heed & heed3

This release brings a new functionality: the possibility to create multiple nested read transactions from an uncommitted write transaction. You can also examine another usage in the dedicated example file.

We finally merged the changes to upstream LMDB (mdb.master3), and the patch has been thoroughly reviewed by Howard Chu.

// opening a write transaction
let mut wtxn = env.write_txn()?;

// [use the RwTxn to write into the env]

// opening multiple read-only transactions without committing beforehand
let rtxns = (0..1000).map(|_| env.nested_read_txn(&wtxn)).collect::<heed::Result<Vec<_>>>()?;

// you can also spawn nested read transactions from the write txn too
let rtxns = (0..1000).map(|_| wtxn.nested_read_txn()).collect::<heed::Result<Vec<_>>>()?;

// [use the RoTxns and move them onto different threads]

heed & heed3

This release brings a new experimental functionality: the possibility to create multiple nested read transactions from an uncommitted write transaction. You can also examine another usage in the dedicated example file or in this Meilisearch pull request.

We are attempting to merge the necessary changes to upstream LMDB, but it will require additional work to ensure it produces correct C code. You can review the dedicated OpenLDAP tracking issue to see how it progresses.

// opening a write transaction
let mut wtxn = env.write_txn()?;

// [use the RwTxn to write into the env]

// opening multiple read-only transactions without committing beforehand
let rtxns = (0..1000).map(|_| env.nested_read_txn(&wtxn)).collect::<heed::Result<Vec<_>>>()?;

// [use the RoTxns and move them onto different threads]

heed & heed3

This release brings better-polished support for the heed/heed3 duality. It also improves the documentation, adds support for custom duplicate sort comparators, supports the PREV_SNAPSHOT flag, better support for Thread Local Storage (TLS)-backed of transactions, and bumps LMDB to the latest patch.

What's Changed

• Combined version of LMDB mdb.master and mdb.master3 by @Kerollmops in #278
• Upgrade dependencies by @Kerollmops in #295, #304, #320, and #303
• List the examples in the Cargo tomls by @Kerollmops in #298
• Parametric TLS for read transactions by @Kerollmops in #300
• Fix the MDB_NOTLS documentation by @Kerollmops in #302
• Update license for 2025 by @meili-bot in #305
• Bump LMDB commit, use GitLab for LMDB and improve the build script by @Kerollmops in #310 and #311
• Break and improve the Env::copy_to_file method by @Kerollmops in #312
• Introduce the PREV_SNAPSHOT flag by @irevoire in #296
• Rename FIXED_MAP flag name by @Kerollmops in #313
• Expose USE_VALGRIND compilation flag as use-valgrind feature by @dureuill in #288
• Introduce AnyTls by @dureuill in #315
• Show ranges of slice in the doc by @Kerollmops in #318
• More Env parameter accessors by @Kerollmops in #321
• Setting NDEBUG on release builds by @Kerollmops in #324
• Bump -sys crates and heed/heed3 versions by @Kerollmops in #325
• Introduce the Env::copy_to_path method by @Kerollmops in #326
• Make the Env<WithTls> the default by @Kerollmops in #327
• Add Dup Sort Custom Comparator support by @Kerollmops and @oXtxNt9U in #319

Full Changelog: v0.21.0...v0.22.0

heed & heed3

This release introduces the first wrapper around the mdb.master3 LMDB branch, which features encryption at rest. You can use the new heed3 crate to read and write data encrypted on disk and decrypted on demand.

What's Changed

• Make the RoTxn covariant and keep it !Sync by @Kerollmops in #285
• Relax the HeedDecode bound on Lazy::remap by @irevoire in #287
• add custom ordering support to range types by @Boog900 in #289

New Contributors

• @Boog900 made their first contribution in #289

Full Changelog: v0.20.5...v0.21.0