+      if (treeId === afterTree) {
+        ready = true;
+      } else if (ready) {
+        if (!used.has(treeId)) {
+          const tree = this.rbfTrees.get(treeId);
+          used.add(treeId);
+          if (tree && (!onlyFullRbf || tree.fullRbf)) {
+            trees.push(tree);
+          }
+        }
+      }
+    }
+    return trees;
+  }
+
+  // get map of rbf trees that have been updated since the last call
+  public getRbfChanges(): { trees: {[id: string]: RbfTree }, map: { [txid: string]: string }} {
+    const changes: { trees: {[id: string]: RbfTree }, map: { [txid: string]: string }} = {
+      trees: {},
+      map: {},
+    };
+    this.dirtyTrees.forEach(id => {
+      const tree = this.rbfTrees.get(id);
+      if (tree) {
+        changes.trees[id] = tree;
+        this.getTransactionsInTree(tree).forEach(tx => {
+          changes.map[tx.txid] = id;
+        });
+      }
+    });
+    this.dirtyTrees = new Set();
+    return changes;
+  }
+
+  public mined(txid): void {
+    if (!this.txs.has(txid)) {
+      return;
+    }
+    const treeId = this.treeMap.get(txid);
+    if (treeId && this.rbfTrees.has(treeId)) {
+      const tree = this.rbfTrees.get(treeId);
+      if (tree) {
+        this.setTreeMined(tree, txid);
+        tree.mined = true;
+        this.dirtyTrees.add(treeId);
+      }
+    }
+    this.evict(txid);
  }

  // flag a transaction as removed from the mempool
-  public evict(txid): void {
-    this.expiring[txid] = new Date(Date.now() + 1000 * 86400); // 24 hours
+  public evict(txid: string, fast: boolean = false): void {
+    if (this.txs.has(txid) && (fast || !this.expiring.has(txid))) {
+      this.expiring.set(txid, fast ? Date.now() + (1000 * 60 * 10) : Date.now() + (1000 * 86400)); // 24 hours
+    }
  }

  private cleanup(): void {
-    const currentDate = new Date();
-    for (const txid in this.expiring) {
-      if (this.expiring[txid] < currentDate) {
-        delete this.expiring[txid];
+    const now = Date.now();
+    for (const txid of this.expiring.keys()) {
+      if ((this.expiring.get(txid) || 0) < now) {
+        this.expiring.delete(txid);
        this.remove(txid);
      }
    }
+    logger.debug(`rbf cache contains ${this.txs.size} txs, ${this.expiring.size} due to expire`);
  }

  // remove a transaction & all previous versions from the cache
  private remove(txid): void {
-    // don't remove a transaction while a newer version remains in the mempool
-    if (this.replaces[txid] && !this.replacedBy[txid]) {
-      const replaces = this.replaces[txid];
-      delete this.replaces[txid];
-      for (const tx of replaces) {
+    // don't remove a transaction if a newer version remains in the mempool
+    if (!this.replacedBy.has(txid)) {
+      const replaces = this.replaces.get(txid);
+      this.replaces.delete(txid);
+      this.treeMap.delete(txid);
+      this.txs.delete(txid);
+      this.expiring.delete(txid);
+      for (const tx of (replaces || [])) {
        // recursively remove prior versions from the cache
-        delete this.replacedBy[tx];
-        delete this.txs[tx];
+        this.replacedBy.delete(tx);
+        // if this is the id of a tree, remove that too
+        if (this.treeMap.get(tx) === tx) {
+          this.rbfTrees.delete(tx);
+        }
        this.remove(tx);
      }
    }
  }
+
+  private updateTreeMap(newId: string, tree: RbfTree): void {
+    this.treeMap.set(tree.tx.txid, newId);
+    tree.replaces.forEach(subtree => {
+      this.updateTreeMap(newId, subtree);
+    });
+  }
+
+  private getTransactionsInTree(tree: RbfTree, txs: RbfTransaction[] = []): RbfTransaction[] {
+    txs.push(tree.tx);
+    tree.replaces.forEach(subtree => {
+      this.getTransactionsInTree(subtree, txs);
+    });
+    return txs;
+  }
+
+  private setTreeMined(tree: RbfTree, txid: string): void {
+    if (tree.tx.txid === txid) {
+      tree.tx.mined = true;
+    } else {
+      tree.replaces.forEach(subtree => {
+        this.setTreeMined(subtree, txid);
+      });
+    }
+  }
+
+  public dump(): any {
+    const trees = Array.from(this.rbfTrees.values()).map((tree: RbfTree) => { return this.exportTree(tree); });
+
+    return {
+      txs: Array.from(this.txs.entries()),
+      trees,
+      expiring: Array.from(this.expiring.entries()),
+    };
+  }
+
+  public async load({ txs, trees, expiring }): Promise<void> {
+    txs.forEach(txEntry => {
+      this.txs.set(txEntry[0], txEntry[1]);
+    });
+    for (const deflatedTree of trees) {
+      await this.importTree(deflatedTree.root, deflatedTree.root, deflatedTree, this.txs);
+    }
+    expiring.forEach(expiringEntry => {
+      if (this.txs.has(expiringEntry[0])) {
+        this.expiring.set(expiringEntry[0], new Date(expiringEntry[1]).getTime());
+      }
+    });
+    this.cleanup();
+  }
+
+  exportTree(tree: RbfTree, deflated: any = null) {
+    if (!deflated) {
+      deflated = {
+        root: tree.tx.txid,
+      };
+    }
+    deflated[tree.tx.txid] = {
+      tx: tree.tx.txid,
+      txMined: tree.tx.mined,
+      time: tree.time,
+      interval: tree.interval,
+      mined: tree.mined,
+      fullRbf: tree.fullRbf,
+      replaces: tree.replaces.map(child => child.tx.txid),
+    };
+    tree.replaces.forEach(child => {
+      this.exportTree(child, deflated);
+    });
+    return deflated;
+  }
+
+  async importTree(root, txid, deflated, txs: Map<string, TransactionExtended>, mined: boolean = false): Promise<RbfTree | void> {
+    const treeInfo = deflated[txid];
+    const replaces: RbfTree[] = [];
+
+    // check if any transactions in this tree have already been confirmed
+    mined = mined || treeInfo.mined;
+    let exists = mined;
+    if (!mined) {
+      try {
+        const apiTx = await bitcoinApi.$getRawTransaction(txid);
+        if (apiTx) {
+          exists = true;
+        }
+        if (apiTx?.status?.confirmed) {
+          mined = true;
+          treeInfo.txMined = true;
+          this.evict(txid, true);
+        }
+      } catch (e) {
+        // most transactions do not exist
+      }
+    }
+
+    // if the root tx is not in the mempool or the blockchain
+    // evict this tree as soon as possible
+    if (root === txid && !exists) {
+      this.evict(txid, true);
+    }
+
+    // recursively reconstruct child trees
+    for (const childId of treeInfo.replaces) {
+      const replaced = await this.importTree(root, childId, deflated, txs, mined);
+      if (replaced) {
+        this.replacedBy.set(replaced.tx.txid, txid);
+        replaces.push(replaced);
+        if (replaced.mined) {
+          mined = true;
+        }
+      }
+    }
+    this.replaces.set(txid, replaces.map(t => t.tx.txid));
+
+    const tx = txs.get(txid);
+    if (!tx) {
+      return;
+    }
+    const strippedTx = Common.stripTransaction(tx) as RbfTransaction;
+    strippedTx.rbf = tx.vin.some((v) => v.sequence < 0xfffffffe);
+    strippedTx.mined = treeInfo.txMined;
+    const tree = {
+      tx: strippedTx,
+      time: treeInfo.time,
+      interval: treeInfo.interval,
+      mined: mined,
+      fullRbf: treeInfo.fullRbf,
+      replaces,
+    };
+    this.treeMap.set(txid, root);
+    if (root === txid) {
+      this.rbfTrees.set(root, tree);
+      this.dirtyTrees.add(root);
+    }
+    return tree;
+  }
 }

 export default new RbfCache();
--- a/backend/src/api/tx-selection-worker.ts
+++ b/backend/src/api/tx-selection-worker.ts
@@ -1,11 +1,10 @@
 import config from '../config';
 import logger from '../logger';
-import { ThreadTransaction, MempoolBlockWithTransactions, AuditTransaction } from '../mempool.interfaces';
+import { CompactThreadTransaction, AuditTransaction } from '../mempool.interfaces';
 import { PairingHeap } from '../utils/pairing-heap';
-import { Common } from './common';
 import { parentPort } from 'worker_threads';

-let mempool: { [txid: string]: ThreadTransaction } = {};
+let mempool: Map<number, CompactThreadTransaction> = new Map();

 if (parentPort) {
  parentPort.on('message', (params) => {
@@ -13,18 +12,18 @@ if (parentPort) {
      mempool = params.mempool;
    } else if (params.type === 'update') {
      params.added.forEach(tx => {
-        mempool[tx.txid] = tx;
+        mempool.set(tx.uid, tx);
      });
-      params.removed.forEach(txid => {
-        delete mempool[txid];
+      params.removed.forEach(uid => {
+        mempool.delete(uid);
      });
    }
    
-    const { blocks, clusters } = makeBlockTemplates(mempool);
+    const { blocks, rates, clusters } = makeBlockTemplates(mempool);

    // return the result to main thread.
    if (parentPort) {
-     parentPort.postMessage({ blocks, clusters });
+      parentPort.postMessage({ blocks, rates, clusters });
    }
  });
 }
@@ -33,26 +32,25 @@ if (parentPort) {
 * Build projected mempool blocks using an approximation of the transaction selection algorithm from Bitcoin Core
 * (see BlockAssembler in https://github.com/bitcoin/bitcoin/blob/master/src/node/miner.cpp)
 */
-function makeBlockTemplates(mempool: { [txid: string]: ThreadTransaction })
-  : { blocks: ThreadTransaction[][], clusters: { [root: string]: string[] } } {
+function makeBlockTemplates(mempool: Map<number, CompactThreadTransaction>)
+  : { blocks: number[][], rates: Map<number, number>, clusters: Map<number, number[]> } {
  const start = Date.now();
-  const auditPool: { [txid: string]: AuditTransaction } = {};
+  const auditPool: Map<number, AuditTransaction> = new Map();
  const mempoolArray: AuditTransaction[] = [];
-  const restOfArray: ThreadTransaction[] = [];
-  const cpfpClusters: { [root: string]: string[] } = {};
+  const cpfpClusters: Map<number, number[]> = new Map();
  
-  // grab the top feerate txs up to maxWeight
-  Object.values(mempool).sort((a, b) => b.feePerVsize - a.feePerVsize).forEach(tx => {
+  mempool.forEach(tx => {
+    tx.dirty = false;
    // initializing everything up front helps V8 optimize property access later
-    auditPool[tx.txid] = {
-      txid: tx.txid,
+    auditPool.set(tx.uid, {
+      uid: tx.uid,
      fee: tx.fee,
      weight: tx.weight,
      feePerVsize: tx.feePerVsize,
      effectiveFeePerVsize: tx.feePerVsize,
-      vin: tx.vin,
+      inputs: tx.inputs || [],
      relativesSet: false,
-      ancestorMap: new Map<string, AuditTransaction>(),
+      ancestorMap: new Map<number, AuditTransaction>(),
      children: new Set<AuditTransaction>(),
      ancestorFee: 0,
      ancestorWeight: 0,
@@ -60,8 +58,8 @@ function makeBlockTemplates(mempool: { [txid: string]: ThreadTransaction })
      used: false,
      modified: false,
      modifiedNode: null,
-    };
-    mempoolArray.push(auditPool[tx.txid]);
+    });
+    mempoolArray.push(auditPool.get(tx.uid) as AuditTransaction);
  });

  // Build relatives graph & calculate ancestor scores
@@ -72,15 +70,28 @@ function makeBlockTemplates(mempool: { [txid: string]: ThreadTransaction })
  }

  // Sort by descending ancestor score
-  mempoolArray.sort((a, b) => (b.score || 0) - (a.score || 0));
+  mempoolArray.sort((a, b) => {
+    if (b.score === a.score) {
+      // tie-break by uid for stability
+      return a.uid < b.uid ? -1 : 1;
+    } else {
+      return (b.score || 0) - (a.score || 0);
+    }
+  });

  // Build blocks by greedily choosing the highest feerate package
  // (i.e. the package rooted in the transaction with the best ancestor score)
-  const blocks: ThreadTransaction[][] = [];
+  const blocks: number[][] = [];
  let blockWeight = 4000;
-  let blockSize = 0;
  let transactions: AuditTransaction[] = [];
-  const modified: PairingHeap<AuditTransaction> = new PairingHeap((a, b): boolean => (a.score || 0) > (b.score || 0));
+  const modified: PairingHeap<AuditTransaction> = new PairingHeap((a, b): boolean => {
+    if (a.score === b.score) {
+      // tie-break by uid for stability
+      return a.uid > b.uid;
+    } else {
+      return (a.score || 0) > (b.score || 0);
+    }
+  });
  let overflow: AuditTransaction[] = [];
  let failures = 0;
  let top = 0;
@@ -107,30 +118,36 @@ function makeBlockTemplates(mempool: { [txid: string]: ThreadTransaction })

    if (nextTx && !nextTx?.used) {
      // Check if the package fits into this block
-      if (blockWeight + nextTx.ancestorWeight < config.MEMPOOL.BLOCK_WEIGHT_UNITS) {
+      if (blocks.length >= 7 || (blockWeight + nextTx.ancestorWeight < config.MEMPOOL.BLOCK_WEIGHT_UNITS)) {
        const ancestors: AuditTransaction[] = Array.from(nextTx.ancestorMap.values());
        // sort ancestors by dependency graph (equivalent to sorting by ascending ancestor count)
        const sortedTxSet = [...ancestors.sort((a, b) => { return (a.ancestorMap.size || 0) - (b.ancestorMap.size || 0); }), nextTx];
        let isCluster = false;
        if (sortedTxSet.length > 1) {
-          cpfpClusters[nextTx.txid] = sortedTxSet.map(tx => tx.txid);
+          cpfpClusters.set(nextTx.uid, sortedTxSet.map(tx => tx.uid));
          isCluster = true;
        }
        const effectiveFeeRate = nextTx.ancestorFee / (nextTx.ancestorWeight / 4);
        const used: AuditTransaction[] = [];
        while (sortedTxSet.length) {
          const ancestor = sortedTxSet.pop();
-          const mempoolTx = mempool[ancestor.txid];
+          const mempoolTx = mempool.get(ancestor.uid);
+          if (!mempoolTx) {
+            continue;
+          }
          ancestor.used = true;
-          ancestor.usedBy = nextTx.txid;
+          ancestor.usedBy = nextTx.uid;
          // update original copy of this tx with effective fee rate & relatives data
-          mempoolTx.effectiveFeePerVsize = effectiveFeeRate;
-          if (isCluster) {
-            mempoolTx.cpfpRoot = nextTx.txid;
+          if (mempoolTx.effectiveFeePerVsize !== effectiveFeeRate) {
+            mempoolTx.effectiveFeePerVsize = effectiveFeeRate;
+            mempoolTx.dirty = true;
+          }
+          if (mempoolTx.cpfpRoot !== nextTx.uid) {
+            mempoolTx.cpfpRoot = isCluster ? nextTx.uid : null;
+            mempoolTx.dirty;
          }
          mempoolTx.cpfpChecked = true;
          transactions.push(ancestor);
-          blockSize += ancestor.size;
          blockWeight += ancestor.weight;
          used.push(ancestor);
        }
@@ -156,11 +173,10 @@ function makeBlockTemplates(mempool: { [txid: string]: ThreadTransaction })
    if ((exceededPackageTries || queueEmpty) && blocks.length < 7) {
      // construct this block
      if (transactions.length) {
-        blocks.push(transactions.map(t => mempool[t.txid]));
+        blocks.push(transactions.map(t => t.uid));
      }
      // reset for the next block
      transactions = [];
-      blockSize = 0;
      blockWeight = 4000;

      // 'overflow' packages didn't fit in this block, but are valid candidates for the next
@@ -175,50 +191,38 @@ function makeBlockTemplates(mempool: { [txid: string]: ThreadTransaction })
      overflow = [];
    }
  }
-  // pack any leftover transactions into the last block
-  for (const tx of overflow) {
-    if (!tx || tx?.used) {
-      continue;
-    }
-    blockWeight += tx.weight;
-    const mempoolTx = mempool[tx.txid];
-    // update original copy of this tx with effective fee rate & relatives data
-    mempoolTx.effectiveFeePerVsize = tx.score;
-    if (tx.ancestorMap.size > 0) {
-      cpfpClusters[tx.txid] = Array.from(tx.ancestorMap?.values()).map(a => a.txid);
-      mempoolTx.cpfpRoot = tx.txid;
-    }
-    mempoolTx.cpfpChecked = true;
-    transactions.push(tx);
-    tx.used = true;
+
+  if (overflow.length > 0) {
+    logger.warn('GBT overflow list unexpectedly non-empty after final block constructed');
  }
-  const blockTransactions = transactions.map(t => mempool[t.txid]);
-  restOfArray.forEach(tx => {
-    blockWeight += tx.weight;
-    tx.effectiveFeePerVsize = tx.feePerVsize;
-    tx.cpfpChecked = false;
-    blockTransactions.push(tx);
-  });
-  if (blockTransactions.length) {
-    blocks.push(blockTransactions);
+  // add the final unbounded block if it contains any transactions
+  if (transactions.length > 0) {
+    blocks.push(transactions.map(t => t.uid));
+  }
+
+  // get map of dirty transactions
+  const rates = new Map<number, number>();
+  for (const tx of mempool.values()) {
+    if (tx?.dirty) {
+      rates.set(tx.uid, tx.effectiveFeePerVsize || tx.feePerVsize);
+    }
  }
-  transactions = [];

  const end = Date.now();
  const time = end - start;
  logger.debug('Mempool templates calculated in ' + time / 1000 + ' seconds');

-  return { blocks, clusters: cpfpClusters };
+  return { blocks, rates, clusters: cpfpClusters };
 }

 // traverse in-mempool ancestors
 // recursion unavoidable, but should be limited to depth < 25 by mempool policy
 function setRelatives(
  tx: AuditTransaction,
-  mempool: { [txid: string]: AuditTransaction },
+  mempool: Map<number, AuditTransaction>,
 ): void {
-  for (const parent of tx.vin) {
-    const parentTx = mempool[parent];
+  for (const parent of tx.inputs) {
+    const parentTx = mempool.get(parent);
    if (parentTx && !tx.ancestorMap?.has(parent)) {
      tx.ancestorMap.set(parent, parentTx);
      parentTx.children.add(tx);
@@ -227,7 +231,7 @@ function setRelatives(
        setRelatives(parentTx, mempool);
      }
      parentTx.ancestorMap.forEach((ancestor) => {
-        tx.ancestorMap.set(ancestor.txid, ancestor);
+        tx.ancestorMap.set(ancestor.uid, ancestor);
      });
    }
  };
@@ -245,7 +249,7 @@ function setRelatives(
 // avoids recursion to limit call stack depth
 function updateDescendants(
  rootTx: AuditTransaction,
-  mempool: { [txid: string]: AuditTransaction },
+  mempool: Map<number, AuditTransaction>,
  modified: PairingHeap<AuditTransaction>,
 ): void {
  const descendantSet: Set<AuditTransaction> = new Set();
@@ -261,9 +265,9 @@ function updateDescendants(
  });
  while (descendants.length) {
    descendantTx = descendants.pop();
-    if (descendantTx && descendantTx.ancestorMap && descendantTx.ancestorMap.has(rootTx.txid)) {
+    if (descendantTx && descendantTx.ancestorMap && descendantTx.ancestorMap.has(rootTx.uid)) {
      // remove tx as ancestor
-      descendantTx.ancestorMap.delete(rootTx.txid);
+      descendantTx.ancestorMap.delete(rootTx.uid);
      descendantTx.ancestorFee -= rootTx.fee;
      descendantTx.ancestorWeight -= rootTx.weight;
      tmpScore = descendantTx.score;
--- a/backend/src/api/websocket-handler.ts
+++ b/backend/src/api/websocket-handler.ts
@@ -26,6 +26,13 @@ class WebsocketHandler {
  private wss: WebSocket.Server | undefined;
  private extraInitProperties = {};

+  private numClients = 0;
+  private numConnected = 0;
+  private numDisconnected = 0;
+
+  private initData: { [key: string]: string } = {};
+  private serializedInitData: string = '{}';
+
  constructor() { }

  setWebsocketServer(wss: WebSocket.Server) {
@@ -34,6 +41,41 @@ class WebsocketHandler {

  setExtraInitProperties(property: string, value: any) {
    this.extraInitProperties[property] = value;
+    this.setInitDataFields(this.extraInitProperties);
+  }
+
+  private setInitDataFields(data: { [property: string]: any }): void {
+    for (const property of Object.keys(data)) {
+      if (data[property] != null) {
+        this.initData[property] = JSON.stringify(data[property]);
+      } else {
+        delete this.initData[property];
+      }
+    }
+    this.serializedInitData = '{'
+      + Object.keys(this.initData).map(key => `"${key}": ${this.initData[key]}`).join(', ')
+      + '}';
+  }
+
+  private updateInitData(): void {
+    const _blocks = blocks.getBlocks().slice(-config.MEMPOOL.INITIAL_BLOCKS_AMOUNT);
+    const da = difficultyAdjustment.getDifficultyAdjustment();
+    this.setInitDataFields({
+      'mempoolInfo': memPool.getMempoolInfo(),
+      'vBytesPerSecond': memPool.getVBytesPerSecond(),
+      'blocks': _blocks,
+      'conversions': priceUpdater.getLatestPrices(),
+      'mempool-blocks': mempoolBlocks.getMempoolBlocks(),
+      'transactions': memPool.getLatestTransactions(),
+      'backendInfo': backendInfo.getBackendInfo(),
+      'loadingIndicators': loadingIndicators.getLoadingIndicators(),
+      'da': da?.previousTime ? da : undefined,
+      'fees': feeApi.getRecommendedFee(),
+    });
+  }
+
+  public getSerializedInitData(): string {
+    return this.serializedInitData;
  }

  setupConnectionHandling() {
@@ -42,7 +84,11 @@ class WebsocketHandler {
    }

    this.wss.on('connection', (client: WebSocket) => {
+      this.numConnected++;
      client.on('error', logger.info);
+      client.on('close', () => {
+        this.numDisconnected++;
+      });
      client.on('message', async (message: string) => {
        try {
          const parsedMessage: WebsocketResponse = JSON.parse(message);
@@ -58,9 +104,10 @@ class WebsocketHandler {
          if (parsedMessage && parsedMessage['track-tx']) {
            if (/^[a-fA-F0-9]{64}$/.test(parsedMessage['track-tx'])) {
              client['track-tx'] = parsedMessage['track-tx'];
+              const trackTxid = client['track-tx'];
              // Client is telling the transaction wasn't found
              if (parsedMessage['watch-mempool']) {
-                const rbfCacheTxid = rbfCache.getReplacedBy(client['track-tx']);
+                const rbfCacheTxid = rbfCache.getReplacedBy(trackTxid);
                if (rbfCacheTxid) {
                  response['txReplaced'] = {
                    txid: rbfCacheTxid,
@@ -68,7 +115,7 @@ class WebsocketHandler {
                  client['track-tx'] = null;
                } else {
                  // It might have appeared before we had the time to start watching for it
-                  const tx = memPool.getMempool()[client['track-tx']];
+                  const tx = memPool.getMempool()[trackTxid];
                  if (tx) {
                    if (config.MEMPOOL.BACKEND === 'esplora') {
                      response['tx'] = tx;
@@ -92,6 +139,13 @@ class WebsocketHandler {
                  }
                }
              }
+              const tx = memPool.getMempool()[trackTxid];
+              if (tx && tx.position) {
+                response['txPosition'] = {
+                  txid: trackTxid,
+                  position: tx.position,
+                };
+              }
            } else {
              client['track-tx'] = null;
            }
@@ -132,12 +186,22 @@ class WebsocketHandler {
            }
          }

+          if (parsedMessage && parsedMessage['track-rbf'] !== undefined) {
+            if (['all', 'fullRbf'].includes(parsedMessage['track-rbf'])) {
+              client['track-rbf'] = parsedMessage['track-rbf'];
+            } else {
+              client['track-rbf'] = false;
+            }
+          }
+
          if (parsedMessage.action === 'init') {
-            const _blocks = blocks.getBlocks().slice(-config.MEMPOOL.INITIAL_BLOCKS_AMOUNT);
-            if (!_blocks) {
+            if (!this.initData['blocks']?.length || !this.initData['da']) {
+              this.updateInitData();
+            }
+            if (!this.initData['blocks']?.length) {
              return;
            }
-            client.send(JSON.stringify(this.getInitData(_blocks)));
+            client.send(this.serializedInitData);
          }

          if (parsedMessage.action === 'ping') {
@@ -186,11 +250,14 @@ class WebsocketHandler {
      throw new Error('WebSocket.Server is not set');
    }

+    this.setInitDataFields({ 'loadingIndicators': indicators });
+
+    const response = JSON.stringify({ loadingIndicators: indicators });
    this.wss.clients.forEach((client) => {
      if (client.readyState !== WebSocket.OPEN) {
        return;
      }
-      client.send(JSON.stringify({ loadingIndicators: indicators }));
+      client.send(response);
    });
  }

@@ -199,39 +266,28 @@ class WebsocketHandler {
      throw new Error('WebSocket.Server is not set');
    }

+    this.setInitDataFields({ 'conversions': conversionRates });
+
+    const response = JSON.stringify({ conversions: conversionRates });
    this.wss.clients.forEach((client) => {
      if (client.readyState !== WebSocket.OPEN) {
        return;
      }
-      client.send(JSON.stringify({ conversions: conversionRates }));
+      client.send(response);
    });
  }

-  getInitData(_blocks?: BlockExtended[]) {
-    if (!_blocks) {
-      _blocks = blocks.getBlocks().slice(-config.MEMPOOL.INITIAL_BLOCKS_AMOUNT);
-    }
-    const da = difficultyAdjustment.getDifficultyAdjustment();
-    return {
-      'mempoolInfo': memPool.getMempoolInfo(),
-      'vBytesPerSecond': memPool.getVBytesPerSecond(),
-      'blocks': _blocks,
-      'conversions': priceUpdater.getLatestPrices(),
-      'mempool-blocks': mempoolBlocks.getMempoolBlocks(),
-      'transactions': memPool.getLatestTransactions(),
-      'backendInfo': backendInfo.getBackendInfo(),
-      'loadingIndicators': loadingIndicators.getLoadingIndicators(),
-      'da': da?.previousTime ? da : undefined,
-      'fees': feeApi.getRecommendedFee(),
-      ...this.extraInitProperties
-    };
-  }
-
  handleNewStatistic(stats: OptimizedStatistic) {
    if (!this.wss) {
      throw new Error('WebSocket.Server is not set');
    }

+    this.printLogs();
+
+    const response = JSON.stringify({
+      'live-2h-chart': stats
+    });
+
    this.wss.clients.forEach((client) => {
      if (client.readyState !== WebSocket.OPEN) {
        return;
@@ -241,20 +297,20 @@ class WebsocketHandler {
        return;
      }

-      client.send(JSON.stringify({
-        'live-2h-chart': stats
-      }));
+      client.send(response);
    });
  }

-  async handleMempoolChange(newMempool: { [txid: string]: TransactionExtended },
+  async $handleMempoolChange(newMempool: { [txid: string]: TransactionExtended },
    newTransactions: TransactionExtended[], deletedTransactions: TransactionExtended[]): Promise<void> {
    if (!this.wss) {
      throw new Error('WebSocket.Server is not set');
    }

+    this.printLogs();
+
    if (config.MEMPOOL.ADVANCED_GBT_MEMPOOL) {
-      await mempoolBlocks.updateBlockTemplates(newMempool, newTransactions, deletedTransactions.map(tx => tx.txid), true);
+      await mempoolBlocks.$updateBlockTemplates(newMempool, newTransactions, deletedTransactions, true);
    } else {
      mempoolBlocks.updateMempoolBlocks(newMempool, true);
    }
@@ -266,8 +322,55 @@ class WebsocketHandler {
    const rbfTransactions = Common.findRbfTransactions(newTransactions, deletedTransactions);
    const da = difficultyAdjustment.getDifficultyAdjustment();
    memPool.handleRbfTransactions(rbfTransactions);
+    const rbfChanges = rbfCache.getRbfChanges();
+    let rbfReplacements;
+    let fullRbfReplacements;
+    if (Object.keys(rbfChanges.trees).length) {
+      rbfReplacements = rbfCache.getRbfTrees(false);
+      fullRbfReplacements = rbfCache.getRbfTrees(true);
+    }
+    for (const deletedTx of deletedTransactions) {
+      rbfCache.evict(deletedTx.txid);
+    }
    const recommendedFees = feeApi.getRecommendedFee();

+    // update init data
+    this.updateInitData();
+
+    // cache serialized objects to avoid stringify-ing the same thing for every client
+    const responseCache = { ...this.initData };
+    function getCachedResponse(key: string,  data): string {
+      if (!responseCache[key]) {
+        responseCache[key] = JSON.stringify(data);
+      }
+      return responseCache[key];
+    }
+
+    // pre-compute new tracked outspends
+    const outspendCache: { [txid: string]: { [vout: number]: { vin: number, txid: string } } } = {};
+    const trackedTxs = new Set<string>();
+    this.wss.clients.forEach((client) => {
+      if (client['track-tx']) {
+        trackedTxs.add(client['track-tx']);
+      }
+    });
+    if (trackedTxs.size > 0) {
+      for (const tx of newTransactions) {
+        for (let i = 0; i < tx.vin.length; i++) {
+          const vin = tx.vin[i];
+          if (trackedTxs.has(vin.txid)) {
+            if (!outspendCache[vin.txid]) {
+              outspendCache[vin.txid] = { [vin.vout]: { vin: i, txid: tx.txid }};
+            } else {
+              outspendCache[vin.txid][vin.vout] = { vin: i, txid: tx.txid };
+            }
+          }
+        }
+      }
+    }
+
+    const latestTransactions = newTransactions.slice(0, 6).map((tx) => Common.stripTransaction(tx));
+
    this.wss.clients.forEach(async (client) => {
      if (client.readyState !== WebSocket.OPEN) {
        return;
@@ -276,17 +379,17 @@ class WebsocketHandler {
      const response = {};

      if (client['want-stats']) {
-        response['mempoolInfo'] = mempoolInfo;
-        response['vBytesPerSecond'] = vBytesPerSecond;
-        response['transactions'] = newTransactions.slice(0, 6).map((tx) => Common.stripTransaction(tx));
+        response['mempoolInfo'] = getCachedResponse('mempoolInfo', mempoolInfo);
+        response['vBytesPerSecond'] = getCachedResponse('vBytesPerSecond', vBytesPerSecond);
+        response['transactions'] = getCachedResponse('transactions', latestTransactions);
        if (da?.previousTime) {
-          response['da'] = da;
+          response['da'] = getCachedResponse('da', da);
        }
-        response['fees'] = recommendedFees;
+        response['fees'] = getCachedResponse('fees', recommendedFees);
      }

      if (client['want-mempool-blocks']) {
-        response['mempool-blocks'] = mBlocks;
+        response['mempool-blocks'] = getCachedResponse('mempool-blocks', mBlocks);
      }

      if (client['track-mempool-tx']) {
@@ -295,12 +398,12 @@ class WebsocketHandler {
          if (config.MEMPOOL.BACKEND !== 'esplora') {
            try {
              const fullTx = await transactionUtils.$getTransactionExtended(tx.txid, true);
-              response['tx'] = fullTx;
+              response['tx'] = JSON.stringify(fullTx);
            } catch (e) {
              logger.debug('Error finding transaction in mempool: ' + (e instanceof Error ? e.message : e));
            }
          } else {
-            response['tx'] = tx;
+            response['tx'] = JSON.stringify(tx);
          }
          client['track-mempool-tx'] = null;
        }
@@ -340,7 +443,7 @@ class WebsocketHandler {
        }

        if (foundTransactions.length) {
-          response['address-transactions'] = foundTransactions;
+          response['address-transactions'] = JSON.stringify(foundTransactions);
        }
      }

@@ -369,49 +472,60 @@ class WebsocketHandler {
        });

        if (foundTransactions.length) {
-          response['address-transactions'] = foundTransactions;
+          response['address-transactions'] = JSON.stringify(foundTransactions);
        }
      }

      if (client['track-tx']) {
-        const outspends: object = {};
-        newTransactions.forEach((tx) => tx.vin.forEach((vin, i) => {
-          if (vin.txid === client['track-tx']) {
-            outspends[vin.vout] = {
-              vin: i,
-              txid: tx.txid,
-            };
-          }
-        }));
+        const trackTxid = client['track-tx'];
+        const outspends = outspendCache[trackTxid];

-        if (Object.keys(outspends).length) {
-          response['utxoSpent'] = outspends;
+        if (outspends && Object.keys(outspends).length) {
+          response['utxoSpent'] = JSON.stringify(outspends);
        }

-        if (rbfTransactions[client['track-tx']]) {
-          for (const rbfTransaction in rbfTransactions) {
-            if (client['track-tx'] === rbfTransaction) {
-              response['rbfTransaction'] = {
-                txid: rbfTransactions[rbfTransaction].txid,
-              };
-              break;
-            }
-          }
+        const rbfReplacedBy = rbfCache.getReplacedBy(client['track-tx']);
+        if (rbfReplacedBy) {
+          response['rbfTransaction'] = JSON.stringify({
+            txid: rbfReplacedBy,
+          })
+        }
+
+        const rbfChange = rbfChanges.map[client['track-tx']];
+        if (rbfChange) {
+          response['rbfInfo'] = JSON.stringify(rbfChanges.trees[rbfChange]);
+        }
+
+        const mempoolTx = newMempool[trackTxid];
+        if (mempoolTx && mempoolTx.position) {
+          response['txPosition'] = JSON.stringify({
+            txid: trackTxid,
+            position: mempoolTx.position,
+          });
        }
      }

      if (client['track-mempool-block'] >= 0) {
        const index = client['track-mempool-block'];
        if (mBlockDeltas[index]) {
-          response['projected-block-transactions'] = {
+          response['projected-block-transactions'] = getCachedResponse(`projected-block-transactions-${index}`, {
            index: index,
            delta: mBlockDeltas[index],
-          };
+          });
        }
      }

+      if (client['track-rbf'] === 'all' && rbfReplacements) {
+        response['rbfLatest'] = getCachedResponse('rbfLatest', rbfReplacements);
+      } else if (client['track-rbf'] === 'fullRbf' && fullRbfReplacements) {
+        response['rbfLatest'] = getCachedResponse('fullrbfLatest', fullRbfReplacements);
+      }
+
      if (Object.keys(response).length) {
-        client.send(JSON.stringify(response));
+        const serializedResponse = '{'
+          + Object.keys(response).map(key => `"${key}": ${response[key]}`).join(', ')
+          + '}';
+        client.send(serializedResponse);
      }
    });
  }
@@ -421,17 +535,25 @@ class WebsocketHandler {
      throw new Error('WebSocket.Server is not set');
    }

+    this.printLogs();
+
    const _memPool = memPool.getMempool();

    if (config.MEMPOOL.AUDIT) {
      let projectedBlocks;
+      let auditMempool = _memPool;
      // template calculation functions have mempool side effects, so calculate audits using
      // a cloned copy of the mempool if we're running a different algorithm for mempool updates
-      const auditMempool = (config.MEMPOOL.ADVANCED_GBT_AUDIT === config.MEMPOOL.ADVANCED_GBT_MEMPOOL) ? _memPool : deepClone(_memPool);
-      if (config.MEMPOOL.ADVANCED_GBT_AUDIT) {
-        projectedBlocks = await mempoolBlocks.makeBlockTemplates(auditMempool, false);
+      const separateAudit = config.MEMPOOL.ADVANCED_GBT_AUDIT !== config.MEMPOOL.ADVANCED_GBT_MEMPOOL;
+      if (separateAudit) {
+        auditMempool = deepClone(_memPool);
+        if (config.MEMPOOL.ADVANCED_GBT_AUDIT) {
+          projectedBlocks = await mempoolBlocks.$makeBlockTemplates(auditMempool, false);
+        } else {
+          projectedBlocks = mempoolBlocks.updateMempoolBlocks(auditMempool, false);
+        }
      } else {
-        projectedBlocks = mempoolBlocks.updateMempoolBlocks(auditMempool, false);
+        projectedBlocks = mempoolBlocks.getMempoolBlocksWithTransactions();
      }

      if (Common.indexingEnabled() && memPool.isInSync()) {
@@ -477,16 +599,14 @@ class WebsocketHandler {
      }
    }

-    const removed: string[] = [];
    // Update mempool to remove transactions included in the new block
    for (const txId of txIds) {
      delete _memPool[txId];
-      removed.push(txId);
-      rbfCache.evict(txId);
+      rbfCache.mined(txId);
    }

    if (config.MEMPOOL.ADVANCED_GBT_MEMPOOL) {
-      await mempoolBlocks.updateBlockTemplates(_memPool, [], removed, true);
+      await mempoolBlocks.$makeBlockTemplates(_memPool, true);
    } else {
      mempoolBlocks.updateMempoolBlocks(_memPool, true);
    }
@@ -496,6 +616,19 @@ class WebsocketHandler {
    const da = difficultyAdjustment.getDifficultyAdjustment();
    const fees = feeApi.getRecommendedFee();

+    // update init data
+    this.updateInitData();
+
+    const responseCache = { ...this.initData };
+    function getCachedResponse(key, data): string {
+      if (!responseCache[key]) {
+        responseCache[key] = JSON.stringify(data);
+      }
+      return responseCache[key];
+    }
+
+    const mempoolInfo = memPool.getMempoolInfo();
+
    this.wss.clients.forEach((client) => {
      if (client.readyState !== WebSocket.OPEN) {
        return;
@@ -505,19 +638,29 @@ class WebsocketHandler {
        return;
      }

-      const response = {
-        'block': block,
-        'mempoolInfo': memPool.getMempoolInfo(),
-        'da': da?.previousTime ? da : undefined,
-        'fees': fees,
-      };
+      const response = {};
+      response['block'] = getCachedResponse('block', block);
+      response['mempoolInfo'] = getCachedResponse('mempoolInfo', mempoolInfo);
+      response['da'] = getCachedResponse('da', da?.previousTime ? da : undefined);
+      response['fees'] = getCachedResponse('fees', fees);

      if (mBlocks && client['want-mempool-blocks']) {
-        response['mempool-blocks'] = mBlocks;
+        response['mempool-blocks'] = getCachedResponse('mempool-blocks', mBlocks);
      }

-      if (client['track-tx'] && txIds.indexOf(client['track-tx']) > -1) {
-        response['txConfirmed'] = true;
+      if (client['track-tx']) {
+        const trackTxid = client['track-tx'];
+        if (txIds.indexOf(trackTxid) > -1) {
+          response['txConfirmed'] = 'true';
+        } else {
+          const mempoolTx = _memPool[trackTxid];
+          if (mempoolTx && mempoolTx.position) {
+            response['txPosition'] = JSON.stringify({
+              txid: trackTxid,
+              position: mempoolTx.position,
+            });
+          }
+        }
      }

      if (client['track-address']) {
@@ -543,7 +686,7 @@ class WebsocketHandler {
            };
          });

-          response['block-transactions'] = foundTransactions;
+          response['block-transactions'] = JSON.stringify(foundTransactions);
        }
      }

@@ -580,23 +723,37 @@ class WebsocketHandler {
            };
          });

-          response['block-transactions'] = foundTransactions;
+          response['block-transactions'] = JSON.stringify(foundTransactions);
        }
      }

      if (client['track-mempool-block'] >= 0) {
        const index = client['track-mempool-block'];
        if (mBlockDeltas && mBlockDeltas[index]) {
-          response['projected-block-transactions'] = {
+          response['projected-block-transactions'] = getCachedResponse(`projected-block-transactions-${index}`, {
            index: index,
            delta: mBlockDeltas[index],
-          };
+          });
        }
      }

-      client.send(JSON.stringify(response));
+      const serializedResponse = '{'
+        + Object.keys(response).map(key => `"${key}": ${response[key]}`).join(', ')
+        + '}';
+      client.send(serializedResponse);
    });
  }
+
+  private printLogs(): void {
+    if (this.wss) {
+      const count = this.wss?.clients?.size || 0;
+      const diff = count - this.numClients;
+      this.numClients = count;
+      logger.debug(`${count} websocket clients | ${this.numConnected} connected | ${this.numDisconnected} disconnected | (${diff >= 0 ? '+' : ''}${diff})`);
+      this.numConnected = 0;
+      this.numDisconnected = 0;
+    }
+  }
 }

 export default new WebsocketHandler();
--- a/backend/src/config.ts
+++ b/backend/src/config.ts
@@ -37,6 +37,8 @@ interface IConfig {
  };
  ESPLORA: {
    REST_API_URL: string;
+    UNIX_SOCKET_PATH: string | void | null;
+    RETRY_UNIX_SOCKET_AFTER: number;
  };
  LIGHTNING: {
    ENABLED: boolean;
@@ -84,6 +86,7 @@ interface IConfig {
    DATABASE: string;
    USERNAME: string;
    PASSWORD: string;
+    TIMEOUT: number;
  };
  SYSLOG: {
    ENABLED: boolean;
@@ -163,6 +166,8 @@ const defaults: IConfig = {
  },
  'ESPLORA': {
    'REST_API_URL': 'http://127.0.0.1:3000',
+    'UNIX_SOCKET_PATH': null,
+    'RETRY_UNIX_SOCKET_AFTER': 30000,
  },
  'ELECTRUM': {
    'HOST': '127.0.0.1',
@@ -190,7 +195,8 @@ const defaults: IConfig = {
    'PORT': 3306,
    'DATABASE': 'mempool',
    'USERNAME': 'mempool',
-    'PASSWORD': 'mempool'
+    'PASSWORD': 'mempool',
+    'TIMEOUT': 180000,
  },
  'SYSLOG': {
    'ENABLED': true,
--- a/backend/src/database.ts
+++ b/backend/src/database.ts
@@ -33,8 +33,32 @@ import { FieldPacket, OkPacket, PoolOptions, ResultSetHeader, RowDataPacket } fr
    OkPacket[] | ResultSetHeader>(query, params?): Promise<[T, FieldPacket[]]>
  {
    this.checkDBFlag();
-    const pool = await this.getPool();
-    return pool.query(query, params);
+    let hardTimeout;
+    if (query?.timeout != null) {
+      hardTimeout = Math.floor(query.timeout * 1.1);
+    } else {
+      hardTimeout = config.DATABASE.TIMEOUT;
+    }
+    if (hardTimeout > 0) {
+      return new Promise((resolve, reject) => {
+        const timer = setTimeout(() => {
+          reject(new Error(`DB query failed to return, reject or time out within ${hardTimeout / 1000}s - ${query?.sql?.slice(0, 160) || (typeof(query) === 'string' || query instanceof String ? query?.slice(0, 160) : 'unknown query')}`));
+        }, hardTimeout);
+
+        this.getPool().then(pool => {
+          return pool.query(query, params) as Promise<[T, FieldPacket[]]>;
+        }).then(result => {
+          resolve(result);
+        }).catch(error => {
+          reject(error);
+        }).finally(() => {
+          clearTimeout(timer);
+        });
+      });
+    } else {
+      const pool = await this.getPool();
+      return pool.query(query, params);
+    }
  }

  public async checkDbConnection() {
--- a/backend/src/index.ts
+++ b/backend/src/index.ts
@@ -2,6 +2,7 @@ import express from 'express';
 import { Application, Request, Response, NextFunction } from 'express';
 import * as http from 'http';
 import * as WebSocket from 'ws';
+import bitcoinApi from './api/bitcoin/bitcoin-api-factory';
 import cluster from 'cluster';
 import DB from './database';
 import config from './config';
@@ -45,7 +46,8 @@ class Server {
  private wss: WebSocket.Server | undefined;
  private server: http.Server | undefined;
  private app: Application;
-  private currentBackendRetryInterval = 5;
+  private currentBackendRetryInterval = 1;
+  private backendRetryCount = 0;

  private maxHeapSize: number = 0;
  private heapLogInterval: number = 60;
@@ -120,7 +122,7 @@ class Server {
    await poolsUpdater.updatePoolsJson(); // Needs to be done before loading the disk cache because we sometimes wipe it
    await syncAssets.syncAssets$();
    if (config.MEMPOOL.ENABLED) {
-      diskCache.loadMempoolCache();
+      await diskCache.$loadMempoolCache();
    }

    if (config.STATISTICS.ENABLED && config.DATABASE.ENABLED && cluster.isPrimary) {
@@ -178,23 +180,26 @@ class Server {
          logger.debug(msg);
        }
      }
-      memPool.deleteExpiredTransactions();
-      await blocks.$updateBlocks();
-      await memPool.$updateMempool();
+      const newMempool = await bitcoinApi.$getRawMempool();
+      const numHandledBlocks = await blocks.$updateBlocks();
+      if (numHandledBlocks === 0) {
+        await memPool.$updateMempool(newMempool);
+      }
      indexer.$run();

-      setTimeout(this.runMainUpdateLoop.bind(this), config.MEMPOOL.POLL_RATE_MS);
-      this.currentBackendRetryInterval = 5;
+      // rerun immediately if we skipped the mempool update, otherwise wait POLL_RATE_MS
+      setTimeout(this.runMainUpdateLoop.bind(this), numHandledBlocks > 0 ? 1 : config.MEMPOOL.POLL_RATE_MS);
+      this.backendRetryCount = 0;
    } catch (e: any) {
-      let loggerMsg = `Exception in runMainUpdateLoop(). Retrying in ${this.currentBackendRetryInterval} sec.`;
+      this.backendRetryCount++;
+      let loggerMsg = `Exception in runMainUpdateLoop() (count: ${this.backendRetryCount}). Retrying in ${this.currentBackendRetryInterval} sec.`;
      loggerMsg += ` Reason: ${(e instanceof Error ? e.message : e)}.`;
      if (e?.stack) {
        loggerMsg += ` Stack trace: ${e.stack}`;
      }
      // When we get a first Exception, only `logger.debug` it and retry after 5 seconds
      // From the second Exception, `logger.warn` the Exception and increase the retry delay
-      // Maximum retry delay is 60 seconds
-      if (this.currentBackendRetryInterval > 5) {
+      if (this.backendRetryCount >= 5) {
        logger.warn(loggerMsg);
        mempool.setOutOfSync();
      } else {
@@ -204,8 +209,8 @@ class Server {
        logger.debug(`AxiosError: ${e?.message}`);
      }
      setTimeout(this.runMainUpdateLoop.bind(this), 1000 * this.currentBackendRetryInterval);
-      this.currentBackendRetryInterval *= 2;
-      this.currentBackendRetryInterval = Math.min(this.currentBackendRetryInterval, 60);
+    } finally {
+      diskCache.unlock();
    }
  }

@@ -238,7 +243,7 @@ class Server {
    websocketHandler.setupConnectionHandling();
    if (config.MEMPOOL.ENABLED) {
      statistics.setNewStatisticsEntryCallback(websocketHandler.handleNewStatistic.bind(websocketHandler));
-      memPool.setAsyncMempoolChangedCallback(websocketHandler.handleMempoolChange.bind(websocketHandler));
+      memPool.setAsyncMempoolChangedCallback(websocketHandler.$handleMempoolChange.bind(websocketHandler));
      blocks.setNewAsyncBlockCallback(websocketHandler.handleNewBlock.bind(websocketHandler));
    }
    priceUpdater.setRatesChangedCallback(websocketHandler.handleNewConversionRates.bind(websocketHandler));
@@ -276,7 +281,7 @@ class Server {

    if (!this.warnedHeapCritical && this.maxHeapSize > warnThreshold) {
      this.warnedHeapCritical = true;
-      logger.warn(`Used ${(this.maxHeapSize / stats.heap_size_limit).toFixed(2)}% of heap limit (${formatBytes(this.maxHeapSize, byteUnits, true)} / ${formatBytes(stats.heap_size_limit, byteUnits)})!`);
+      logger.warn(`Used ${(this.maxHeapSize / stats.heap_size_limit * 100).toFixed(2)}% of heap limit (${formatBytes(this.maxHeapSize, byteUnits, true)} / ${formatBytes(stats.heap_size_limit, byteUnits)})!`);
    }
    if (this.lastHeapLogTime === null || (now - this.lastHeapLogTime) > (this.heapLogInterval * 1000)) {
      logger.debug(`Memory usage: ${formatBytes(this.maxHeapSize, byteUnits)} / ${formatBytes(stats.heap_size_limit, byteUnits)}`);
--- a/backend/src/mempool.interfaces.ts
+++ b/backend/src/mempool.interfaces.ts
@@ -58,6 +58,7 @@ export interface MempoolBlockWithTransactions extends MempoolBlock {
 export interface MempoolBlockDelta {
  added: TransactionStripped[];
  removed: string[];
+  changed: { txid: string, rate: number | undefined }[];
 }

 interface VinStrippedToScriptsig {
@@ -79,18 +80,22 @@ export interface TransactionExtended extends IEsploraApi.Transaction {
  descendants?: Ancestor[];
  bestDescendant?: BestDescendant | null;
  cpfpChecked?: boolean;
-  deleteAfter?: number;
+  position?: {
+    block: number,
+    vsize: number,
+  };
+  uid?: number;
 }

 export interface AuditTransaction {
-  txid: string;
+  uid: number;
  fee: number;
  weight: number;
  feePerVsize: number;
  effectiveFeePerVsize: number;
-  vin: string[];
+  inputs: number[];
  relativesSet: boolean;
-  ancestorMap: Map<string, AuditTransaction>;
+  ancestorMap: Map<number, AuditTransaction>;
  children: Set<AuditTransaction>;
  ancestorFee: number;
  ancestorWeight: number;
@@ -100,13 +105,25 @@ export interface AuditTransaction {
  modifiedNode: HeapNode<AuditTransaction>;
 }

+export interface CompactThreadTransaction {
+  uid: number;
+  fee: number;
+  weight: number;
+  feePerVsize: number;
+  effectiveFeePerVsize?: number;
+  inputs: number[];
+  cpfpRoot?: string;
+  cpfpChecked?: boolean;
+  dirty?: boolean;
+}
+
 export interface ThreadTransaction {
  txid: string;
  fee: number;
  weight: number;
  feePerVsize: number;
  effectiveFeePerVsize?: number;
-  vin: string[];
+  inputs: number[];
  cpfpRoot?: string;
  cpfpChecked?: boolean;
 }
@@ -145,6 +162,7 @@ export interface TransactionStripped {
  fee: number;
  vsize: number;
  value: number;
+  rate?: number; // effective fee rate
 }

 export interface BlockExtension {
--- a/backend/src/repositories/BlocksRepository.ts
+++ b/backend/src/repositories/BlocksRepository.ts
@@ -13,6 +13,48 @@ import chainTips from '../api/chain-tips';
 import blocks from '../api/blocks';
 import BlocksAuditsRepository from './BlocksAuditsRepository';

+interface DatabaseBlock {
+  id: string;
+  height: number;
+  version: number;
+  timestamp: number;
+  bits: number;
+  nonce: number;
+  difficulty: number;
+  merkle_root: string;
+  tx_count: number;
+  size: number;
+  weight: number;
+  previousblockhash: string;
+  mediantime: number;
+  totalFees: number;
+  medianFee: number;
+  feeRange: string;
+  reward: number;
+  poolId: number;
+  poolName: string;
+  poolSlug: string;
+  avgFee: number;
+  avgFeeRate: number;
+  coinbaseRaw: string;
+  coinbaseAddress: string;
+  coinbaseSignature: string;
+  coinbaseSignatureAscii: string;
+  avgTxSize: number;
+  totalInputs: number;
+  totalOutputs: number;
+  totalOutputAmt: number;
+  medianFeeAmt: number;
+  feePercentiles: string;
+  segwitTotalTxs: number;
+  segwitTotalSize: number;
+  segwitTotalWeight: number;
+  header: string;
+  utxoSetChange: number;
+  utxoSetSize: number;
+  totalInputAmt: number;
+}
+
 const BLOCK_DB_FIELDS = `
  blocks.hash AS id,
  blocks.height,
@@ -52,7 +94,7 @@ const BLOCK_DB_FIELDS = `
  blocks.header,
  blocks.utxoset_change AS utxoSetChange,
  blocks.utxoset_size AS utxoSetSize,
-  blocks.total_input_amt AS totalInputAmts
+  blocks.total_input_amt AS totalInputAmt
 `;

 class BlocksRepository {
@@ -171,6 +213,32 @@ class BlocksRepository {
    }
  }

+  /**
+   * Update missing fee amounts fields
+   *
+   * @param blockHash 
+   * @param feeAmtPercentiles 
+   * @param medianFeeAmt 
+   */
+  public async $updateFeeAmounts(blockHash: string, feeAmtPercentiles, medianFeeAmt) : Promise<void> {
+    try {
+      const query = `
+        UPDATE blocks
+        SET fee_percentiles = ?, median_fee_amt = ?
+        WHERE hash = ?
+      `;
+      const params: any[] = [
+        JSON.stringify(feeAmtPercentiles),
+        medianFeeAmt,
+        blockHash
+      ];
+      await DB.query(query, params);
+    } catch (e: any) {
+      logger.err(`Cannot update fee amounts for block ${blockHash}. Reason: ' + ${e instanceof Error ? e.message : e}`);
+      throw e;
+    }
+  }
+
  /**
   * Get all block height that have not been indexed between [startHeight, endHeight]
   */
@@ -432,7 +500,7 @@ class BlocksRepository {

      const blocks: BlockExtended[] = [];
      for (const block of rows) {
-        blocks.push(await this.formatDbBlockIntoExtendedBlock(block));
+        blocks.push(await this.formatDbBlockIntoExtendedBlock(block as DatabaseBlock));
      }

      return blocks;
@@ -459,37 +527,13 @@ class BlocksRepository {
        return null;
      }

-      return await this.formatDbBlockIntoExtendedBlock(rows[0]);  
+      return await this.formatDbBlockIntoExtendedBlock(rows[0] as DatabaseBlock);  
    } catch (e) {
      logger.err(`Cannot get indexed block ${height}. Reason: ` + (e instanceof Error ? e.message : e));
      throw e;
    }
  }

-  /**
-   * Get one block by hash
-   */
-  public async $getBlockByHash(hash: string): Promise<object | null> {
-    try {
-      const query = `
-        SELECT ${BLOCK_DB_FIELDS}
-        FROM blocks
-        JOIN pools ON blocks.pool_id = pools.id
-        WHERE hash = ?;
-      `;
-      const [rows]: any[] = await DB.query(query, [hash]);
-
-      if (rows.length <= 0) {
-        return null;
-      }
- 
-      return await this.formatDbBlockIntoExtendedBlock(rows[0]);
-    } catch (e) {
-      logger.err(`Cannot get indexed block ${hash}. Reason: ` + (e instanceof Error ? e.message : e));
-      throw e;
-    }
-  }
-
  /**
   * Return blocks difficulty
   */
@@ -599,7 +643,6 @@ class BlocksRepository {
        if (blocks[idx].previous_block_hash !== blocks[idx - 1].hash) {
          logger.warn(`Chain divergence detected at block ${blocks[idx - 1].height}`);
          await this.$deleteBlocksFrom(blocks[idx - 1].height);
-          await BlocksSummariesRepository.$deleteBlocksFrom(blocks[idx - 1].height);
          await HashratesRepository.$deleteHashratesFromTimestamp(blocks[idx - 1].timestamp - 604800);
          await DifficultyAdjustmentsRepository.$deleteAdjustementsFromHeight(blocks[idx - 1].height);
          return false;
@@ -619,7 +662,7 @@ class BlocksRepository {
   * Delete blocks from the database from blockHeight
   */
  public async $deleteBlocksFrom(blockHeight: number) {
-    logger.info(`Delete newer blocks from height ${blockHeight} from the database`);
+    logger.info(`Delete newer blocks from height ${blockHeight} from the database`, logger.tags.mining);

    try {
      await DB.query(`DELETE FROM blocks where height >= ${blockHeight}`);
@@ -933,7 +976,7 @@ class BlocksRepository {
   * 
   * @param dbBlk 
   */
-  private async formatDbBlockIntoExtendedBlock(dbBlk: any): Promise<BlockExtended> {
+  private async formatDbBlockIntoExtendedBlock(dbBlk: DatabaseBlock): Promise<BlockExtended> {
    const blk: Partial<BlockExtended> = {};
    const extras: Partial<BlockExtension> = {};

@@ -997,6 +1040,7 @@ class BlocksRepository {
    }

    // If we're missing block summary related field, check if we can populate them on the fly now
+    // This is for example triggered upon re-org
    if (Common.blocksSummariesIndexingEnabled() &&
      (extras.medianFeeAmt === null || extras.feePercentiles === null))
    {
@@ -1004,11 +1048,12 @@ class BlocksRepository {
      if (extras.feePercentiles === null) {
        const block = await bitcoinClient.getBlock(dbBlk.id, 2);
        const summary = blocks.summarizeBlock(block);
-        await BlocksSummariesRepository.$saveSummary({ height: block.height, mined: summary });
+        await BlocksSummariesRepository.$saveTransactions(dbBlk.height, dbBlk.id, summary.transactions);
        extras.feePercentiles = await BlocksSummariesRepository.$getFeePercentilesByBlockId(dbBlk.id);
      }
      if (extras.feePercentiles !== null) {
        extras.medianFeeAmt = extras.feePercentiles[3];
+        await this.$updateFeeAmounts(dbBlk.id, extras.feePercentiles, extras.medianFeeAmt);
      }
    }

--- a/backend/src/repositories/BlocksSummariesRepository.ts
+++ b/backend/src/repositories/BlocksSummariesRepository.ts
@@ -1,6 +1,6 @@
 import DB from '../database';
 import logger from '../logger';
-import { BlockSummary } from '../mempool.interfaces';
+import { BlockSummary, TransactionStripped } from '../mempool.interfaces';

 class BlocksSummariesRepository {
  public async $getByBlockId(id: string): Promise<BlockSummary | undefined> {
@@ -17,23 +17,17 @@ class BlocksSummariesRepository {
    return undefined;
  }

-  public async $saveSummary(params: { height: number, mined?: BlockSummary}) {
-    const blockId = params.mined?.id;
+  public async $saveTransactions(blockHeight: number, blockId: string, transactions: TransactionStripped[]): Promise<void> {
    try {
-      const transactions = JSON.stringify(params.mined?.transactions || []);
+      const transactionsStr = JSON.stringify(transactions);
      await DB.query(`
-        INSERT INTO blocks_summaries (height, id, transactions, template)
-        VALUE (?, ?, ?, ?)
-        ON DUPLICATE KEY UPDATE
-          transactions = ?
-      `, [params.height, blockId, transactions, '[]', transactions]);
+        INSERT INTO blocks_summaries
+        SET height = ?, transactions = ?, id = ?
+        ON DUPLICATE KEY UPDATE transactions = ?`,
+        [blockHeight, transactionsStr, blockId, transactionsStr]);
    } catch (e: any) {
-      if (e.errno === 1062) { // ER_DUP_ENTRY - This scenario is possible upon node backend restart
-        logger.debug(`Cannot save block summary for ${blockId} because it has already been indexed, ignoring`);
-      } else {
-        logger.debug(`Cannot save block summary for ${blockId}. Reason: ${e instanceof Error ? e.message : e}`);
-        throw e;
-      }
+      logger.debug(`Cannot save block summary transactions for ${blockId}. Reason: ${e instanceof Error ? e.message : e}`);
+      throw e;
    }
  }

@@ -68,19 +62,6 @@ class BlocksSummariesRepository {
    return [];
  }

-  /**
-   * Delete blocks from the database from blockHeight
-   */
-  public async $deleteBlocksFrom(blockHeight: number) {
-    logger.info(`Delete newer blocks summary from height ${blockHeight} from the database`);
-
-    try {
-      await DB.query(`DELETE FROM blocks_summaries where height >= ${blockHeight}`);
-    } catch (e) {
-      logger.err('Cannot delete indexed blocks summaries. Reason: ' + (e instanceof Error ? e.message : e));
-    }
-  }
-
  /**
   * Get the fee percentiles if the block has already been indexed, [] otherwise
   * 
--- a/backend/src/repositories/HashratesRepository.ts
+++ b/backend/src/repositories/HashratesRepository.ts
@@ -220,7 +220,7 @@ class HashratesRepository {
   * Delete hashrates from the database from timestamp
   */
  public async $deleteHashratesFromTimestamp(timestamp: number) {
-    logger.info(`Delete newer hashrates from timestamp ${new Date(timestamp * 1000).toUTCString()} from the database`);
+    logger.info(`Delete newer hashrates from timestamp ${new Date(timestamp * 1000).toUTCString()} from the database`, logger.tags.mining);

    try {
      await DB.query(`DELETE FROM hashrates WHERE hashrate_timestamp >= FROM_UNIXTIME(?)`, [timestamp]);
--- a/backend/src/repositories/PricesRepository.ts
+++ b/backend/src/repositories/PricesRepository.ts
@@ -160,7 +160,7 @@ class PricesRepository {

      // Compute fiat exchange rates
      let latestPrice = rates[0] as ApiPrice;
-      if (latestPrice.USD === -1) {
+      if (!latestPrice || latestPrice.USD === -1) {
        latestPrice = priceUpdater.getEmptyPricesObj();
      }

--- a/backend/src/tasks/lightning/forensics.service.ts
+++ b/backend/src/tasks/lightning/forensics.service.ts
@@ -27,7 +27,7 @@ class ForensicsService {

  private async $runTasks(): Promise<void> {
    try {
-      logger.info(`Running forensics scans`);
+      logger.debug(`Running forensics scans`);

      if (config.MEMPOOL.BACKEND === 'esplora') {
        await this.$runClosedChannelsForensics(false);
@@ -73,7 +73,7 @@ class ForensicsService {
    let progress = 0;

    try {
-      logger.info(`Started running closed channel forensics...`);
+      logger.debug(`Started running closed channel forensics...`);
      let channels;
      if (onlyNewChannels) {
        channels = await channelsApi.$getClosedChannelsWithoutReason();
@@ -152,11 +152,11 @@ class ForensicsService {
        ++progress;
        const elapsedSeconds = Math.round((new Date().getTime() / 1000) - this.loggerTimer);
        if (elapsedSeconds > 10) {
-          logger.info(`Updating channel closed channel forensics ${progress}/${channels.length}`);
+          logger.debug(`Updating channel closed channel forensics ${progress}/${channels.length}`);
          this.loggerTimer = new Date().getTime() / 1000;
        }
      }
-      logger.info(`Closed channels forensics scan complete.`);
+      logger.debug(`Closed channels forensics scan complete.`);
    } catch (e) {
      logger.err('$runClosedChannelsForensics() error: ' + (e instanceof Error ? e.message : e));
    }
@@ -217,7 +217,7 @@ class ForensicsService {
    let progress = 0;

    try {
-      logger.info(`Started running open channel forensics...`);
+      logger.debug(`Started running open channel forensics...`);
      const channels = await channelsApi.$getChannelsWithoutSourceChecked();

      for (const openChannel of channels) {
@@ -257,7 +257,7 @@ class ForensicsService {
        ++progress;
        const elapsedSeconds = Math.round((new Date().getTime() / 1000) - this.loggerTimer);
        if (elapsedSeconds > 10) {
-          logger.info(`Updating opened channel forensics ${progress}/${channels?.length}`);
+          logger.debug(`Updating opened channel forensics ${progress}/${channels?.length}`);
          this.loggerTimer = new Date().getTime() / 1000;
          this.truncateTempCache();
        }
@@ -266,7 +266,7 @@ class ForensicsService {
        }
      }

-      logger.info(`Open channels forensics scan complete.`);
+      logger.debug(`Open channels forensics scan complete.`);
    } catch (e) {
      logger.err('$runOpenedChannelsForensics() error: ' + (e instanceof Error ? e.message : e));
    } finally {
--- a/backend/src/tasks/lightning/network-sync.service.ts
+++ b/backend/src/tasks/lightning/network-sync.service.ts
@@ -287,7 +287,7 @@ class NetworkSyncService {
      } else {
        log += ` for the first time`;
      }
-      logger.info(`${log}`, logger.tags.ln);
+      logger.debug(`${log}`, logger.tags.ln);

      const channels = await channelsApi.$getChannelsByStatus([0, 1]);
      for (const channel of channels) {
@@ -304,7 +304,7 @@ class NetworkSyncService {
        ++progress;
        const elapsedSeconds = Math.round((new Date().getTime() / 1000) - this.loggerTimer);
        if (elapsedSeconds > config.LIGHTNING.LOGGER_UPDATE_INTERVAL) {
-          logger.info(`Checking if channel has been closed ${progress}/${channels.length}`, logger.tags.ln);
+          logger.debug(`Checking if channel has been closed ${progress}/${channels.length}`, logger.tags.ln);
          this.loggerTimer = new Date().getTime() / 1000;
        }
      }
--- a/backend/src/tasks/lightning/sync-tasks/stats-importer.ts
+++ b/backend/src/tasks/lightning/sync-tasks/stats-importer.ts
@@ -15,16 +15,20 @@ class LightningStatsImporter {
  topologiesFolder = config.LIGHTNING.TOPOLOGY_FOLDER;

  async $run(): Promise<void> {
-    const [channels]: any[] = await DB.query('SELECT short_id from channels;');
-    logger.info(`Caching funding txs for currently existing channels`, logger.tags.ln);
-    await fundingTxFetcher.$fetchChannelsFundingTxs(channels.map(channel => channel.short_id));
+    try {
+      const [channels]: any[] = await DB.query('SELECT short_id from channels;');
+      logger.info(`Caching funding txs for currently existing channels`, logger.tags.ln);
+      await fundingTxFetcher.$fetchChannelsFundingTxs(channels.map(channel => channel.short_id));

-    if (config.MEMPOOL.NETWORK !== 'mainnet' || config.DATABASE.ENABLED === false) {
-      return;
+      if (config.MEMPOOL.NETWORK !== 'mainnet' || config.DATABASE.ENABLED === false) {
+        return;
+      }
+
+      await this.$importHistoricalLightningStats();
+      await this.$cleanupIncorrectSnapshot();
+    } catch (e) {
+      logger.err(`Exception in LightningStatsImporter::$run(). ${e}`);
    }
-
-    await this.$importHistoricalLightningStats();
-    await this.$cleanupIncorrectSnapshot();
  }

  /**
--- a/backend/src/tasks/pools-updater.ts
+++ b/backend/src/tasks/pools-updater.ts
@@ -62,7 +62,7 @@ class PoolsUpdater {
      if (this.currentSha === null) {
        logger.info(`Downloading pools-v2.json for the first time from ${this.poolsUrl} over ${network}`, logger.tags.mining);
      } else {
-        logger.warn(`pools-v2.json is outdated, fetch latest from ${this.poolsUrl} over ${network}`, logger.tags.mining);
+        logger.warn(`pools-v2.json is outdated, fetching latest from ${this.poolsUrl} over ${network}`, logger.tags.mining);
      }
      const poolsJson = await this.query(this.poolsUrl);
      if (poolsJson === undefined) {
--- a/backend/src/tasks/price-updater.ts
+++ b/backend/src/tasks/price-updater.ts
@@ -222,7 +222,7 @@ class PriceUpdater {
  private async $insertMissingRecentPrices(type: 'hour' | 'day'): Promise<void> {
    const existingPriceTimes = await PricesRepository.$getPricesTimes();

-    logger.info(`Fetching ${type === 'day' ? 'dai' : 'hour'}ly price history from exchanges and saving missing ones into the database`, logger.tags.mining);
+    logger.debug(`Fetching ${type === 'day' ? 'dai' : 'hour'}ly price history from exchanges and saving missing ones into the database`, logger.tags.mining);

    const historicalPrices: PriceHistory[] = [];