a145fa881a
032223f403dbwrapper: reuse iterator scratch stream (Lőrinc)7403c0f907dbwrapper: guard `CDBBatch` scratch streams (Lőrinc)cb1ab0a716test: cover repeated dbwrapper stream use (Lőrinc)31ce729b28streams: add `ScopedDataStreamUsage` (Lőrinc) Pull request description: ### Problem `CDBIterator::GetValue()` cannot use `SpanReader` the same way as `::GetKey()` because values are deobfuscated in place before deserialization, so it still needs an owning mutable buffer. However, the current path allocates a fresh `DataStream` for every value read. The same local-stream pattern also exists in `CDBIterator::Seek()`, while `CDBBatch` already owns reusable key/value buffers but still manually reserves and clears them on every `Write()` and `Erase()` call. ### Fix Add `ScopedDataStreamUsage`, a small RAII helper for caller-owned scratch streams. It asserts that the stream is empty on entry (making accidental re-entry or concurrent use of the same scratch stream fail fast), and clears it on scope exit. Use it to guard the reusable scratch streams in `CDBBatch::Write()`, `::Erase()` and `CDBIterator::Seek()`, `::GetValue()`. The const read-side `CDBWrapper` helpers stay unchanged, since they can be called concurrently on the same wrapper and should keep using local streams. The production changes are preceded by tests covering repeated reuse on the same owning objects, including a failed iterator value decode followed by a successful read from the same iterator entry. ### Context Follow-up to #35128, #34483 and #35025. ### Reproducer `gettxoutsetinfo` gets an additional ~6% speedup on top of the previous iterator-key optimization: <details><summary>2026-04-24 | gettxoutsetinfo | i9-ssd | x86_64 | Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz | 16 cores | 62Gi RAM | xfs | SSD</summary> ```bash COMMITS="2d5ab09f0dca4bfec0b365f5f431def2c0c9d70f 9e5fd595ae8ebeec74678c31a547fbc14f87bf89"; \ BASE_DIR="/mnt/my_storage"; DATA_DIR="$BASE_DIR/BitcoinData"; LOG_DIR="$BASE_DIR/logs"; \ mkdir -p "$LOG_DIR" && \ (echo ""; for c in $COMMITS; do git cat-file -e "$c^{commit}" 2>/dev/null || git fetch -q origin "$c" || exit 1; git log -1 --pretty='%h %s' "$c" || exit 1; done) && \ (echo "" && echo "$(date -I) | gettxoutsetinfo | $(hostname) | $(uname -m) | $(lscpu | grep 'Model name' | head -1 | cut -d: -f2 | xargs) | $(nproc) cores | $(free -h | awk '/^Mem:/{print $2}') RAM | $(df -T $BASE_DIR | awk 'NR==2{print $2}') | $(lsblk -no ROTA $(df --output=source $BASE_DIR | tail -1) | grep -q 1 && echo HDD || echo SSD)"; echo "") && \ hyperfine \ --sort command \ --runs 3 \ --export-json "$BASE_DIR/gettxoutsetinfo-$(sed -E 's/([a-f0-9]{8})[a-f0-9]* ?/\1-/g;s/-$//'<<<"$COMMITS")-$(date +%s).json" \ --parameter-list COMMIT ${COMMITS// /,} \ --prepare "killall -9 bitcoind 2>/dev/null || true; rm -f $DATA_DIR/debug.log; git clean -fxd && git reset --hard {COMMIT} && \ cmake -B build -G Ninja -DCMAKE_BUILD_TYPE=Release && ninja -C build bitcoind bitcoin-cli -j$(nproc) && \ ./build/bin/bitcoind -datadir=$DATA_DIR -connect=0 -listen=0 -dnsseed=0 -coinstatsindex=0 -txindex=0 -blockfilterindex=0 -daemon -printtoconsole=0; \ ./build/bin/bitcoin-cli -datadir=$DATA_DIR -rpcwait getblockcount >/dev/null" \ --conclude "./build/bin/bitcoin-cli -datadir=$DATA_DIR stop 2>/dev/null || true; killall bitcoind 2>/dev/null || true; sleep 10; \ grep -q 'Done loading' $DATA_DIR/debug.log && grep 'Bitcoin Core version' $DATA_DIR/debug.log | grep -q \"\$(git rev-parse --short=12 {COMMIT})\"; \ cp $DATA_DIR/debug.log $LOG_DIR/gettxoutsetinfo-{COMMIT}-$(date +%s).log" \ "./build/bin/bitcoin-cli -datadir=$DATA_DIR -rpcclienttimeout=0 -named gettxoutsetinfo hash_type='none' use_index='false' >/dev/null"2d5ab09f0dMerge bitcoin/bitcoin#35124: bench: fix benchmark fixtures and setup checks cb63e158d9 walletdb: reuse batch scratch streams 2026-04-24 | gettxoutsetinfo | i9-ssd | x86_64 | Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz | 16 cores | 62Gi RAM | xfs | SSD Benchmark 1: ./build/bin/bitcoin-cli -datadir=/mnt/my_storage/BitcoinData -rpcclienttimeout=0 -named gettxoutsetinfo hash_type='none' use_index='false' >/dev/null (COMMIT =2d5ab09f0d) Time (mean ± σ): 60.063 s ± 1.623 s [User: 0.001 s, System: 0.002 s] Range (min … max): 59.020 s … 61.933 s 3 runs Benchmark 2: ./build/bin/bitcoin-cli -datadir=/mnt/my_storage/BitcoinData -rpcclienttimeout=0 -named gettxoutsetinfo hash_type='none' use_index='false' >/dev/null (COMMIT = cb63e158d9ae8276dbe54bba0b0cf8f35378ec71) Time (mean ± σ): 56.853 s ± 0.179 s [User: 0.002 s, System: 0.001 s] Range (min … max): 56.675 s … 57.033 s 3 runs Relative speed comparison 1.06 ± 0.03 ./build/bin/bitcoin-cli -datadir=/mnt/my_storage/BitcoinData -rpcclienttimeout=0 -named gettxoutsetinfo hash_type='none' use_index='false' >/dev/null (COMMIT =2d5ab09f0d) 1.00 ./build/bin/bitcoin-cli -datadir=/mnt/my_storage/BitcoinData -rpcclienttimeout=0 -named gettxoutsetinfo hash_type='none' use_index='false' >/dev/null (COMMIT = cb63e158d9ae8276dbe54bba0b0cf8f35378ec71) ``` </details> ACKs for top commit: andrewtoth: re-ACK032223f403CruzMolina: tACK032223f403achow101: ACK032223f403optout21: ACK032223f403sedited: ACK032223f403Tree-SHA512: 6ed51d1a492ca216108b10c01668b01f986260641714951da1d282f1dacf87f0df2b312108f24c06151d3b81eaa4ca6eb4e9ab4e2d829346b0e8f07d0c569a1e
Bitcoin Core integration/staging tree
For an immediately usable, binary version of the Bitcoin Core software, see https://bitcoincore.org/en/download/.
What is Bitcoin Core?
Bitcoin Core connects to the Bitcoin peer-to-peer network to download and fully validate blocks and transactions. It also includes a wallet and graphical user interface, which can be optionally built.
Further information about Bitcoin Core is available in the doc folder.
License
Bitcoin Core is released under the terms of the MIT license. See COPYING for more information or see https://opensource.org/license/MIT.
Development Process
The master branch is regularly built (see doc/build-*.md for instructions) and tested, but it is not guaranteed to be
completely stable. Tags are created
regularly from release branches to indicate new official, stable release versions of Bitcoin Core.
The https://github.com/bitcoin-core/gui repository is used exclusively for the development of the GUI. Its master branch is identical in all monotree repositories. Release branches and tags do not exist, so please do not fork that repository unless it is for development reasons.
The contribution workflow is described in CONTRIBUTING.md and useful hints for developers can be found in doc/developer-notes.md.
Testing
Testing and code review is the bottleneck for development; we get more pull requests than we can review and test on short notice. Please be patient and help out by testing other people's pull requests, and remember this is a security-critical project where any mistake might cost people lots of money.
Automated Testing
Developers are strongly encouraged to write unit tests for new code, and to
submit new unit tests for old code. Unit tests can be compiled and run
(assuming they weren't disabled during the generation of the build system) with: ctest. Further details on running
and extending unit tests can be found in /src/test/README.md.
There are also regression and integration tests, written
in Python.
These tests can be run (if the test dependencies are installed) with: build/test/functional/test_runner.py
(assuming build is your build directory).
The CI (Continuous Integration) systems make sure that every pull request is tested on Windows, Linux, and macOS. The CI must pass on all commits before merge to avoid unrelated CI failures on new pull requests.
Manual Quality Assurance (QA) Testing
Changes should be tested by somebody other than the developer who wrote the code. This is especially important for large or high-risk changes. It is useful to add a test plan to the pull request description if testing the changes is not straightforward.
Translations
Changes to translations as well as new translations can be submitted to Bitcoin Core's Transifex page.
Translations are periodically pulled from Transifex and merged into the git repository. See the translation process for details on how this works.
Important: We do not accept translation changes as GitHub pull requests because the next pull from Transifex would automatically overwrite them again.