Skip the mempool backlog on startup for large (mainnet) mempools

First mempool pass over a >200-tx mempool would fire thousands of getrawtransaction
calls at the node in a burst. Mark the existing backlog seen and scan only new
arrivals instead; small (regtest) mempools still scan fully.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

1 files changed, 8 insertions, 0 deletions

diff --git a/tools/sp-indexer.js b/tools/sp-indexer.js
index 934c55c..5611bb5 100644
--- a/tools/sp-indexer.js
+++ b/tools/sp-indexer.js
@@ -169,10 +169,18 @@ async function scanMempoolTx(txid) {
   return { txid: tx.txid, tweak: Buffer.from(tweak).toString('hex'), outputs };
 }
 
+let mempoolInit = false;
 async function mempoolSync() {
   try {
     const txids = await rpc('getrawmempool', []);
     const inPool = new Set(txids);
+    if (!mempoolInit) {
+      mempoolInit = true;
+      // Don't scan a large (mainnet) backlog on startup — that's thousands of
+      // getrawtransaction calls in a burst on the node. Mark it seen and watch
+      // only new arrivals. A small (regtest) mempool is cheap, so scan it.
+      if (txids.length > 200) { for (const txid of txids) mempoolSeen.set(txid, null); return; }
+    }
     let changed = false;
     for (const txid of txids) {
       if (mempoolSeen.has(txid)) continue;