chore(deps): bump redb from 2.6.2 to 3.0.0

[dependabot]

Bumps redb from 2.6.2 to 3.0.0.

Release notes

Sourced from redb's releases.

3.0.0 - 2025-08-09

Removes support for file format v2.

Use Database::upgrade(), in redb 2.6, to migrate to the v3 file format.

General storage optimizations

The v3 file format has been further optimized to reduce the size of the database. Databases with only a few small keys will see the largest benefit, and the minimum size of a database file has decreased from ~2.5MiB to ~50KiB. To achieve the smallest file size call Database::compact() before dropping the Database.

Additionally, performance is ~15% better in bulk load benchmarks. This was achieved by implementing a custom hash function for various in-memory HashSets and HashMaps, and by optimizing the usage of buffers held in Arcs to reduce the number of atomic instructions executed.

Optimize storage of tuple types

Storage of variable width tuple types with arity greater than 1 is more efficient. The new format elides the length of any fixed width fields and uses varint encoding for the lengths of all variable width fields.

Note that this encoding is not compatible with the serialization of variable width tuples used in prior versions. To load tuple data created prior to version 3.0, wrap them in the Legacy type. For example, TableDefinition<u64, (&str, u32)> becomes TableDefinition<u64, Legacy<(&str, u32)>>. Fixed width tuples, such as (u32, u64) are backwards compatible.

Derive for Key and Value traits

Key and Value can be derived using the redb-derive crate. Note that it does not support schema migration. The recommended pattern to migrate schema is to create a new table, and then perform a migration from the old table to the new table.

Read-only multi-process support

Multiple processes may open the same database file for reading by using the new ReadOnlyDatabase type. On platforms which support file locks, this acquires a shared lock on the database file.

Enable garbage collection in Durability::None transactions

Non-durable transactions will now free pages when possible (pages allocated in a preceding non-durable transaction which are no longer referenced). This resolves an issue where a long sequence of non-durable transactions led to significant growth in the size of the database file. This change increases the RAM required for a sequence of non-durable transactions, such that RAM proportional to the net change in the database is now used. However, it will never use more than about 0.2% of the database file size.

Other changes

• Add ReadOnlyDatabase
• Add Builder::open_read_only()
• Add StorageBackend::close()
• Add Table::get_mut()
• Add chrono_v0_4 feature flag which enables serialization of the NaiveDate, NaiveTime,

... (truncated)

Changelog

Sourced from redb's changelog.

3.0.0 - 2025-08-09

Removes support for file format v2.

Use Database::upgrade(), in redb 2.6, to migrate to the v3 file format.

General storage optimizations

The v3 file format has been further optimized to reduce the size of the database. Databases with only a few small keys will see the largest benefit, and the minimum size of a database file has decreased from ~2.5MiB to ~50KiB. To achieve the smallest file size call Database::compact() before dropping the Database.

Additionally, performance is ~15% better in bulk load benchmarks. This was achieved by implementing a custom hash function for various in-memory HashSets and HashMaps, and by optimizing the usage of buffers held in Arcs to reduce the number of atomic instructions executed.

Optimize storage of tuple types

Storage of variable width tuple types with arity greater than 1 is more efficient. The new format elides the length of any fixed width fields and uses varint encoding for the lengths of all variable width fields.

Note that this encoding is not compatible with the serialization of variable width tuples used in prior versions. To load tuple data created prior to version 3.0, wrap them in the Legacy type. For example, TableDefinition<u64, (&str, u32)> becomes TableDefinition<u64, Legacy<(&str, u32)>>. Fixed width tuples, such as (u32, u64) are backwards compatible.

Derive for Key and Value traits

Key and Value can be derived using the redb-derive crate. Note that it does not support schema migration. The recommended pattern to migrate schema is to create a new table, and then perform a migration from the old table to the new table.

Read-only multi-process support

Multiple processes may open the same database file for reading by using the new ReadOnlyDatabase type. On platforms which support file locks, this acquires a shared lock on the database file.

Enable garbage collection in Durability::None transactions

Non-durable transactions will now free pages when possible (pages allocated in a preceding non-durable transaction which are no longer referenced). This resolves an issue where a long sequence of non-durable transactions led to significant growth in the size of the database file. This change increases the RAM required for a sequence of non-durable transactions, such that RAM proportional to the net change in the database is now used. However, it will never use more than about 0.2% of the database file size.

Other changes

• Add ReadOnlyDatabase
• Add Builder::open_read_only()
• Add StorageBackend::close()
• Add Table::get_mut()
• Add chrono_v0_4 feature flag which enables serialization of the NaiveDate, NaiveTime,

... (truncated)

Commits

• 1e3d8d8 Bump version to 3.0.0
• 9ae30d7 Bump redb-derive to 0.1.0
• c7b302d Update changelog
• af1dbcf Update changelog
• 1369032 Update readme
• 198df75 support WASI platforms on stable toolchain
• adce3d2 Update changelog
• d6773ef Update benchmarks in README
• 23e9cf1 Add ReadOnlyDatabase and Builder::open_read_only
• ffed962 Use std file_lock
• Additional commits viewable in compare view

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