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) — an opt-in DB_TXN_SNAPSHOT_SAFE transaction mode that 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 DB_TXN_SNAPSHOT_SAFE is rejected with prepare()/2PC. 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 lab/bench/ssi_abort_bench), and the HA/replication qualification is still being built. This is the first of the planned features in ROADMAP.md, which targets matching or beating InnoDB and WiredTiger on multicore/NUMA scalability and performance.

Building

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

To view the original distribution and API documentation, open docs/index.html in a browser.

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. Individual archived versions carry the license in effect for that release.