Reduce the network size of mempool block websocket updates

backend/src/api/mempool-blocks.ts

@@ -1,6 +1,6 @@
 import { GbtGenerator, GbtResult, ThreadTransaction as RustThreadTransaction, ThreadAcceleration as RustThreadAcceleration } from 'rust-gbt';
 import logger from '../logger';
-import { MempoolBlock, MempoolTransactionExtended, MempoolBlockWithTransactions, MempoolBlockDelta, Ancestor, CompactThreadTransaction, EffectiveFeeStats, PoolTag, TransactionClassified } from '../mempool.interfaces';
+import { MempoolBlock, MempoolTransactionExtended, MempoolBlockWithTransactions, MempoolBlockDelta, Ancestor, CompactThreadTransaction, EffectiveFeeStats, PoolTag, TransactionClassified, TransactionCompressed, MempoolDeltaChange } from '../mempool.interfaces';
 import { Common, OnlineFeeStatsCalculator } from './common';
 import config from '../config';
 import { Worker } from 'worker_threads';
@@ -171,7 +171,7 @@ class MempoolBlocks {
     for (let i = 0; i < Math.max(mempoolBlocks.length, prevBlocks.length); i++) {
       let added: TransactionClassified[] = [];
       let removed: string[] = [];
-      const changed: { txid: string, rate: number | undefined, acc: boolean | undefined }[] = [];
+      const changed: TransactionClassified[] = [];
       if (mempoolBlocks[i] && !prevBlocks[i]) {
         added = mempoolBlocks[i].transactions;
       } else if (!mempoolBlocks[i] && prevBlocks[i]) {
@@ -194,14 +194,14 @@ class MempoolBlocks {
           if (!prevIds[tx.txid]) {
             added.push(tx);
           } else if (tx.rate !== prevIds[tx.txid].rate || tx.acc !== prevIds[tx.txid].acc) {
-            changed.push({ txid: tx.txid, rate: tx.rate, acc: tx.acc });
+            changed.push(tx);
           }
         });
       }
       mempoolBlockDeltas.push({
-        added,
+        added: added.map(this.compressTx),
         removed,
-        changed,
+        changed: changed.map(this.compressDeltaChange),
       });
     }
     return mempoolBlockDeltas;
@@ -691,6 +691,38 @@ class MempoolBlocks {
     });
     return { blocks: convertedBlocks, blockWeights, rates: convertedRates, clusters: convertedClusters, overflow: convertedOverflow };
   }
+
+  public compressTx(tx: TransactionClassified): TransactionCompressed {
+    if (tx.acc) {
+      return [
+        tx.txid,
+        tx.fee,
+        tx.vsize,
+        tx.value,
+        Math.round((tx.rate || (tx.fee / tx.vsize)) * 100) / 100,
+        tx.flags,
+        1
+      ];
+    } else {
+      return [
+        tx.txid,
+        tx.fee,
+        tx.vsize,
+        tx.value,
+        Math.round((tx.rate || (tx.fee / tx.vsize)) * 100) / 100,
+        tx.flags,
+      ];
+    }
+  }
+
+  public compressDeltaChange(tx: TransactionClassified): MempoolDeltaChange {
+    return [
+      tx.txid,
+      Math.round((tx.rate || (tx.fee / tx.vsize)) * 100) / 100,
+      tx.flags,
+      tx.acc ? 1 : 0,
+    ];
+  }
 }
 
 export default new MempoolBlocks();

backend/src/api/websocket-handler.ts

@@ -259,7 +259,7 @@ class WebsocketHandler {
               const mBlocksWithTransactions = mempoolBlocks.getMempoolBlocksWithTransactions();
               response['projected-block-transactions'] = JSON.stringify({
                 index: index,
-                blockTransactions: mBlocksWithTransactions[index]?.transactions || [],
+                blockTransactions: (mBlocksWithTransactions[index]?.transactions || []).map(mempoolBlocks.compressTx),
               });
             } else {
               client['track-mempool-block'] = null;
@@ -999,7 +999,7 @@ class WebsocketHandler {
           if (mBlockDeltas[index].added.length > (mBlocksWithTransactions[index]?.transactions.length / 2)) {
             response['projected-block-transactions'] = getCachedResponse(`projected-block-transactions-full-${index}`, {
               index: index,
-              blockTransactions: mBlocksWithTransactions[index].transactions,
+              blockTransactions: mBlocksWithTransactions[index].transactions.map(mempoolBlocks.compressTx),
             });
           } else {
             response['projected-block-transactions'] = getCachedResponse(`projected-block-transactions-delta-${index}`, {

backend/src/mempool.interfaces.ts

@@ -65,9 +65,9 @@ export interface MempoolBlockWithTransactions extends MempoolBlock {
 }
 
 export interface MempoolBlockDelta {
-  added: TransactionClassified[];
+  added: TransactionCompressed[];
   removed: string[];
-  changed: { txid: string, rate: number | undefined, flags?: number }[];
+  changed: MempoolDeltaChange[];
 }
 
 interface VinStrippedToScriptsig {
@@ -196,6 +196,11 @@ export interface TransactionClassified extends TransactionStripped {
   flags: number;
 }
 
+// [txid, fee, vsize, value, rate, flags, acceleration?]
+export type TransactionCompressed = [string, number, number, number, number, number, 1?];
+// [txid, rate, flags, acceleration?]
+export type MempoolDeltaChange = [string, number, number, (1|0)];
+
 // binary flags for transaction classification
 export const TransactionFlags = {
   // features