v0.15.0

The ScyllaDB team is pleased to announce ScyllaDB Rust Driver 0.15.0,
an asynchronous CQL driver for Rust, optimized for Scylla, but also compatible with Apache Cassandra!

Some interesting statistics:

• over 2.516k downloads on crates!
• over 583 GitHub stars!

Changes

Beginning with this release, instead of putting all API-breaking changes into one group, now they are in the proper categories, but labeled as ⚠️ [API-breaking].

Main changes:

New deserialization API

The main change in this release is the deserialization API refactor. Its primary goal was to reduce overhead caused by all rows being eagerly deserialized to type-erased CqlValue type, only then being converted to end user types.
Old traits and structs (FromCqlVal, FromRow, QueryResult - renamed to LegacyQueryResult, RowIterator - renamed to LegacyRowIterator, TypedRowIterator - renamed to LegacyTypedRowIterator) are replaced by new ones (DeserializeValue, DeserializeRow, new QueryResult, QueryPager, TypedRowStream). There are wrappers and helper implementations provided, designed to aid in gradually migrating to new API - see the migration guide in the book for more information. Old traits and structs will be removed in one of future versions.

New serialization API has a benefit of increased efficiency - now, rows are deserialized straight to the end user type, without any copying and allocations on the way.
Another feature is the ability to deserialize rows to borrowed types (e.g. &str or &[u8]).
And the result metadata is now deserialized in the borrowed form, saving even more allocations.

The refactor included:

• ⚠️ [API-breaking] Parametrized Deserialize{Value,Row} with two lifetimes: 'frame and 'metadata separately (#1101).
• ⚠️ [API-breaking] The deserialization refactor was finished (#1088, #1107, #1109, #1093, #1057, #1120, #1118, #1122, #1121).
• ⚠️ [API-breaking] Unified macro attributes' syntax and semantics between serialization and deserialization derive macros (#1119).

Other changes by category:

New features / enhancements:

• ⚠️ [API-breaking] Made ResultMetadata lifetime-generic, which paved a path to deserializing metadata in a borrowed way as an optimisation to save allocations (#1082).
• Exported serialization migration macros that accidentally hadn't been exported before (#1089).
• Exposed public getters to type-erased errors (#1087).
• Trace message is now issued upon successful keepalive (#1092).
• Added SerializeRow impl for Box<T: SerializeRow> (#1105).
• Exposed public getters for execution profile configuration (#1104).
• Allowed public access to the profile associated with an execution profile handle (#1112).

Bug fixes:

• ⚠️ [API-breaking] Fixed driver's logic that bases on error variants returned from query execution (#1075).
• Fixed possible panic in speculative execution (#1086)
• ⚠️ [API-breaking] Disallowed deserializing Counter type to plain i64 for type safety (#1106).
• Fixed logic about ignoring particular error kinds if speculative execution failed (#1124).

API cleanups / better types:

• ⚠️ [API-breaking] Some of our error types were restructured to be more strongly typed (instead of just containing a string) and better reflect the conditions that they appear in. This work will be continued in 0.16. (#1067, #1074, #1054, #1080, #1080, #1117).
• Removed wildcard re-exports of the serialization framework's entities (#1090).
• ⚠️ [API-breaking] Made RetryPolicy stored behind Arc instead of Box (#1103).

Internal API cleanups/refactors:

• Removed paging state parameter from unpaged raw Connection's API (#1084).
• ⚠️ [API-breaking] Fixed unnameable types in our codebase (by making them exposed, unexposing them or deleting them at all) and enabled the unnameable_types clippy lint to prevent having such situation in the future (#1094).
• Tiny optimizations and code refactors (#1108).

Documentation:

• Updated docs theme (#1081, #1110).

CI / developer tool improvements:

• clippy was appeased again (#1072, #1077, #1095).
• Pinned Rust version in book.yml CI workflow (#1096).

Others:

• Rewritten RELEASE.md, so that it now contains up-to-date guide about maintaining and releasing the driver (#1076).
• Bumped MSRV to 1.70 (#1098).
• Added an example showing Counter UPDATE (#1100).

Congrats to all contributors and thanks everyone for using our driver!

---

The source code of the driver can be found here:

• https://github.com/scylladb/scylla-rust-driver
  Contributions are most welcome!

The official crates.io registry entry is here:

• https://crates.io/crates/scylla

Thank you for your attention, please do not hesitate to contact us if you have any questions, issues, feature requests, or are simply interested in our driver!

Contributors since the last release:

commits	author
154	Mikołaj Uzarski
89	Wojciech Przytuła
45	Karol Baryła
26	Piotr Dulikowski
3	David Garcia
1	Daniel Boll
1	Alex Pozhylenkov

v0.14.0

The ScyllaDB team is pleased to announce ScyllaDB Rust Driver 0.14.0,
an asynchronous CQL driver for Rust, optimized for Scylla, but also compatible with Apache Cassandra!

Some interesting statistics:

• over 2.103k downloads on crates!
• over 556 GitHub stars!

Changes

API cleanups / breaking changes:

• Our session & paging API was revamped so that it is more intuitive and robust. Now the type of the query (paged / unpaged) is tied to the method used to execute it (execute_unpaged / execute_single_page / execute_iter) rather than the page size associated with the statement object. Other changes include (#1061):
  • Introduced strongly typed paging state instead of using Bytes.
  • Paging state is explicitly returned from execute_single_page instead of being a field in QueryResult.
  • Made page_size on the statements mandatory and providing the default value.
  • Updated our docs and examples to point users towards paged queries and explaining the issues with unpaged SELECTs. (#1069, #1068)
• Trait SerializeCql was renamed to SerializeValue because old name turned out to be confusing for users. (#1000)
• Features chrono, time and secret were renamed to chrono-04, time-03 and secrecy-08 to allow us to support new major versions of those libraries in the future. (#939)
• Some of our error types were restructured to be more strongly typed (instead of just containing a string) and better reflect the conditions that they appear in. This work will be continued in 0.15. (#1017, #1026)
• QueryResult.col_specs was changed from being a field to a method in order to allow sharing it with PreparedStatement. (#1065)
• Moved ResultMetadata.paging_state field to Rows.paging_state_response. This is because paging state is something that changes on each paged request and should not be cached by PreparedStatement. (#1065)
• Some parts of our upcoming deserialization refactor were merged, resulting in very minor breaking changes in our error types. The rest of deserialization refactor is planned for 0.15. (#970, #1004, #1024, #1065)

New features / enhancements:

• Values that driver sends to server to identify itself in STARTUP message (DRIVER_NAME, DRIVER_VERSION) can now be configured using new SelfIdentity API in SessionBuilder. (#1039)
• Replaced some .unwrap()s with .expect()s in the code generated by our derive macros. This is done to avoid angering unwrap_used clippy lint and to provide better error messages if those panics are ever triggered. (#1055)
  #1019

Documentation:

• Documentation about using timeuuid type was improved. (#980)
• Improved documentation about PreparedStatement. (#986)
• Updated Scylla Sphinx theme to version 1.7. (#994)
• Added support for building documentation on Mac. (#927)

CI / developer tool improvements:

• #1011 fixed some issue with tests and CI:
  • CI now prints versions of used Rust tools so we don't have to wonder what version is running on Github Actions runners again.
  • Disabled tablets in tests that use LWT because Scylla doesn't support it yet, and other minor tablet-related changes.
  • Restricted Tokio version because of regression when [tokio::test] is used with [ntest::timeout]
• #1019 removed aforementioned Tokio version bounds after regression was fixed there.
• Clippy lints that were previously skipped in two places are enabled again because Darling crate that was triggering them was fixed. (#1036)

Others:

• Updated maintainers list in CONTRIBUTING.md. (#997)

Congrats to all contributors and thanks everyone for using our driver!

---

The source code of the driver can be found here:

• https://github.com/scylladb/scylla-rust-driver
  Contributions are most welcome!

The official crates.io registry entry is here:

• https://crates.io/crates/scylla

Thank you for your attention, please do not hesitate to contact us if you have any questions, issues, feature requests, or are simply interested in our driver!

Contributors since the last release:

commits	author
163	Wojciech Przytuła
55	Mikołaj Uzarski
17	Karol Baryła
3	David Garcia
2	Lucas Kent
2	Piotr Dulikowski
1	Daniel Reis
1	Dmitry Kropachev
1	Kailokk

v0.13.2

The ScyllaDB team is pleased to announce ScyllaDB Rust Driver 0.13.2,
an asynchronous CQL driver for Rust, optimized for Scylla, but also compatible with Apache Cassandra!

Some interesting statistics:

• over 2,080k downloads on crates!
• over 554 GitHub stars!

Changes

Bug fixes:

• Made driver issue a warning and continue instead of failing if an invalid peer is encountered in system tables (#1045)
• Fixed bug that paged queries would be broken when the recently introduced use_cached_metadata flag was set on a PreparedStatement(#1063)

Documentation:

• Documented DefaultPolicy (Load Balancing) with a lot of comments intended for developers to understand its logic easier (#1062)

CI / developer tool improvements:

• Appeased Clippy again (#1046)
• Turned tablets off for Counter tests, as tablets do not support Counters yet (#1060)
• Added scylla_cloud_tests to cfg allowlist (after such allowlist was made mandatory) (#1049)
• Fixed semver-checks failure after its unexpected breaking update (#1050, #1051)

Congrats to all contributors and thanks everyone for using our driver!

---

The source code of the driver can be found here:

• https://github.com/scylladb/scylla-rust-driver
  Contributions are most welcome!

The official crates.io registry entry is here:

• https://crates.io/crates/scylla

Thank you for your attention, please do not hesitate to contact us if you have any questions, issues, feature requests, or are simply interested in our driver!

v0.13.1

The ScyllaDB team is pleased to announce ScyllaDB Rust Driver 0.13.1,
an asynchronous CQL driver for Rust, optimized for Scylla, but also compatible with Apache Cassandra!

Some interesting statistics:

• over 1,905k downloads on crates!
• over 545 GitHub stars!

Changes

Bug fixes:

• Made log logger work with the driver again (#992)
• Fixed bug that Batches would be always sent as LOGGED if they contain any unprepared statement (Query) (#1038)
• Fixed two efficiency-related bugs in default load balancing policy (#1037)

Documentation:

• Documented logging with tracing and log libraries and provided an example (#992)

CI / developer tool improvements:

• Silenced mock structs unused warning (#996)
• Appeased Clippy again (#1002 and #1013)
• Turned tablets off for LWT tests, as tablets do not support LWT yet (d20aed54)
• Made LWT tests ignored when testing with tablets, as tablets do not support LWT yet (2bd45560)

Congrats to all contributors and thanks everyone for using our driver!

---

The source code of the driver can be found here:

• https://github.com/scylladb/scylla-rust-driver
  Contributions are most welcome!

The official crates.io registry entry is here:

• https://crates.io/crates/scylla

Thank you for your attention, please do not hesitate to contact us if you have any questions, issues, feature requests, or are simply interested in our driver!

v0.13.0

The ScyllaDB team is pleased to announce ScyllaDB Rust Driver 0.13.0,
an asynchronous CQL driver for Rust, optimized for Scylla, but also compatible with Apache Cassandra!

Some interesting statistics:

• over 1,615k downloads on crates!
• over 520 GitHub stars!

Changes

API cleanups / breaking changes:

• Implemented support for Tablets, a new major architectural feature of Scylla that will be a part of upcoming 6.0 release. This support is required for token (and shard) awareness to work with Tablet-based tables. You can read more about Tablets in a blogpost by Tomasz Grabiec or watch a presentation by Avi Kivity (#937)
• Enabled shard-selecting load balancing. Before, a LoadBalancingPolicy would return a Plan consisting of Nodes;
  now, together with a Node it can optionally specify the Shard to contact as well. This is crucial for proper Tablets support (see above). Main PR #944, with follow up #969
• Token: added constructor and normalization to increase type-safety (#948)
• Removed another unstable dependency, histogram::Histogram, from public API (#935)
• Implemented CQL protocol-level optimisation: prepared statement result metadata can be now used to decode rows. This saves network bandwidth if that option is enabled, because result metadata need not be sent with each DB query result. (#925)
• Removed num_enum dependency. It was unstable, and we managed to do without it, so it no longer appears in the public API. (#931)
• Decreased pub visibility of scylla-cql definitions which weren't intended for access from outside the driver. (#933)

New features / enhancements:

• Improved the FromRow derive macro to suppport structs with unnamed fields. Before, only structs with named fields were supported. (#985)
• testing: Increased timeout for fetching tracing info - Cassandra was so slow in tests that our CI used to fail sometimes... (#966)
• Removed strum and strum_macros dependencies. They were unstable, and we managed to do without it. (#934)

Documentation:

• Got rid of (most) uses of QueryResult::rows. The preferred method is the more type safe QueryResult::rows_typed. Moreover, QueryResult::rows is going to be deprecated in the next release, once the new lazy deserialization framework is introduced. We thus recommend switching to rows_typed wherever possible. (#955)

CI / developer tool improvements:

• Removed unreachable pubs (#958)
• Dealed with chrono deprecations (#951)
• CI: run cargo clean before tests (#929)
• CI: small fixes in semver checks (#942)
• CI: semver_checks now edits its comment instead of posting new one, so that the PR wall is less cluttered. (#952)
• CI: Tracing output is now shown for a test iff the test failed. This is a major aid in debugging in CI. (#959)
• Reverted "CI/Makefile: disable uninlined_format_args clippy lint", as rust-analyzer now properly supports semantic analysis of such format args. (#945)
• Appeased Clippy again (#971)

Congrats to all contributors and thanks everyone for using our driver!

---

The source code of the driver can be found here:

• https://github.com/scylladb/scylla-rust-driver
  Contributions are most welcome!

The official crates.io registry entry is here:

• https://crates.io/crates/scylla

Thank you for your attention, please do not hesitate to contact us if you have any questions, issues, feature requests, or are simply interested in our driver!

Contributors since the last release:

commits	author
40	Karol Baryła
24	Mikołaj Uzarski
10	Wojciech Przytuła
1	Piotr Dulikowski
1	Piotr Grabowski

v0.12.0

The ScyllaDB team is pleased to announce ScyllaDB Rust Driver 0.12.0,
an asynchronous CQL driver for Rust, optimized for Scylla, but also compatible with Apache Cassandra!

Some interesting statistics:

• over 1,156k downloads on crates!
• over 500 GitHub stars; We passed 500 stars!

Changes

API cleanups / breaking changes:

• Introduced CqlTimeuuid type. Timeuuid CQL type now corresponds to the new type instead of Uuid. The purpose of new type is mostly providing correct semantics (matching the database) with regard to sorting / comparing / hashing (#894)
• Public usages of num_bigint::BigInt are now hidden behind feature flag. Support for num_bigint 0.4 is added. You can enable support for chosen version using num-bigint-03 / num-bigint-04 feature flags (#902)
• bigdecimal dependency version is bumped to 0.4. Similarly to BigInt, usages of bigdecimal are now behind feature-flag bigdecimal-04 (#922)

New features / enhancements:

• SerializeRow and SerializeCql derive macros now support skip field attribute to skip some fields during serialization (#903)

Documentation:

• Documentation for SerializeRow / SerializeCql derive macros is now rendered only in scylla crate. Previously it was only visible in scylla-cql due to an oversight, which made it hard to discover for users. It is not possible to render it in both crates without duplicating it in code because of rustdoc limitation (#907)
• Examples now use different table and keyspace names so that running multiple of them on the same cluster works correctly (#846)
• Added section discouraging use of multiple / short-lived Session objects and recommendations about sharing Session objects between threads. You can find this section in Connecting to the cluster page of book (#914)

Bug fixes:

• Some time-related were put behind chrono feature flag instead of time feature flag (#898)
• chrono introduced an arguably breaking change - changing values of NaiveDate::MIN/MAX. We changed our tests to nor rely on those values. If you used those values as markers / placeholders in database, you may not be able to deserialize them with new version ofchrono(#919)

CI / developer tool improvements:

• Purpose of Cargo.lock.msrv file and ways to update this file when min_rust job are now documented in CONTRIBUTING.md (#913)
• Building documentation using Scylla's Sphinx tooling now uses myst parser instead of deprecated recommonmark. One improvement is markdown table support (#874)
• Our documentation must work with Scylla's Sphinx tooling, so it contains ToC (Table of Contents) sections that are not supported by mdbook. In order to be able to build it with mdbook we had a wrapper script that stripped those sections before calling mdbook. Now this script is replaced by preprocessor script called automatically by mdbook - so just calling mdbook commands "just works" again now (#910).
• New Markdown parser for Sphinx parser, and our preprocessor mentioned in previous point, now support warning admonition with the following syntax (#914):

:::{warning}
text
:::

• Fixed new clippy warnings introduced in Rust 1.75 (#900)
• Introduced cargo-semver-checks tool to our CI to decrease the chance of releasing a breaking change after we are at 1.0 (#909)

Congrats to all contributors and thanks everyone for using our driver!

---

The source code of the driver can be found here:

• https://github.com/scylladb/scylla-rust-driver
  Contributions are most welcome!

The official crates.io registry entry is here:

• https://crates.io/crates/scylla

Thank you for your attention, please do not hesitate to contact us if you have any questions, issues, feature requests, or are simply interested in our driver!

Contributors since the last release:

commits	author
31	Mikołaj Uzarski
31	Karol Baryła
13	Piotr Dulikowski
2	Oliver Bøving
1	David Garcia
1	Nick Sippl-Swezey

v0.11.1

Due to our mistake, crate scylla-macros 0.2.2 contained a breaking change, while only being a minor version bump.
This resulted in the driver breaking for some existing projects that use version 0.10.x.
You can find more detailed explanation here: #891

To solve this situation:

• scylla-macros 0.3.0 was released identical to 0.2.2 and 0.2.2 was yanked.
• scylla-cql 0.0.11 was released, the only changed from 0.0.10 is scylla-macros dependency bumped to 0.3.0.
• scylla 0.11.1 was released, the only change from 0.11.0 is updating the scylla-cql and scylla-macros dependencies. 0.11.0 was yanked.

Additionally, we published scylla-macros 0.2.3, equivalent to 0.2.1, to minimize breakage in existing projects.

v0.11.0

The ScyllaDB team is pleased to announce ScyllaDB Rust Driver 0.11.0,
an asynchronous CQL driver for Rust, optimized for Scylla, but also compatible with Apache Cassandra!

Some interesting statistics:

• over 1,018k downloads on crates; We passed a milion downloads!
• over 490 GitHub stars!

Notable changes

The main feature of this PR is refactor of serialization API. Old traits and structs (Value, ValueList, BatchValues - renamed to LegacyBatchValues, SerializedValues - renamed to LegacySerializedValues) are replaced by new ones (SerializeCql, SerializeRow, new BatchValues, new SerializedValues). There are wrappers and helper implementations provided, designed to aid in gradually migrating to new API - see the migration guide in the book for more information. Old traits and structs will be removed in one of future versions.

New serialization API has a benefit of type safety - now, if you use wrong type for a bind marker in a query, you will get an understandable error locally (without actually executing the query on the database) instead of cryptic deserialization error from Scylla, or worse - silent data corruption.

API cleanups / breaking changes:

• Improved support of common time and date crates - thanks Anfid for contribution (745)

New features / enhancements:

• Check count of batch statements locally and reject too long batches without contacting the server. This PR also changes some improper usages of i16 to u16 (#824)
• Implement Default for MaybeUnset (#883)

Documentation:

• Updated Sphinx theme to 1.6 (#827)
• Removed usage of illegal consistency level in an example (#840)
• Removed redundant explicit link target in documentation (#848)
• Updated UDT example to be in line with docs (#849)
• Fixed a lot of typos (#876)

Bug fixes:

• Manually dereference Option<&&str> in one place to work around possible rustc bug (#838)

CI / developer tool improvements:

• Set workspace cargo resolver to version = 2 in order to get rid of annoying warning (#833)
• Improved error handling in test_coalescing (#834)
• Fix benchmarks compilation and compile them in CI to prevent further errors (#853)
• Use latest Cassandra version again, as the new version fixed the problem that made our tests fail (#850)
• Fix clippy new warning needless_borrows_for_generic_args (#861)
• Added possibility to filter out control connection messages to the proxy (#863)
• Commited renamed Cargo.lock file to be used in MSRV testing (#856)
• Compile benchmarks when calling make ci so that developers can notice errors while testing locally (#877)
• Pass the hostname of the container when checking for its health with cqlsh to unblock CI (#873)

Congrats to all contributors and thanks everyone for using our driver!

---

The source code of the driver can be found here:

• https://github.com/scylladb/scylla-rust-driver
  Contributions are most welcome!

The official crates.io registry entry is here:

• https://crates.io/crates/scylla

Thank you for your attention, please do not hesitate to contact us if you have any questions, issues, feature requests, or are simply interested in our driver!

Contributors since the last release:

commits	author
116	Piotr Dulikowski
67	Karol Baryła
5	Jan Ciołek
5	Sylwia Szunejko
1	David Garcia
1	Mikhail Pogretskiy
1	Nick Sippl-Swezey
1	Oliver Bøving
1	RoDmitry
1	Samuel Orji
1	Yaniv Kaul

v0.10.1

Changes

• Fixed a panic in LatencyAwarePolicy when 2 calls to Instant::now() returned the same value. (#830)

v0.9.1

Changes

• Fixed a panic in LatencyAwarePolicy when 2 calls to Instant::now() returned the same value. (#830)