rpc: reserve space for UniValue variables in blockToJSON

- Reserving space avoid reallocation, this provide noticeable performance increase in verbosity level 1, 2.
ismaelsadeeq · Oct 30, 2024 · f8d5d2c · f8d5d2c
1 parent 952463c
commit f8d5d2c
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diff --git a/src/core_write.cpp b/src/core_write.cpp
@@ -181,6 +181,7 @@ void TxToUniv(const CTransaction& tx, const uint256& block_hash, UniValue& entry
     entry.pushKV("locktime", (int64_t)tx.nLockTime);
 
     UniValue vin{UniValue::VARR};
+    vin.reserve(tx.vin.size());
 
     // If available, use Undo data to calculate the fee. Note that txundo == nullptr
     // for coinbase transactions and for transactions where undo data is unavailable.
@@ -232,6 +233,7 @@ void TxToUniv(const CTransaction& tx, const uint256& block_hash, UniValue& entry
     entry.pushKV("vin", std::move(vin));
 
     UniValue vout(UniValue::VARR);
+    vout.reserve(tx.vout.size());
     for (unsigned int i = 0; i < tx.vout.size(); i++) {
         const CTxOut& txout = tx.vout[i];
 

diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
@@ -181,6 +181,7 @@ UniValue blockToJSON(BlockManager& blockman, const CBlock& block, const CBlockIn
     result.pushKV("size", (int)::GetSerializeSize(TX_WITH_WITNESS(block)));
     result.pushKV("weight", (int)::GetBlockWeight(block));
     UniValue txs(UniValue::VARR);
+    txs.reserve(block.vtx.size());
 
     switch (verbosity) {
         case TxVerbosity::SHOW_TXID: