Berkeley DB (libdb)

Not affiliated with or endorsed by Oracle Corporation. "Berkeley DB" is used here to name the software this project archives and forks. Releases v5.3.29 and later are community fork releases and are not Oracle artifacts (Oracle's final 5.3 release was 5.3.28).

This repository is two things at once:

1. A historical archive of Berkeley DB — the complete published lineage of releases and official patches that could be recovered, preserved as tags and GitHub Releases for reference and git diff-able history.
2. A living fork under active development on the master branch, where new work (bug fixes, portability, performance, and new features) happens.

Berkeley DB is an embedded, transactional key/value storage engine (B-tree, Hash, Queue, Recno) with ACID transactions, fine-grained locking, write-ahead logging, MVCC snapshot isolation, and replication. It is a library you link into your application — no server process.

Branches and tags

Ref	What it is
master	The living fork. Active development; the place to base PRs.
historical	A linear, chronological reconstruction of Berkeley DB 1.85 (1992) → 5.1.29 (2011). Archival; never rebased.
vX.Y.Z tags	Each upstream release, imported verbatim (with its upstream .tar.gz attached to the GitHub Release).
vX.Y.Z.N tags	Each official upstream patch, applied as its own commit.
vX.Y.Z-NC tags	"No-Crypto" export variants, branched from their base release.
v4.6.21-SSI	Michael Cahill's SIGMOD-2008 Serializable Snapshot Isolation research prototype, reproduced verbatim on 4.6.21.
v5.3.21/28, v5.3.29	The maintained 5.3.x line that master builds on.

Browsing the archive

git tag -l | sort -V                 # every archived version
git log --oneline --reverse historical
git diff v4.5.20 v4.6.21             # what changed between releases
git diff v4.6.21 v4.6.21.2           # what a single official patch changed
git diff v4.2.52 v4.2.52-NC          # what the no-crypto variant strips

See the historical branch README for full provenance and the per-version index.

What's new on the living fork

• Serializable Snapshot Isolation (SSI) — the DB_TXN_SNAPSHOT transaction mode is now serializable: it detects dangerous read/write dependency structures and aborts the pivot with DB_SNAPSHOT_CONFLICT. Both of Cahill's rw-conflict detection mechanisms are implemented: the lock-table path (a concurrent writer meeting a reader's SIREAD marker) and the MVCC version-chain path in mp_fget (a reader handed an older version than one a concurrent writer committed). SIREAD markers are reclaimed incrementally and bounded (not only at checkpoint); the commit-time pivot check is race-free against concurrent edge recording; and a DB_TXN_SNAPSHOT transaction is rejected with prepare()/2PC. (This fork makes DB_TXN_SNAPSHOT serializable and removed the earlier separate DB_TXN_SNAPSHOT_SAFE flag — a deliberate ABI break.) The SIREAD marker/locker/detail lifetime is hardened for concurrent writers: a family of pre-existing use-after-free bugs (most importantly a lock object reclaimed while it still held SIREAD markers) was found with TSan/ASan and fixed, and a multi-process concurrent-writer stress test (ssi009) guards against regression. Still experimental in that page-granularity conflict tracking can raise abort rates under contention (measured by the microbenchmark suite under test/bench), and the HA/replication qualification is still being built. Planned performance work is tracked as design proposals under rfc/, targeting matching or beating InnoDB and WiredTiger on multicore/NUMA scalability and performance.

Building

Two build systems produce the core library; the Autoconf tree is the reference (full feature set + language bindings), Meson is a fast parallel build of the core C library.

Autoconf (reference)

cd build_unix
../dist/configure            # see ../dist/configure --help for options
make -j

# Common variants:
#   --enable-debug --enable-diagnostic   developer build with assertions
#   --enable-cxx                          C++ API
#   --enable-sql                          SQL (SQLite-compatible) API
#   --enable-test --with-tcl=<dir>        build the TCL test harness

make docs                    # render docs_src/ -> docs-build/ (needs pandoc)
make bench                   # build the test/bench microbenchmark drivers
make compdb                  # compile_commands.json for clangd (needs bear)

Meson / Ninja (core C library)

meson setup build            # thin root meson.build drives dist/meson.build
ninja -C build               # -> build/dist/libdb.so
ninja -C build docs          # render the docs
ninja -C build bench         # build the microbenchmark drivers

Both dist/meson.build and dist/meson_options.txt-worth of build logic live under dist/ alongside the Autoconf files; the root meson.build is a thin shim that Meson requires at the setup directory (meson_options.txt also stays at the root because Meson binds it to the project() directory).

LSP / clangd: Meson emits build/compile_commands.json automatically after ninja; symlink or point clangd at it (ln -sf build/compile_commands.json .). The Autoconf build has no compilation database, so make compdb (in build_unix) wraps the build with bear to produce a repo-root compile_commands.json. Both are git-ignored.

To read the API and guide documentation, build it from the Markdown source under docs_src/ (make docs for Autoconf or ninja docs for Meson — see above) and open docs-build/html/index.html in a browser. The rendered reference is also published at https://libdb.org/reference/.

Testing

cd build_unix
../dist/configure --enable-debug --enable-test --with-tcl=/usr/lib/tcl8.6 && make -j
tclsh
  % source ../test/tcl/test.tcl
  % ssi001        ;# SSI write-skew test
  % run_std       ;# the standard suite (long)

Contributing

See .github/CONTRIBUTING.md. PRs target master, are built across the CI matrix (Linux/macOS/Windows, multiple compilers and configure options), and are reviewed by maintainers and the automated OCR reviewer.

License

Berkeley DB is distributed under its original license; see LICENSE. Per-component and bundled-code licenses (BSD, Harvard, CDDL, ASM, and the Berkeley DB license in HTML form) are collected under LICENSES/. Individual archived versions carry the license in effect for that release.