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0ac969cddfdba52f7947e9b140ef36e2b19c2c41 validation: don't reallocate cache for short-lived CCoinsViewCache (Lőrinc) c8f5e446dc95712a63e4dd88786e2f7cb697b986 coins: reduce lookups in dbcache layer propagation (Lőrinc) Pull request description: This change is part of [[IBD] - Tracking PR for speeding up Initial Block Download](https://github.com/bitcoin/bitcoin/pull/32043) ### Summary Previously, when the parent coins cache had no entry and the child did, `BatchWrite` performed a find followed by `try_emplace`, which resulted in multiple `SipHash` computations and bucket traversals on the common insert path. On a different path, these caches were recreated needlessly for every block connection. ### Fix for double fetch This change uses a single leading `try_emplace` and branches on the returned `inserted` flag. In the `FRESH && SPENT` case (not used in production, only exercised by tests), we erase the just-inserted placeholder (which is constant time with no rehash anyway). Semantics are unchanged for all valid parent/child state combinations. This change is a minimal version of [bitcoin/bitcoin@`723c49b` (#32128)](723c49b63b) and draws simplification ideas [bitcoin/bitcoin@`ae76ec7` (#30673)](ae76ec7bcf) and https://github.com/bitcoin/bitcoin/pull/30326. ### Fix for temporary cache recreation Related to parent cache propagation, the second commit makes it possible to avoid destructuring-recreating-destructuring of these short-live parent caches created for each new block. A few temporary `CCoinsViewCache`'s are destructed right after the `Flush()`, therefore it is not necessary to call `ReallocateCache` to recreate them right before they're killed anyway. This change was based on a subset of https://github.com/bitcoin/bitcoin/pull/28945, the original authors and relevant commenters were added as coauthors to this version. ----- Reindex-chainstate indicates ~1% speedup. <details> <summary>Details</summary> ```python COMMITS="647cdb4f7e8041affed887e2325ee03a91078bb1 0b0c3293ffd75afb27dadc0b28426b40132a8c6b"; \ STOP=909090; DBCACHE=4500; \ CC=gcc; CXX=g++; \ BASE_DIR="/mnt/my_storage"; DATA_DIR="$BASE_DIR/BitcoinData"; LOG_DIR="$BASE_DIR/logs"; \ (echo ""; for c in $COMMITS; do git fetch -q origin $c && git log -1 --pretty='%h %s' $c || exit 1; done; echo "") && \ hyperfine \ --sort command \ --runs 2 \ --export-json "$BASE_DIR/rdx-$(sed -E 's/(\w{8})\w+ ?/\1-/g;s/-$//'<<<"$COMMITS")-$STOP-$DBCACHE-$CC.json" \ --parameter-list COMMIT ${COMMITS// /,} \ --prepare "killall bitcoind 2>/dev/null; rm -f $DATA_DIR/debug.log; git checkout {COMMIT}; git clean -fxd; git reset --hard && \ cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Release -DENABLE_IPC=OFF && ninja -C build bitcoind && \ ./build/bin/bitcoind -datadir=$DATA_DIR -stopatheight=$STOP -dbcache=1000 -printtoconsole=0; sleep 20" \ --cleanup "cp $DATA_DIR/debug.log $LOG_DIR/debug-{COMMIT}-$(date +%s).log" \ "COMPILER=$CC ./build/bin/bitcoind -datadir=$DATA_DIR -stopatheight=$STOP -dbcache=$DBCACHE -reindex-chainstate -blocksonly -connect=0 -printtoconsole=0" 647cdb4f7e Merge bitcoin/bitcoin#33311: net: Quiet down logging when router doesn't support natpmp/pcp 0b0c3293ff validation: don't reallocate cache for short-lived CCoinsViewCache Benchmark 1: COMPILER=gcc ./build/bin/bitcoind -datadir=/mnt/my_storage/BitcoinData -stopatheight=909090 -dbcache=4500 -reindex-chainstate -blocksonly -connect=0 -printtoconsole=0 (COMMIT = 647cdb4f7e8041affed887e2325ee03a91078bb1) Time (mean ± σ): 16233.508 s ± 9.501 s [User: 19064.578 s, System: 951.672 s] Range (min … max): 16226.790 s … 16240.226 s 2 runs Benchmark 2: COMPILER=gcc ./build/bin/bitcoind -datadir=/mnt/my_storage/BitcoinData -stopatheight=909090 -dbcache=4500 -reindex-chainstate -blocksonly -connect=0 -printtoconsole=0 (COMMIT = 0b0c3293ffd75afb27dadc0b28426b40132a8c6b) Time (mean ± σ): 16039.626 s ± 17.284 s [User: 18870.130 s, System: 950.722 s] Range (min … max): 16027.405 s … 16051.848 s 2 runs Relative speed comparison 1.01 ± 0.00 COMPILER=gcc ./build/bin/bitcoind -datadir=/mnt/my_storage/BitcoinData -stopatheight=909090 -dbcache=4500 -reindex-chainstate -blocksonly -connect=0 -printtoconsole=0 (COMMIT = 647cdb4f7e8041affed887e2325ee03a91078bb1) 1.00 COMPILER=gcc ./build/bin/bitcoind -datadir=/mnt/my_storage/BitcoinData -stopatheight=909090 -dbcache=4500 -reindex-chainstate -blocksonly -connect=0 -printtoconsole=0 (COMMIT = 0b0c3293ffd75afb27dadc0b28426b40132a8c6b) ``` </details> ACKs for top commit: optout21: utACK 0ac969cddfdba52f7947e9b140ef36e2b19c2c41 achow101: ACK 0ac969cddfdba52f7947e9b140ef36e2b19c2c41 andrewtoth: utACK 0ac969cddfdba52f7947e9b140ef36e2b19c2c41 sedited: ACK 0ac969cddfdba52f7947e9b140ef36e2b19c2c41 Tree-SHA512: 9fcc3f1a8314368576a4fba96ca72665527eaa3a97964ab5b39491757f3527147d134f79a5c3456f76c1330c7ef862989d23f764236c5e2563be89a81c1cee47