--- metadata: - name: generator content: Diplodoc Platform v5.50.6 alternate: - https://ydb.tech/docs/en/changelog-server.md - https://ydb.tech/docs/ru/changelog-server.md sourcePath: en/core/changelog-server.md --- > **Documentation Index:** Fetch the complete configuration index at https://ydb.tech/docs/en/llms.txt # YDB Server changelog ## Version 26.1 {#26-1} ### Version 26.1.1.22 {#26-1-1-22} Release date: July 27, 2026. #### Bug Fixes * [Fixed](https://github.com/ydb-platform/ydb/pull/46894) Kafka API authentication for local users: with enabled `DomainLoginOnly` setting, users could not access tenant databases. * [Fixed](https://github.com/ydb-platform/ydb/pull/46946) a crash (use-after-free) when updating a vector index caused by asynchronous ReadActor destruction. ### Version 26.1.1.20 {#26-1-1-20} Release date: July 2, 2026. #### Functionality * YQL statements [`SHOW CREATE TABLE`](https://ydb.tech/docs/en/yql/reference/syntax/show_create.md?version=v26.1) and [`SHOW CREATE VIEW`](https://ydb.tech/docs/en/yql/reference/syntax/show_create.md?version=v26.1) return the DDL required to recreate a table or view. * `ALTER TABLE` supports default values in [`ADD COLUMN`](https://ydb.tech/docs/en/yql/reference/syntax/alter_table/columns.md?version=v26.1) (`DEFAULT`). * [Shuffle Elimination](https://ydb.tech/docs/en/concepts/query_execution/optimizer.md?version=v26.1) is enabled in production: the optimizer can remove unnecessary data shuffles in joins. * [Backup and restore](https://ydb.tech/docs/en/reference/ydb-cli/export-import/file-structure.md?version=v26.1) now cover [asynchronous replications](https://ydb.tech/docs/en/concepts/async-replication.md?version=v26.1), [external data sources](https://ydb.tech/docs/en/concepts/datamodel/external_data_source.md?version=v26.1), [external tables](https://ydb.tech/docs/en/concepts/datamodel/external_table.md?version=v26.1), and [transfers](https://ydb.tech/docs/en/concepts/transfer.md?version=v26.1). * The cluster keeps running when [CMS](https://ydb.tech/docs/en/concepts/glossary.md?version=v26.1#cms) is unavailable. * [Dynamic nodes](https://ydb.tech/docs/en/devops/configuration-management/configuration-v1/node-authorization.md?version=v26.1) can be registered using client TLS certificates. * [LDAP service account authentication](https://ydb.tech/docs/en/security/authentication.md?version=v26.1) supports the SASL EXTERNAL mechanism — see [`enable_sasl_external_bind`](https://ydb.tech/docs/en/reference/configuration/auth_config.md?version=v26.1#ldap-auth-config). * [Asynchronous replication](https://ydb.tech/docs/en/concepts/async-replication.md?version=v26.1) mirroring supports [auto-partitioned topics](https://ydb.tech/docs/en/concepts/datamodel/topic.md?version=v26.1#autopartitioning); see also [topic partitions in CDC](https://ydb.tech/docs/en/concepts/cdc.md?version=v26.1#topic-partitions). * [TLI](https://ydb.tech/docs/en/reference/configuration/tli_config.md?version=v26.1) (Transaction Lock Invalidation) diagnostics were extended: `tli_config`, [logging](https://ydb.tech/docs/en/troubleshooting/performance/queries/tli-logging.md?version=v26.1), and [system views](https://ydb.tech/docs/en/dev/system-views.md?version=v26.1#top-tli-partitions). * [Load-based auto-partitioning](https://ydb.tech/docs/en/concepts/datamodel/table.md?version=v26.1#auto_partitioning_by_load) considers CPU load on the partition leader and all its replicas. * [Streaming queries](https://ydb.tech/docs/en/dev/streaming-query/index.md?version=v26.1) support [writing results to local tables](https://ydb.tech/docs/en/dev/streaming-query/table-writing.md?version=v26.1). * [Changefeeds (CDC)](https://ydb.tech/docs/en/concepts/cdc.md?version=v26.1) can export user security identifiers (`USER_SIDS`) — see [`ALTER TABLE` `CHANGEFEED`](https://ydb.tech/docs/en/yql/reference/syntax/alter_table/changefeed.md?version=v26.1). * [External data sources](https://ydb.tech/docs/en/concepts/datamodel/external_data_source.md?version=v26.1) support `AUTH_METHOD=IAM`. * CLI supports token file authentication (`--token-file`). * Transaction handling between topics and tables has been optimized. #### Bug Fixes * [Fixed](https://github.com/ydb-platform/ydb/pull/34906) `RETURNING` in streaming `UPDATE` and interactive queries. * [Fixed](https://github.com/ydb-platform/ydb/pull/34915) `SET DEFAULT` and `DROP DEFAULT` in `ALTER TABLE`. * [Fixed](https://github.com/ydb-platform/ydb/pull/34958) auth token expiry handling in the ticket parser. * [Fixed](https://github.com/ydb-platform/ydb/pull/35003) query execution in Workload Manager after tenant recreation. * [Fixed](https://github.com/ydb-platform/ydb/pull/35187) a use-after-free in the gRPC service layer. * [Fixed](https://github.com/ydb-platform/ydb/pull/35663) incremental restore surviving SchemeShard restarts and shard failures. * [Fixed](https://github.com/ydb-platform/ydb/pull/35787) streaming query metadata missing immediately after creation. * [Fixed](https://github.com/ydb-platform/ydb/pull/35793) async checkpointing stalling when input is full and the checkpoint is empty. * [Fixed](https://github.com/ydb-platform/ydb/pull/36217) cross-database quota interference in the Kesus quoter proxy. * [Fixed](https://github.com/ydb-platform/ydb/pull/36220) hangs in PQ read sessions. * [Fixed](https://github.com/ydb-platform/ydb/pull/36292) scan executor hangs on `SELECT … LIMIT` over empty tables. * [Fixed](https://github.com/ydb-platform/ydb/pull/36692) TLI deferred `LOCKS_BROKEN` flush accounting. * [Fixed](https://github.com/ydb-platform/ydb/pull/37130) streaming query timeout overflow. * [Fixed](https://github.com/ydb-platform/ydb/pull/37145) thread safety and token expiry parsing in the IAM credentials provider. * [Fixed](https://github.com/ydb-platform/ydb/pull/37285) errors in the HTTP gateway. * [Fixed](https://github.com/ydb-platform/ydb/pull/37668) integer overflow when handling null passwords. * [Fixed](https://github.com/ydb-platform/ydb/pull/38033) CDC collection disabled for `IsBuildInProgress` columns. * [Fixed](https://github.com/ydb-platform/ydb/pull/38490) segfault during updates. * [Fixed](https://github.com/ydb-platform/ydb/pull/38544) Shuffle Elimination with the `HashJoinMode` pragma. * [Fixed](https://github.com/ydb-platform/ydb/pull/39337) duplicated rows in scan queries after delivery issues. * [Fixed](https://github.com/ydb-platform/ydb/pull/39687) viewer HTTP endpoints restricted to viewer/admin SIDs; database scope enforced for database-only tokens. * [Fixed](https://github.com/ydb-platform/ydb/pull/39798) OOM when loading trash on blob depot. * [Fixed](https://github.com/ydb-platform/ydb/pull/41681) `TQueryBase` crash after cancelling a streaming query. * [Fixed](https://github.com/ydb-platform/ydb/pull/43068) local CDC reads from YQL. * [Fixed](https://github.com/ydb-platform/ydb/pull/44340) quick remote cancellation in the query service. ## Version 25.4 {#25-4} ### Version 25.4.1.15 {#25-4-1-15} Release date: June 5, 2026. #### Functionality * YQL statements [`BATCH UPDATE`](https://ydb.tech/docs/en/yql/reference/syntax/batch-update.md?version=v25.4) and [`BATCH DELETE FROM`](https://ydb.tech/docs/en/yql/reference/syntax/batch-delete.md?version=v25.4) are available for bulk updates and deletes in tables. * The write execution path has changed substantially: writes now run in streaming mode without fully materializing data on the Query Processor side before sending it to DataShards, which improves performance for large write workloads. The change applies to a subset of scenarios; in some cases (for example, tables with secondary indexes) the previous approach is still used. For an overview of the execution pipeline, see [Query execution](https://ydb.tech/docs/en/concepts/query_execution/index.md?version=v25.4). * Lookup Join execution was optimized: it uses a streaming mode without materializing one side of the join, which lowers peak memory use, speeds up queries over large datasets, and removes previous limits on join side sizes. See [Index lookup Join](https://ydb.tech/docs/en/faq/yql.md?version=v25.4#index-lookup-join) and the [`JOIN`](https://ydb.tech/docs/en/yql/reference/syntax/select/join.md?version=v25.4) operator syntax. * You can now configure access permissions for cluster and database [system views](https://ydb.tech/docs/en/devops/observability/system-views.md?version=v25.4). * Row-oriented tables support configurable [cache modes](https://ydb.tech/docs/en/concepts/datamodel/table.md?version=v25.4#cache-modes), including a new `in_memory` mode that preloads table data into RAM when sufficient memory is available. * Topic consumers gained an [`availability-period`](https://ydb.tech/docs/en/reference/ydb-cli/topic-consumer-add.md?version=v25.4) parameter that extends retention of uncommitted messages beyond `retention-period`. * [Per-partition topic metrics and export to user shard quotas](https://ydb.tech/docs/en/reference/observability/metrics/index.md?version=v25.4#topics_partitions) are available for accounting and observability. * Faster queries with `LIMIT` on column-oriented tables through early result limiting on storage nodes (for queries with no sort or with sort by primary key). See [`LIMIT` and `OFFSET`](https://ydb.tech/docs/en/yql/reference/syntax/select/limit_offset.md?version=v25.4) in YQL. * Column-oriented tables support the `Bool` type in schema and queries — see [primitive YQL types](https://ydb.tech/docs/en/yql/reference/types/primitive.md?version=v25.4#numeric). * A [filtered vector index](https://ydb.tech/docs/en/dev/vector-indexes.md?version=v25.4#filtered) correctly returns rows inserted after the index was created when filter column values are new. * Stream processing and data delivery are more tightly integrated into the core: [topic → table transfer](https://ydb.tech/docs/en/concepts/transfer.md?version=v25.4); [streaming queries](https://ydb.tech/docs/en/dev/streaming-query/index.md?version=v25.4) are available to users when `EnableStreamingQueries` is enabled. * The `overlap_clusters` option substantially improves vector search quality by placing vectors in multiple index clusters (index settings) — see [Vector indexes](https://ydb.tech/docs/en/dev/vector-indexes.md?version=v25.4). * Vector index search is significantly faster across all index types because distances are computed locally on each DataShard before data is sent over the network — see [VIEW (vector index)](https://ydb.tech/docs/en/yql/reference/syntax/select/vector_index.md?version=v25.4) and [Vector indexes](https://ydb.tech/docs/en/dev/vector-indexes.md?version=v25.4). * Full vector search without an ANN index is faster thanks to pushdown (vector search, KNN UDF) — see [Vector search](https://ydb.tech/docs/en/concepts/query_execution/vector_search.md?version=v25.4) and the [KNN](https://ydb.tech/docs/en/yql/reference/udf/list/knn.md?version=v25.4) module. * Database-stored secrets are fully supported (create, alter, drop, and use) — see [Secrets](https://ydb.tech/docs/en/concepts/datamodel/secrets.md?version=v25.4). Note that the [legacy syntax](https://ydb.tech/docs/en/concepts/datamodel/secrets.md?version=v25.3) is deprecated. * [`UNION ALL`](https://ydb.tech/docs/en/yql/reference/syntax/select/union.md?version=main#union-all) execution was improved with parallel execution, improving performance of analytical queries. #### Bug Fixes * [Fixed](https://github.com/ydb-platform/ydb/pull/38425) an [LDAP authentication](https://ydb.tech/docs/en/security/authentication.md) vulnerability: knowing the login and password of any LDAP user (including one who is not a member of a group allowed to access YDB), an attacker could bypass group membership checks and gain access to the cluster (LDAP search filter injection; special characters are now escaped per RFC 2254). ## Version 25.3 {#25-3} ### Version 25.3.1.27 {#25-3-1-27} Release date: May 20, 2026. #### Functionality * Added support for two–data center configuration with synchronous data writes (Bridge mode). Available in YDB Enterprise. * Topic improvements: * In Kafka API [compacted](https://docs.confluent.io/kafka/design/log_compaction.html#ak-log-compaction) topics can now be created, and YDB automatically creates and removes the internal service consumer used for topic compaction; * Topic APIs were extended with new `DescribeConsumer` and [per-partition topic metrics can now be exported into user quotas](https://ydb.tech/docs/en/reference/observability/metrics/index.md#topics). * Implemented [backup and restore](https://ydb.tech/docs/en/reference/ydb-cli/export-import/file-structure.md?version=v25.3#topics) of topic configuration to and from S3; * Implemented [backup and restore](https://ydb.tech/docs/en/reference/ydb-cli/export-import/file-structure.md#views) (`VIEW`) to S3 and from S3. #### Bug Fixes * [Fixed](https://github.com/ydb-platform/ydb/pull/38425) an [LDAP authentication](https://ydb.tech/docs/en/security/authentication.md) vulnerability: knowing the login and password of any LDAP user (including one who is not a member of a group allowed to access YDB), an attacker could bypass group membership checks and gain access to the cluster (LDAP search filter injection; special characters are now escaped per RFC 2254). * [Fixed](https://github.com/ydb-platform/ydb/pull/33758) an issue that caused a server-side session leak. * [Fixed](https://github.com/ydb-platform/ydb/pull/36926) an issue where, in rare cases, reads from a table could block its deletion. * [Fixed](https://github.com/ydb-platform/ydb/pull/20238) a race condition when updating the CPU soft limit. * [Fixed behavior](https://github.com/ydb-platform/ydb/pull/18121), where `ALTER TABLE` could fail for tables with a vector index. * [Fixed](https://github.com/ydb-platform/ydb/pull/18088) nconsistent results in some read-write transactions — conflicting writes no longer overwrite uncommitted changes. * [Fixed](https://github.com/ydb-platform/ydb/pull/18234) serializability violations in read-write transactions after shard restarts. * [Fixed](https://github.com/ydb-platform/ydb/pull/20560) a memory management issue when committing offsets in topics with automatic partitioning enabled. * [Added](https://github.com/ydb-platform/ydb/pull/18698) checks for enabled encryption in zero-copy transfers. * [Fixed](https://github.com/ydb-platform/ydb/pull/20519) an issue that could cause a VDisk to hang in local recovery after a ChunkRead error. * [Eliminated](https://github.com/ydb-platform/ydb/pull/18924) phantom VDisk appearances caused by race conditions between group creation and deletion operations. * [Improved](https://github.com/ydb-platform/ydb/pull/17687) phantom VDisks caused by races between group creation and deletion operations. * When a session ends via attach stream, a notification is now [sent](https://github.com/ydb-platform/ydb/pull/22298). * The coordination service now correctly [returns](https://github.com/ydb-platform/ydb/pull/16901) `SCHEME_ERROR` for non-existent resources instead of the incorrect `INTERNAL_ERROR` code. * [Fixed](https://github.com/ydb-platform/ydb/pull/20157) memory handling issues and internal data consistency violations in Workload Manager and related scheduler code. * [Fixed](https://github.com/ydb-platform/ydb/pull/20432) an issue where PDisk info requests could time out when the target node was disabled or unavailable. ## Version 25.2 {#25-2} ### Version 25.2.1.24 {#25-2-1-24} Release date: January 28, 2026. #### Bug Fixes * [Fixed](https://github.com/ydb-platform/ydb/pull/25112) an [issue](https://github.com/ydb-platform/ydb/issues/23858) where [tablet](https://ydb.tech/docs/en/concepts/glossary.md#tablet) deletion might get stuck * [Fixed](https://github.com/ydb-platform/ydb/pull/25145) an [issue](https://github.com/ydb-platform/ydb/issues/20866) that caused an error when changing a table's follower * Fixed a couple of [changefeed](https://ydb.tech/docs/en/concepts/glossary.md#changefeed) related issues: * [Fixed](https://github.com/ydb-platform/ydb/pull/25689) an [issue](https://github.com/ydb-platform/ydb/issues/25524) where importing a table with a Utf8 primary key and an enabled changefeed could fail * [Fixed](https://github.com/ydb-platform/ydb/pull/25453) an [issue](https://github.com/ydb-platform/ydb/issues/25454) where importing a table without changefeeds could fail due to incorrect changefeed file lookup. * [Fixed](https://github.com/ydb-platform/ydb/pull/26069) an [issue](https://github.com/ydb-platform/ydb/issues/25869) that could cause errors during UPSERT operations in column tables. * [Fixed](https://github.com/ydb-platform/ydb/pull/26504) an [error](https://github.com/ydb-platform/ydb/issues/26225) that could cause a crash due to accessing freed memory * [Fixed](https://github.com/ydb-platform/ydb/pull/26657) an [issue](https://github.com/ydb-platform/ydb/issues/23122) with duplicates in unique secondary index * [Fixed](https://github.com/ydb-platform/ydb/pull/26879) an [issue](https://github.com/ydb-platform/ydb/issues/26565) with checksum mismatch error on restoration compressed backup from s3 * [Fixed](https://github.com/ydb-platform/ydb/pull/27528) an [issue](https://github.com/ydb-platform/ydb/issues/27193) where some queries from the TPC-H 1000 benchmark could fail * Fixed a couple of cluster bootstrap related issues: * [Fixed](https://github.com/ydb-platform/ydb/pull/25678) an [issue](https://github.com/ydb-platform/ydb/issues/25023) where cluster bootstrap could hang when mandatory authorization was enabled. * [Fixed](https://github.com/ydb-platform/ydb/pull/28886) an [issue](https://github.com/ydb-platform/ydb/issues/27228) where it was impossible to create new databases for several minutes immediately after cluster deployment * [Fixed](https://github.com/ydb-platform/ydb/pull/28655) an [issue](https://github.com/ydb-platform/ydb/issues/28510) where race condition could occur and clients receive `Could not find correct token validator` error when mising newly issued tokens before `LoginProvider` state is updated. * [Fixed](https://github.com/ydb-platform/ydb/pull/29940) an [issue](https://github.com/ydb-platform/ydb/issues/29903) where named expression containing another named expression caused incorrect `VIEW` backup ### Release candidate 25.2.1.10 {#25-2-1-10-rc} Release date: September 21, 2025. #### Functionality * [Analytical capabilities](https://ydb.tech/docs/en/concepts/analytics/index.md) are available by default: [column-oriented tables](https://ydb.tech/docs/en/concepts/datamodel/table.md#column-oriented-tables) can be created without special flags, using LZ4 compression and hash partitioning. Supported operations include a wide range of DML operations (UPDATE, DELETE, UPSERT, INSERT INTO ... SELECT) and CREATE TABLE AS SELECT. Integration with dbt, Apache Airflow, Jupyter, Superset, and federated queries to S3 enables building end-to-end analytical pipelines in YDB. * [Cost-Based Optimizer](https://ydb.tech/docs/en/concepts/query_execution/optimizer.md) is enabled by default for queries involving at least one column-oriented table but can also be enabled manually for other queries. The Cost-Based Optimizer improves query performance by determining the optimal join order and join types based on table statistics; supported [hints](https://ydb.tech/docs/en/dev/query-execution-optimization/query-hints.md) allow fine-tuning execution plans for complex analytical queries. * Added YDB Transfer – an asynchronous mechanism for transferring data from a topic to a table. You can create a transfer, update or delete it using YQL commands. * Added [spilling](https://ydb.tech/docs/en/concepts/query_execution/spilling.md), a memory management mechanism, that temporarily offloads intermediate data arising from computations and exceeding available node RAM capacity to external storage. Spilling allows executing user queries that require processing large data volumes exceeding available node memory. * Increased the [maximum amount of time allowed for a single query to execute](./concepts/limits-ydb) from 30 minutes to 2 hours. * Added support for a user-defined Certificate Authority (CA) and [Yandex Cloud Identity and Access Management (IAM)](https://yandex.cloud/ru/docs/iam) authentication in [asynchronous replication](https://ydb.tech/docs/en/yql/reference/syntax/create-async-replication.md). * Enabled by default: * [vector index](https://ydb.tech/docs/en/dev/vector-indexes.md) for approximate vector similarity search, * support for [client-side consumer balancing](https://www.confluent.io/blog/cooperative-rebalancing-in-kafka-streams-consumer-ksqldb), [compacted topics](https://docs.confluent.io/kafka/design/log_compaction.html) and [transactions](https://www.confluent.io/blog/transactions-apache-kafka/) in [YDB Topics Kafka API](https://ydb.tech/docs/en/reference/kafka-api/index.md), * support for [auto-partitioning topics](https://ydb.tech/docs/en/concepts/cdc.md#topic-partitions) for row-oriented tables in CDC, * support for auto-partitioning topics in asynchronous replication, * support for [parameterized Decimal type](https://ydb.tech/docs/en/yql/reference/types/primitive.md#numeric), * support for [Datetime64 data type](https://ydb.tech/docs/en/yql/reference/types/primitive.md#datetime), * automatic cleanup of temporary tables and directories during export to S3, * support for [changefeeds](https://ydb.tech/docs/en/concepts/cdc.md) in backup and restore operations, * the ability to [enable followers (read replicas)](https://ydb.tech/docs/en/yql/reference/syntax/alter_table/indexes.md) for covered secondary indexes, * system views with [history of overloaded partitions](https://ydb.tech/docs/en/dev/system-views.md#top-overload-partitions). #### Bug Fixes * [Fixed](https://github.com/ydb-platform/ydb/pull/24265) CPU resource limiting for column-oriented tables in Workload Manager. Previously CPU consumption could exceed the configured limits. ## Version 25.1 {#25-1} ### Version 25.1.4.7 {#25-1-4-7} Release date: September 15, 2025. #### Functionality * [Added](https://github.com/ydb-platform/ydb/pull/21119) support for the Kafka frameworks, such as Kafka Connect, Kafka Streams, Confluent Schema Registry, Kafka Streams, Apache Flink, etc. Now [YDB Topics Kafka API](https://ydb.tech/docs/en/reference/kafka-api/index.md) supports the following features: * client-side consumer balancing. To enable it, use the `enable_kafka_native_balancing` flag in the [cluster configuration](https://ydb.tech/docs/en/reference/configuration/index.md). For for information, see [How consumer balancing works in Apache Kafka](https://www.confluent.io/blog/cooperative-rebalancing-in-kafka-streams-consumer-ksqldb/). When enabled, consumer balancing will work the same way in YDB Topics. * [compacted topics](https://docs.confluent.io/kafka/design/log_compaction.html). To enable topic compaction, use the `enable_topic_compactification_by_key` flag. * [transactions](https://www.confluent.io/blog/transactions-apache-kafka/). To enable transactions, use the `enable_kafka_transactions` flag. * [Added](https://github.com/ydb-platform/ydb/pull/20982) a [new protocol](https://github.com/ydb-platform/ydb/issues/11064) to [Node Broker](https://ydb.tech/docs/en/concepts/glossary.md#node-broker) that eliminates the long startup of nodes on large clusters (more than 1000 servers). #### YDB UI * [Fixed](https://github.com/ydb-platform/ydb/pull/17839) an [issue](https://github.com/ydb-platform/ydb-embedded-ui/issues/18615) where not all tablets are shown for pers queue group on the tablets tab in diagnostics. * Fixed an [issue](https://github.com/ydb-platform/ydb/issues/18735) where the storage tab on the diagnostics page displayed nodes of other types in addition to storage nodes. * Fixed a [serialization issue](https://github.com/ydb-platform/ydb-embedded-ui/issues/2164) that caused an error when opening query execution statistics. * Changed the logic for nodes transitioning to critical state – the CPU pool, which is 75-99% full, now triggers a warning, not a critical state. #### Performance * [Optimized](https://github.com/ydb-platform/ydb/pull/20197) processing of empty inputs when performing JOIN operations. #### Bug fixes * [Added support](https://github.com/ydb-platform/ydb/pull/21918) for a new kind of change record in asynchronous replication — `reset` record (in addition to `update` & `erase` records). * [Fixed](https://github.com/ydb-platform/ydb/pull/21836) an [issue](https://github.com/ydb-platform/ydb/issues/21814) where a replication instance with an unspecified `COMMIT_INTERVAL` option caused the process to crash. * [Fixed](https://github.com/ydb-platform/ydb/pull/21652) rare errors when reading from a topic during partition balancing. * [Fixed](https://github.com/ydb-platform/ydb/pull/22455) an [issue](https://github.com/ydb-platform/ydb/issues/19842) where dedicated database deletion might leave database system tablets improperly cleaned. * [Fixed](https://github.com/ydb-platform/ydb/pull/22203) an [issue](https://github.com/ydb-platform/ydb/issues/22030) that caused tablets to hang when nodes experienced critical memory shortage. Now tablets will automatically start as soon as any of the nodes frees up sufficient resources. * [Fixed](https://github.com/ydb-platform/ydb/pull/24278) an issue where only the first message from a batch was saved when writing Kafka messages, with all other messages in the batch being ignored. ### Release candidate 25.1.2.7 {#25-1-2-7-rc} Release date: July 14, 2025. #### Functionality * [Implemented](https://github.com/ydb-platform/ydb/issues/19504) a [vector index](https://ydb.tech/docs/en/dev/vector-indexes.md?version=v25.1) for approximate vector similarity search. * [Added](https://github.com/ydb-platform/ydb/issues/11454) support for [consistent asynchronous replication](https://ydb.tech/docs/en/concepts/async-replication.md?version=v25.1). * Added [configuration mechanism V2](./devops/configuration-management/configuration-v2/config-overview?version=v25.1) that simplifies the deployment of new YDB clusters and further work with them. [Comparison](./devops/configuration-management/compare-configs?version=v25.1) of configuration mechanisms V1 and V2. * Added support for the parameterized [Decimal type](https://ydb.tech/docs/en/yql/reference/types/primitive.md?version=v25.1#numeric). * [Added](https://github.com/ydb-platform/ydb/pull/8065) the ability to omit the `DECLARE` operator for query parameter type declarations. Parameter types are now automatically inferred from the provided values. * [Implemented](https://github.com/ydb-platform/ydb/issues/18017) client balancing of partitions when reading using the [Kafka protocol](https://kafka.apache.org/documentation/#consumerconfigs_partition.assignment.strategy) (like Kafka itself). Previously, balancing took place on the server. This mode is enabled by setting the `enable_kafka_native_balancing` flag in the cluster configuration. * Added support for [auto-partitioning topics](https://ydb.tech/docs/en/concepts/cdc.md?version=v25.1#topic-partitions) for row-oriented tables in CDC. This mode is enabled by setting the `enable_topic_autopartitioning_for_cdc` flag in the cluster configuration. * [Added](https://github.com/ydb-platform/ydb/pull/8264) the ability to [alter the retention period of CDC topics](https://ydb.tech/docs/en/concepts/cdc.md?version=v25.1#topic-settings) using the `ALTER TOPIC` statement. * [Added support](https://github.com/ydb-platform/ydb/pull/7052) for [the DEBEZIUM_JSON format](https://ydb.tech/docs/en/concepts/cdc.md?version=v25.1#debezium-json-record-structure) for CDC. * [Added](https://github.com/ydb-platform/ydb/pull/19507) the ability to create changefeed streams to index tables. * [Added](https://github.com/ydb-platform/ydb/issues/19310) the ability to [enable followers (read replicas)](https://ydb.tech/docs/en/yql/reference/syntax/alter_table/indexes.md?version=v25.1) for covered secondary indexes. This mode is enabled by setting the `enable_access_to_index_impl_tables` flag in the cluster configuration. * The scope of supported objects in backup and restore operations has been expanded: * [Support for changefeeds](https://github.com/ydb-platform/ydb/issues/7054) (enabled with the `enable_changefeeds_export` and `enable_changefeeds_import` flags). * [Support for views](https://github.com/ydb-platform/ydb/issues/12724) (enabled with the `enable_view_export` flag). * [Added](https://github.com/ydb-platform/ydb/issues/17734) automatic cleanup of temporary tables and directories during export to S3. This mode is enabled by setting the `enable_export_auto_dropping` flag in the cluster configuration. * [Added](https://github.com/ydb-platform/ydb/pull/12909) automatic integrity checks of backups during import, which prevent restoration from corrupted backups and protect against data loss. * [Added](https://github.com/ydb-platform/ydb/pull/15570) the ability to create views that refer to [UDFs](./yql/reference/builtins/basic?version=v25.1#udf) in queries. * Added system views with information about [access right settings](https://ydb.tech/docs/en/dev/system-views.md?version=v25.1#auth), [history of overloaded partitions](https://ydb.tech/docs/en/dev/system-views.md?version=v25.1#top-overload-partitions) - enabled by setting the `enable_followers_stats` flag in the cluster configuration, [history of partitions with broken locks](./dev/system-views?version=v25.1#top-tli-partitions). * Added new parameters to the [CREATE USER](https://ydb.tech/docs/en/yql/reference/syntax/create-user.md?version=v25.1) and [ALTER USER](https://ydb.tech/docs/en/yql/reference/syntax/alter-user.md?version=v25.1) operators: * `HASH` — sets a password in encrypted form. * `LOGIN` and `NOLOGIN` — unlocks and blocks a user, respectively. * Enhanced account security: * [Added](https://github.com/ydb-platform/ydb/pull/11963) user [password complexity](./reference/configuration/?version=v25.1#password-complexity) verification. * [Implemented](https://github.com/ydb-platform/ydb/pull/12578) [automatic user lockout](./reference/configuration/?version=v25.1#account-lockout) after a specified number of failed attempts to enter the correct password. * [Added](https://github.com/ydb-platform/ydb/pull/12983) the ability for users to change their own passwords. * [Implemented](https://github.com/ydb-platform/ydb/issues/9748) the ability to toggle functional flags at runtime. Changes to flags that do not specify `(RequireRestart) = true` in the [proto file](https://github.com/ydb-platform/ydb/blob/main/ydb/core/protos/feature_flags.proto#L60) are applied without a cluster restart. * [Changed](https://github.com/ydb-platform/ydb/pull/11329) lock behavior when shard locks exceed the limit. Once the limit is exceeded, the oldest locks (rather than the newest) are converted into full-shard locks. * [Implemented](https://github.com/ydb-platform/ydb/pull/12567) a mechanism to preserve optimistic locks in memory during graceful datashard restarts, reducing `ABORTED` errors caused by lock loss during table balancing. * [Implemented](https://github.com/ydb-platform/ydb/pull/12689) a mechanism to abort volatile transactions with the `ABORTED` status during graceful datashard restarts. * [Added](https://github.com/ydb-platform/ydb/pull/6342) support for removing `NOT NULL` constraints from a table column using the `ALTER TABLE ... ALTER COLUMN ... DROP NOT NULL` statement. * [Added](https://github.com/ydb-platform/ydb/pull/9168) a limit of 100,000 concurrent session-creation requests in the coordination service. * [Increased](https://github.com/ydb-platform/ydb/pull/14219) the maximum number of columns in the primary key from 20 to 30. * Improved diagnostics and introspection of memory errors ([#10419](https://github.com/ydb-platform/ydb/pull/10419), [#11968](https://github.com/ydb-platform/ydb/pull/11968)). * **_(Experimental)_** [Added](https://github.com/ydb-platform/ydb/pull/14075) an experimental mode with strict access control checks. This mode is enabled by setting these flags: * `enable_strict_acl_check` – do not allow granting rights to non-existent users and delete users with permissions; * `enable_strict_user_management` – enables strict checks for local users (i.e. only the cluster or database administrator can administer local users); * `enable_database_admin` – add the role of database administrator; #### Backward Incompatible Changes * If you are using queries that access named expressions as tables using the AS_TABLE function, update [temporary over YDB](https://github.com/yandex/temporal-over-ydb) to version [v1.23.0-ydb-compat](https://github.com/yandex/temporal-over-ydb/releases/tag/v1.23.0-ydb-compat) before updating YDB to the current version to avoid errors in query execution. #### YDB UI * Query Editor was redesigned to [support partial results load](https://github.com/ydb-platform/ydb-embedded-ui/pull/1974) - it starts displaying results when receives a chunk from the server, doesn't have to wait until the query completion. This approach allows application developers to see query results faster. * [Security Improvement](https://github.com/ydb-platform/ydb-embedded-ui/pull/1967): controls that are could not be activated by current user due to lack of permissions are not displayed. Users won't click and experience Access Denied error. * [Added](https://github.com/ydb-platform/ydb-embedded-ui/pull/1981) search by tablet id on Tablets tab. * HotKeys help tab accessible by ⌘+K key is added. * Operations tab is added to Database page. Operations allow to list operations and cancel them. * Cluster dashboard redesign and make it collapsable. * JsonViewer: handle case sensitive search. * Added code snippets for YDB SDK to connect to selected database. Such snippets must speed up development. * Rows on Queries tab were sorted by string values after proper backend sort. * QueryEditor: removed extra confirmation requests on leaving browser page – do not ask confirmation when it's irrelevant. #### Performance * [Added](https://github.com/ydb-platform/ydb/pull/6509) support for [constant folding](https://en.wikipedia.org/wiki/Constant_folding) in the query optimizer by default. This feature enhances query performance by evaluating constant expressions at compile time, thereby reducing runtime overhead and enabling faster, more efficient execution of complex static expressions. * [Added](https://github.com/ydb-platform/ydb/issues/6512) a granular timecast protocol for distributed transactions, ensuring that slowing one shard does not affect the performance of others. * [Implemented](https://github.com/ydb-platform/ydb/issues/11561) in-memory state migration on a graceful restart, preserving locks and improving transaction success rates. This reduces the execution time of long transactions by decreasing the number of retries. * [Implemented](https://github.com/ydb-platform/ydb/issues/15255) pipeline processing of internal transactions in Node Broker, accelerating the startup of dynamic nodes in the cluster. * [Improved](https://github.com/ydb-platform/ydb/pull/15607) Node Broker resilience under increased cluster load. * [Enabled](https://github.com/ydb-platform/ydb/pull/19440) evictable B-Tree indexes by default instead of non-evictable SST indexes, reducing memory consumption when storing cold data. * [Optimized](https://github.com/ydb-platform/ydb/pull/15264) memory consumption by storage nodes. * [Reduced](https://github.com/ydb-platform/ydb/pull/10969) Hive startup times to 30%. * [Optimized](https://github.com/ydb-platform/ydb/pull/6561) the distributed storage replication process. * [Optimized](https://github.com/ydb-platform/ydb/pull/9491) the header size of large binary objects in VDisk. * [Reduced](https://github.com/ydb-platform/ydb/pull/15517) memory consumption through allocator page cleaning. #### Bug Fixes * [Fixed](https://github.com/ydb-platform/ydb/pull/9707) an error in the [Interconnect](../concepts/glossary?version=v25.1#actor-system-interconnect) configuration that caused performance degradation. * [Fixed](https://github.com/ydb-platform/ydb/pull/13993) an out-of-memory error that occurred when deleting very large tables by limiting the number of tablets that process this operation concurrently. * [Fixed](https://github.com/ydb-platform/ydb/pull/9848) an issue that caused accidental duplicate entries in the system tablet configuration. * [Fixed](https://github.com/ydb-platform/ydb/pull/11059) an issue where data reads took too long (seconds) during frequent table resharding operations. * [Fixed](https://github.com/ydb-platform/ydb/pull/9723) an error reading from asynchronous replicas that caused failures. * [Fixed](https://github.com/ydb-platform/ydb/pull/9507) an issue that caused rare [CDC](https://ydb.tech/docs/en/dev/cdc.md?version=v25.1) initial scan freezes. * [Fixed](https://github.com/ydb-platform/ydb/pull/11483) an issue handling incomplete schema transactions in datashards during system restart. * [Fixed](https://github.com/ydb-platform/ydb/pull/10460) an issue causing inconsistent reads from a topic when explicitly confirming a message read within a transaction; users now receive an error when attempting to confirm a message. * [Fixed](https://github.com/ydb-platform/ydb/pull/12220) an issue in which topic auto-partitioning functioned incorrectly within a transaction. * [Fixed](https://github.com/ydb-platform/ydb/pull/12905) an issue in which transactions hang when working with topics during tablet restarts. * [Fixed](https://github.com/ydb-platform/ydb/pull/13910) the "Key is out of range" error when importing data from S3-compatible storage. * [Fixed](https://github.com/ydb-platform/ydb/pull/13741) an issue in which the end of the metadata field in the cluster configuration. * [Improved](https://github.com/ydb-platform/ydb/pull/16420) the secondary index build process: the system now retries on certain errors instead of interrupting the build. * [Fixed](https://github.com/ydb-platform/ydb/pull/16635) an error executing the `RETURNING` expression in `INSERT` and `UPSERT` operations. * [Fixed](https://github.com/ydb-platform/ydb/pull/16269) an issue causing Drop Tablet operations in PQ tablets to hang during Interconnect delays. * [Fixed](https://github.com/ydb-platform/ydb/pull/16194) an error during VDisk [compaction](../concepts/glossary?version=v25.1#compaction). * [Fixed](https://github.com/ydb-platform/ydb/pull/15233) an issue in which long topic-reading sessions ended with "too big inflight" errors. * [Fixed](https://github.com/ydb-platform/ydb/pull/15515) an issue where reading a topic by multiple consumers hangs if at least one partition has no incoming data. * [Fixed](https://github.com/ydb-platform/ydb/pull/18614) a rare issue with PQ tablet restarts. * [Fixed](https://github.com/ydb-platform/ydb/pull/18378) an issue in which, after updating the cluster version, Hive started subscribers in data centers without running database nodes. * [Fixed](https://github.com/ydb-platform/ydb/pull/19057) an issue in which the `Failed to set up listener on port 9092 errno# 98 (Address already in use)` error occurred during version updates. * [Fixed](https://github.com/ydb-platform/ydb/pull/18905) an error that led to a segmentation fault when a healthcheck request and a cluster-node disable request executed simultaneously. * [Fixed](https://github.com/ydb-platform/ydb/pull/18899) an issue that caused partitioning of [row-oriented tables](https://ydb.tech/docs/en/concepts/datamodel/table.md?version=v25.1#partitioning_row_table) to fail when a split key was selected from access samples containing a mix of full-key and key-prefix operations (such as exact and range reads). * [Fixed](https://github.com/ydb-platform/ydb/pull/18647) an [issue](https://github.com/ydb-platform/ydb/issues/17885) where the index type defaulted to `GLOBAL SYNC` despite `UNIQUE` being explicitly specified. * [Fixed](https://github.com/ydb-platform/ydb/pull/16797) an issue where topic auto-partitioning did not work when the `max_active_partition` parameter was set via `ALTER TOPIC`. * [Fixed](https://github.com/ydb-platform/ydb/pull/18938) an issue that caused `db scheme describe` to return columns out of their original creation order. ## Version 24.4 {#24-4} ### Version 24.4.4.12 {#24-4-4-12} Release date: June 3, 2025. ## Performance * [Limited](https://github.com/ydb-platform/ydb/pull/17755) the number of internal inflight configuration updates. * [Optimized](https://github.com/ydb-platform/ydb/issues/18289) memory consumption by PQ tablets. * [Optimized](https://github.com/ydb-platform/ydb/issues/18473) CPU consumption of Scheme shard and reduced query latencies by checking operation count limits before performing tablet split and merge operations. ## Bug Fixes * [Fixed](https://github.com/ydb-platform/ydb/pull/17123) a rare issue of client applications hanging during transaction commit where deleting partition had been done before write quota update. * [Fixed](https://github.com/ydb-platform/ydb/pull/17312) an error in copying tables with Decimal type, which caused failures when rolling back to a previous version. * [Fixed](https://github.com/ydb-platform/ydb/pull/17519) an [issue](https://github.com/ydb-platform/ydb/issues/17499) where a commit without confirmation of writing to a topic led to the blocking of the current and subsequent transactions with topics. * Fixed transaction hanging when working with topics during tablet [restart](https://github.com/ydb-platform/ydb/issues/17843) or [deletion](https://github.com/ydb-platform/ydb/issues/17915). * [Fixed](https://github.com/ydb-platform/ydb/pull/18114) [issues](https://github.com/ydb-platform/ydb/issues/18071) with reading messages larger than 6Mb via [Kafka API](./reference/kafka-api). * [Fixed](https://github.com/ydb-platform/ydb/pull/18319) memory leak during writing to the [topic](./concepts/glossary#topic). * Fixed errors in processing [nullable columns](https://github.com/ydb-platform/ydb/issues/15701) and [columns with UUID type](https://github.com/ydb-platform/ydb/issues/15697) in row tables. ### Version 24.4.4.2 {#24-4-4-2} Release date: April 15, 2025 #### Functionality * Enabled by default: * support for [views](https://ydb.tech/docs/en/concepts/datamodel/view.md) * [auto-partitioning mode](https://ydb.tech/docs/en/concepts/datamodel/topic.md#autopartitioning) for topics * [transactions involving topics and row-oriented tables simultaneously](https://ydb.tech/docs/en/concepts/transactions.md#topic-table-transactions) * [volatile distributed transactions](https://ydb.tech/docs/en/contributor/datashard-distributed-txs.md#volatile-transactions) * Added the ability to [read and write to a topic](https://ydb.tech/docs/en/reference/kafka-api/examples.md#kafka-api-usage-examples) using the Kafka API without authentication. #### Performance * Enabled by default automatic secondary index selection for queries. #### Bug Fixes * [Fixed](https://github.com/ydb-platform/ydb/pull/14811) an error that led to a significant decrease in reading speed from [tablet followers](https://ydb.tech/docs/en/concepts/glossary.md#tablet-follower). * [Fixed](https://github.com/ydb-platform/ydb/pull/14516) an error that caused volatile distributed transactions to sometimes wait for confirmations until the next reboot. * [Fixed](https://github.com/ydb-platform/ydb/pull/15077) a rare assertion failure (server process crash) when followers attached to leaders with an inconsistent snapshot. * [Fixed](https://github.com/ydb-platform/ydb/pull/15074) a rare datashard crash when a dropped table shard is restarted with uncommitted persistent changes. * [Fixed](https://github.com/ydb-platform/ydb/pull/15194) an error that could disrupt the order of message processing in a topic. * [Fixed](https://github.com/ydb-platform/ydb/pull/15308) a rare error that could stop reading from a topic partition. * [Fixed](https://github.com/ydb-platform/ydb/pull/15160) an issue where a transaction could hang if a user performed a control plane operation on a topic (for example, adding partitions or a consumer) while the PQ tablet is moving to another node. * [Fixed](https://github.com/ydb-platform/ydb/pull/15233) a memory leak issue with the UserInfo counter value. Because of the memory leak, a reading session would eventually return a "too big in flight" error. * [Fixed](https://github.com/ydb-platform/ydb/pull/15467) a proxy crash due to duplicate topics in a request. * [Fixed](https://github.com/ydb-platform/ydb/pull/15933) a rare bug where a user could write to a topic without any account quota being applied or consumed. * [Fixed](https://github.com/ydb-platform/ydb/pull/16288) an issue where topic deletion returned "OK" while the topic tablets persisted in a functional state. To remove such tablets, follow the instructions from the [pull request](https://github.com/ydb-platform/ydb/pull/16288). * [Fixed](https://github.com/ydb-platform/ydb/pull/16418) a rare issue that prevented the restoration of a backup for a large secondary indexed table. * [Fixed](https://github.com/ydb-platform/ydb/pull/15862) an issue that caused errors when inserting data using `UPSERT` into row-oriented tables with default values. * [Resolved](https://github.com/ydb-platform/ydb/pull/15334) a bug that caused failures when executing queries to tables with secondary indexes that returned result lists using the RETURNING * expression. ## Version 24.3 {#24-3} ### Version 24.3.15.5 {#24-3-15-5} Release date: February 6, 2025 #### Functionality * Added the ability to register a [database node](https://ydb.tech/docs/en/concepts/glossary.md#database-node) using a certificate. In the [Node Broker](https://ydb.tech/docs/en/concepts/glossary.md#node-broker) the flag `AuthorizeByCertificate` has been added to enable certificate-based registration. * [Added](https://github.com/ydb-platform/ydb/pull/11775) priorities for authentication ticket through a [third-party IAM provider](https://ydb.tech/docs/en/security/authentication.md#iam), with the highest priority given to requests from new users. Tickets in the cache update their information with a lower priority. #### Performance * [Improved](https://github.com/ydb-platform/ydb/pull/12747) tablet startup time on large clusters: 210 ms → 125 ms (SSD), 260 ms → 165 ms (HDD). #### Bug Fixes * [Removed](https://github.com/ydb-platform/ydb/pull/11901) the restriction on writing values greater than 127 to the Uint8 type. * [Fixed](https://github.com/ydb-platform/ydb/pull/12221) an issue where reading small messages from a topic in small chunks significantly increased CPU load, which could lead to delays in reading and writing to the topic. * [Fixed](https://github.com/ydb-platform/ydb/pull/12915) an issue with restoring from a backup stored in S3 with path-style addressing. * [Fixed](https://github.com/ydb-platform/ydb/pull/13222) an issue with restoring from a backup that was created during an automatic table split. * [Fixed](https://github.com/ydb-platform/ydb/pull/12601) an issue with Uuid serialization for [CDC](https://ydb.tech/docs/en/concepts/cdc.md). * [Fixed](https://github.com/ydb-platform/ydb/pull/12018) an issue with ["frozen" locks](https://ydb.tech/docs/en/contributor/datashard-locks-and-change-visibility.md#interaction-with-distributed-transactions), which could be caused by bulk operations (e.g., TTL-based deletions). * [Fixed](https://github.com/ydb-platform/ydb/pull/12804) an issue where reading from a follower of tablets sometimes caused crashes during automatic table splits. * [Fixed](https://github.com/ydb-platform/ydb/pull/12807) an issue where the [coordination node](https://ydb.tech/docs/en/concepts/datamodel/coordination-node.md) successfully registered proxy servers despite a connection loss. * [Fixed](https://github.com/ydb-platform/ydb/pull/11593) an issue that occurred when opening the Embedded UI tab with information about [distributed storage groups](https://ydb.tech/docs/en/concepts/glossary.md#storage-group). * [Fixed](https://github.com/ydb-platform/ydb/pull/12448) an issue where the Health Check did not report time synchronization issues. * [Fixed](https://github.com/ydb-platform/ydb/pull/11658) a rare issue that caused errors during read queries. * [Fixed](https://github.com/ydb-platform/ydb/pull/13501) an uncommitted changes leak and cleaned them up on startup. * [Fixed](https://github.com/ydb-platform/ydb/pull/13948) consistency issues related to caching deleted ranges. ### Version 24.3.11.14 {#24-3-11-14} Release date: January 9, 2025. #### Functionality * [Added](https://github.com/ydb-platform/ydb/pull/13251) support for restart without downtime in [a minimal fault-tolerant configuration of a cluster](https://ydb.tech/docs/en/concepts/topology.md#reduced) that uses the three-node variant of `mirror-3-dc`. * [Added](https://github.com/ydb-platform/ydb/pull/13220) new UDF Roaring Bitmap functions: AndNotWithBinary, FromUint32List, RunOptimize. ### Version 24.3.11.13 {#24-3-11-13} Release date: December 24, 2024. #### Functionality * Introduced [query tracing](./reference/observability/tracing/setup), a tool that allows you to view the detailed path of a request through a distributed system. * Added support for [asynchronous replication](./concepts/async-replication), that allows synchronizing data between YDB databases in near real time. It can also be used for data migration between databases with minimal downtime for applications interacting with these databases. * Added support for [views](./concepts/datamodel/view), which can be enabled by the cluster administrator using the `enable_views` setting in [dynamic configuration](./maintenance/manual/dynamic-config#updating-dynamic-configuration). * Extended [federated query](./concepts/query_execution/federated_query/) capabilities to support new external data sources: MySQL, Microsoft SQL Server, and Greenplum. * Published [documentation](https://ydb.tech/docs/en/devops/deployment-options/manual/federated-queries/connector-deployment.md) on deploying YDB with [federated query](./concepts/query_execution/federated_query/) functionality (manual setup). * Added a new launch parameter `FQ_CONNECTOR_ENDPOINT` for YDB Docker containers that specifies an external data source connector address. Added support for TLS encryption for connections to the connector and the ability to expose the connector service port locally on the same host as the dynamic YDB node. * Added an [auto-partitioning mode](https://ydb.tech/docs/en/concepts/datamodel/topic.md#autopartitioning) for topics, where partitions can dynamically split based on load while preserving message read-order and exactly-once guarantees. The mode can be enabled by the cluster administrator using the settings `enable_topic_split_merge` and `enable_pqconfig_transactions_at_scheme_shard` in [dynamic configuration](./maintenance/manual/dynamic-config#updating-dynamic-configuration). * Added support for transactions involving [topics](./concepts/topic) and row-based tables, enabling transactional data transfer between tables and topics, or between topics, ensuring no data loss or duplication. Transactions can be enabled by the cluster administrator using the settings `enable_topic_service_tx` and `enable_pqconfig_transactions_at_scheme_shard` in [dynamic configuration](./maintenance/manual/dynamic-config#updating-dynamic-configuration). * [Implemented](https://github.com/ydb-platform/ydb/pull/7150) [Change Data Capture (CDC)](./concepts/cdc) for synchronous secondary indexes. * Added support for changing record retention periods in [CDC](./concepts/cdc) topics. * Added support for auto-increment columns as part of a table's primary key. * Added audit logging for user login events in YDB, session termination events in the user interface, and backup/restore operations. * Added a system view with information about sessions installed from the database using a query. * Added support literal default values for row-oriented tables. When inserting a new row in YDB Query default values will be assigned to the column if specified. * Added the `version()` [built-in function](https://ydb.tech/docs/en/yql/reference/builtins/basic.md#version). * Added support for `RETURNING` clause in queries. * [Added](https://github.com/ydb-platform/ydb/pull/8708) start/end times and authors in the metadata for backup/restore operations from S3-compatible storage. * Added support for backup/restore of ACL for tables from/to S3-compatible storage. * Included paths and decompression methods in query plans for reading from S3. * Added new parsing options for timestamp/datetime fields when reading data from S3. * Added support for the `Decimal` type in [partitioning keys](./dev/primary-key/column-oriented#klyuch-particionirovaniya). * Improved diagnostics for storage issues in HealthCheck. * **_(Experimental)_** Added a [cost-based optimizer](./concepts/optimizer#cost-based-query-optimizer) for complex queries, involving [column-oriented tables](./concepts/glossary#column-oriented-table). The cost-based optimizer considers a large number of alternative execution plans for each query and selects the best one based on the cost estimate for each option. Currently, this optimizer only works with plans that contain [JOIN](./yql/reference/syntax/join) operations. * **_(Experimental)_** Initial version of the workload manager was implemented. It allows to create resource pools with CPU, memory and active queries count limits. Resource classifiers were implemented to assign queries to specific resource pool. * **_(Experimental)_** Implemented [automatic index selection](./dev/secondary-indexes#avtomaticheskoe-ispolzovanie-indeksov-pri-vyborke) for queries, which can be enabled via the `index_auto_choose_mode setting` in `table_service_config` in [dynamic configuration](./maintenance/manual/dynamic-config#updating-dynamic-configuration). #### YDB UI * Added support for creating and [viewing information on](https://github.com/ydb-platform/ydb-embedded-ui/issues/782) asynchronous replication instances. * [Added](https://github.com/ydb-platform/ydb-embedded-ui/issues/929) an indicator for auto-increment columns. * [Added](https://github.com/ydb-platform/ydb-embedded-ui/pull/1438) a tab with information about [tablets](./concepts/glossary#tablet). * [Added](https://github.com/ydb-platform/ydb-embedded-ui/pull/1289) a tab with details about [distributed storage groups](./concepts/glossary#storage-group). * [Added](https://github.com/ydb-platform/ydb-embedded-ui/pull/1218) a setting to trace all queries and display tracing results. * Enhanced the PDisk page with [attributes](https://github.com/ydb-platform/ydb-embedded-ui/pull/1069), disk space consumption details, and a button to initiate [disk decommissioning](https://ydb.tech/docs/en/devops/deployment-options/manual/decommissioning.md). * [Added](https://github.com/ydb-platform/ydb-embedded-ui/pull/1313) information about currently running queries. * [Added](https://github.com/ydb-platform/ydb-embedded-ui/pull/1291) a row limit setting for query editor output and a notification when results exceed the limit. * [Added](https://github.com/ydb-platform/ydb-embedded-ui/pull/1049) a tab to display top CPU-consuming queries over the last hour. * [Added](https://github.com/ydb-platform/ydb-embedded-ui/pull/1127) a control to search the history and saved queries pages. * [Added](https://github.com/ydb-platform/ydb-embedded-ui/pull/1117) the ability to cancel query execution. * [Added](https://github.com/ydb-platform/ydb-embedded-ui/issues/944) a shortcut to save queries in the editor. * [Separated](https://github.com/ydb-platform/ydb-embedded-ui/pull/1422) donor disks from other disks in the UI. * [Added](https://github.com/ydb-platform/ydb-embedded-ui/pull/1154) support for InterruptInheritance ACL and improved visualization of active ACLs. * [Added](https://github.com/ydb-platform/ydb-embedded-ui/pull/889) a display of the current UI version. * [Added](https://github.com/ydb-platform/ydb-embedded-ui/pull/1229) a tab with information about the status of settings for enabling experimental functionality. #### Performance * [Accelerated](https://github.com/ydb-platform/ydb/pull/7589) recovery of tables with secondary indexes from backups up to 20% according to our tests. * [Optimized](https://github.com/ydb-platform/ydb/pull/9721) Interconnect throughput. * Improved the performance of CDC topics with thousands of partitions. * Enhanced the Hive tablet balancing algorithm. #### Bug fixes * [Fixed](https://github.com/ydb-platform/ydb/pull/6850) an issue that caused databases with a large number of tables or partitions to become non-functional during restoration from a backup. Now, if database size limits are exceeded, the restoration operation will fail, but the database will remain operational. * [Implemented](https://github.com/ydb-platform/ydb/pull/11532) a mechanism to forcibly trigger background [compaction](./concepts/glossary#compaction) when discrepancies between the data schema and stored data are detected in [DataShard](./concepts/glossary#data-shard). This resolves a rare issue with delays in schema changes. * [Resolved](https://github.com/ydb-platform/ydb/pull/10447) duplication of authentication tickets, which led to an increased number of requests to authentication providers. * [Fixed](https://github.com/ydb-platform/ydb/pull/9377) an invariant violation issue during the initial scan of CDC, leading to an abnormal termination of the `ydbd` server process. * [Prohibited](https://github.com/ydb-platform/ydb/pull/9446) schema changes for backup tables. * [Fixed](https://github.com/ydb-platform/ydb/pull/9509) an issue with an initial scan freezing during CDC when the table is frequently updated. * [Excluded](https://github.com/ydb-platform/ydb/pull/9934) deleted indexes from the count against the [maximum index limit](./concepts/limits-ydb#schema-object). * Fixed a [bug](https://github.com/ydb-platform/ydb/issues/6985) in the display of the scheduled execution time for a set of transactions (planned step). * [Fixed](https://github.com/ydb-platform/ydb/pull/9161) a [problem](https://github.com/ydb-platform/ydb/issues/8942) with interruptions in blue–green deployment in large clusters caused by frequent updates to the node list. * [Resolved](https://github.com/ydb-platform/ydb/pull/8925) a rare issue that caused transaction order violations. * [Fixed](https://github.com/ydb-platform/ydb/pull/9841) an [issue](https://github.com/ydb-platform/ydb/issues/9797) in the EvWrite API that resulted in incorrect memory deallocation. * [Resolved](https://github.com/ydb-platform/ydb/pull/10698) a [problem](https://github.com/ydb-platform/ydb/issues/10674) with volatile transactions hanging after a restart. * Fixed a bug in the CDC, which in some cases leads to increased CPU consumption, up to a core per CDC partition. * [Eliminated](https://github.com/ydb-platform/ydb/pull/11061) read delays occurring during and after the splitting of certain partitions. * Fixed issues when reading data from S3. * [Corrected](https://github.com/ydb-platform/ydb/pull/4793) the calculation of the AWS signature for S3 requests. * Resolved false positives in the HealthCheck system during database backups involving a large number of shards. ## Version 24.2 {#24-2} Release date: August 20, 2024. ### Functionality * Added the ability to set [maintenance task priorities](https://ydb.tech/docs/en/devops/concepts/maintenance-without-downtime.md#priority) in the [cluster management system](https://ydb.tech/docs/en/concepts/glossary.md#cms). * Added a setting to enable [stable names](./reference/configuration/#node-broker-config) for cluster nodes within a tenant. * Enabled retrieval of nested groups from the [LDAP server](./concepts/auth#ldap-auth-provider), improved host parsing in the [LDAP-configuration](./reference/configuration/#ldap-auth-config), and added an option to disable built-in authentication via login and password. * Added support for authenticating [dynamic nodes](./concepts/glossary#dynamic) using SSL-certificates. * Implemented the removal of inactive nodes from [Hive](./concepts/glossary#hive) without a restart. * Improved management of inflight pings during Hive restarts in large clusters. * Changed the order of establishing connections with nodes during Hive restarts. ### YDB UI * [Added](https://github.com/ydb-platform/ydb/pull/7485) the option to set a TTL for user sessions in the configuration file. * [Added](https://github.com/ydb-platform/ydb-embedded-ui/issues/996) an option to sort the list of queries by `CPUTime`. * [Fixed](https://github.com/ydb-platform/ydb/pull/7779) precision loss when working with `double`, `float` data types. * [Added support](https://github.com/ydb-platform/ydb-embedded-ui/pull/958) for creating directories in the UI. * [Added](https://github.com/ydb-platform/ydb-embedded-ui/pull/976) an auto-refresh control on all pages. * [Improved](https://github.com/ydb-platform/ydb-embedded-ui/pull/955) ACL display. * Enabled autocomplete in the queries editor by default. * Added support for views. ### Bug fixes * Added a check on the size of the local transaction prior to its commit to fix [errors](https://github.com/db-platform/ydb/issues/6677) in scheme shard operations when exporting/backing up large databases. * [Fixed](https://github.com/ydb-platform/ydb/pull/7709) an issue with duplicate results in SELECT queries when reducing quotas in [DataShard](./concepts/glossary#data-shard). * [Fixed](https://github.com/ydb-platform/ydb/pull/6461) [errors](https://github.com/ydb-platform/ydb/issues/6220) occurring during [coordinator](./concepts/glossary#coordinator) state changes. * [Fixed](https://github.com/ydb-platform/ydb/pull/5992) issues during the initial CDC scan. * [Resolved](https://github.com/ydb-platform/ydb/pull/6615) race conditions in asynchronous change delivery (asynchronous indexes, CDC). * [Fixed](https://github.com/ydb-platform/ydb/pull/5993) a crash that sometimes occurred during [TTL-based](./concepts/ttl) deletions. * [Fixed](https://github.com/ydb-platform/ydb/pull/5760) an issue with PDisk status display in the [CMS](./concepts/glossary#cms). * [Fixed](https://github.com/ydb-platform/ydb/pull/6008) an issue that might cause soft tablet transfers (drain) from a node to hang. * [Resolved](https://github.com/ydb-platform/ydb/pull/6445) an issue with the interconnect proxy stopping on a node that is running without restarts. The issue occurred when adding another node to the cluster. * [Corrected](https://github.com/ydb-platform/ydb/pull/7023) string escaping in error messages. * [Fixed](https://github.com/ydb-platform/ydb/pull/6695) an issue with managing free memory in the [interconnect](./concepts/glossary#actor-system-interconnect). * [Corrected](https://github.com/ydb-platform/ydb/issues/6405) UnreplicatedPhantoms and UnreplicatedNonPhantoms counters in VDisk. * [Fixed](https://github.com/ydb-platform/ydb/issues/6398) an issue with handling empty garbage collection requests on VDisk. * [Resolved](https://github.com/ydb-platform/ydb/pull/5894) issues with managing TVDiskControls settings through CMS. * [Fixed](https://github.com/ydb-platform/ydb/pull/5883) an issue with failing to load the data created by newer versions of VDisk. * [Fixed](https://github.com/ydb-platform/ydb/pull/5862) an issue with executing the `REPLACE INTO` queries with default values. * [Fixed](https://github.com/ydb-platform/ydb/pull/7714) errors in queries with multiple LEFT JOINs to a single string table. * [Fixed](https://github.com/ydb-platform/ydb/pull/7740) precision loss for `float`,`double` types when using CDC. ## Version 24.1 {#24-1} Release date: July 31, 2024. ### Functionality * The [Knn UDF](https://ydb.tech/docs/en/yql/reference/udf/list/knn.md) function for precise nearest vector search has been implemented. * The gRPC Query service has been developed, enabling the execution of all types of queries (DML, DDL) and retrieval of unlimited amounts of data. * [Integration with the LDAP protocol](https://ydb.tech/docs/en/security/authentication.md) has been implemented, allowing the retrieval of a list of groups from external LDAP directories. ### Embedded UI * The database information tab now includes a resource consumption diagnostic dashboard, which allows users to assess the current consumption of key resources: processor cores, RAM, and distributed storage space. * Charts for monitoring the key performance indicators of the YDB cluster have been added. ### Performance * [Session timeouts](https://github.com/ydb-platform/ydb/pull/1837) for the coordination service between server and client have been optimized. Previously, the timeout was 5 seconds, which could result in a 10-second delay in identifying an unresponsive client and releasing its resources. In the new version, the check interval depends on the session's wait time, allowing for faster responses during leader changes or when acquiring distributed locks. * CPU consumption by [SchemeShard](https://ydb.tech/docs/en/concepts/glossary.md#scheme-shard) replicas has been [optimized](https://github.com/ydb-platform/ydb/pull/2391), particularly when handling rapid updates for tables with a large number of partitions. ### Bug fixes * A possible queue overflow error has been [fixed](https://github.com/ydb-platform/ydb/pull/3917). [Change Data Capture](https://ydb.tech/docs/en/dev/cdc.md) now reserves the change queue capacity during the initial scan. * A potential deadlock between receiving and sending CDC records has been [fixed](https://github.com/ydb-platform/ydb/pull/4597). * An issue causing the loss of the mediator task queue during mediator reconnection has been [fixed](https://github.com/ydb-platform/ydb/pull/2056). This fix allows processing of the mediator task queue during resynchronization. * A rarely occurring error has been [fixed](https://github.com/ydb-platform/ydb/pull/2624), where with volatile transactions enabled, a successful transaction confirmation result could be returned before the transaction was fully committed. Volatile transactions remain disabled by default and are still under development. * A rare error that led to the loss of established locks and the successful confirmation of transactions that should have failed with a "Transaction Locks Invalidated" error has been [fixed](https://github.com/ydb-platform/ydb/pull/2839). * A rare error that could result in a violation of data integrity guarantees during concurrent read and write operations on a specific key has been [fixed](https://github.com/ydb-platform/ydb/pull/3074). * An issue causing read replicas to stop processing requests has been [fixed](https://github.com/ydb-platform/ydb/pull/4343). * A rare error that could cause abnormal termination of database processes if there were uncommitted transactions on a table during its renaming has been [fixed](https://github.com/ydb-platform/ydb/pull/4979). * An error in determining the status of a static group, where it was not marked as non-working when it should have been, has been [fixed](https://github.com/ydb-platform/ydb/pull/3632). * An error involving partial commits of a distributed transaction with uncommitted changes, caused by certain race conditions with restarts, has been [fixed](https://github.com/ydb-platform/ydb/pull/2169). * Anomalies related to reading outdated data, [detected using Jepsen](https://blog.ydb.tech/hardening-ydb-with-jepsen-lessons-learned-e3238a7ef4f2), have been [fixed](https://github.com/ydb-platform/ydb/pull/2374). ## Version 23.4 {#23-4} Release date: May 14, 2024. ### Performance * [Fixed](https://github.com/ydb-platform/ydb/pull/3638) an issue of increased CPU consumption by a topic actor `PERSQUEUE_PARTITION_ACTOR`. * [Optimized](https://github.com/ydb-platform/ydb/pull/2083) resource usage by SchemeBoard replicas. The greatest effect is noticeable when modifying the metadata of tables with a large number of partitions. ### Bug fixes * [Fixed a bug](https://github.com/ydb-platform/ydb/pull/2169) of possible partial commit of accumulated changes when using persistent distributed transactions. This error occurs in an extremely rare combination of events, including restarting tablets that service the table partitions involved in the transaction. * [Fixed a bug](https://github.com/ydb-platform/ydb/pull/3165) involving a race condition between the table merge and garbage collection processes, which could result in garbage collection ending with an invariant violation error, leading to an abnormal termination of the `ydbd` server process. * [Fixed a bug](https://github.com/ydb-platform/ydb/pull/2696) in Blob Storage, where information about changes to the composition of a storage group might not be received in a timely manner by individual cluster nodes. As a result, reads and writes of data stored in the affected group could become blocked in rare cases, requiring manual intervention. * [Fixed a bug](https://github.com/ydb-platform/ydb/pull/3002) in Blob Storage, where data storage nodes might not start despite the correct configuration. The error occurred on systems with the experimental "blob depot" feature explicitly enabled (this feature is disabled by default). * [Fixed a bug](https://github.com/ydb-platform/ydb/pull/2475) that sometimes occurred when writing to a topic with an empty `producer_id` with turned off deduplication. It could lead to abnormal termination of the `ydbd` server process. * [Fixed a bug](https://github.com/ydb-platform/ydb/pull/2651) that caused the `ydbd` process to crash due to an incorrect session state when writing to a topic. * [Fixed a bug](https://github.com/ydb-platform/ydb/pull/3587) in displaying the metric of number of partitions in a topic, where it previously displayed an incorrect value. * [Fixed a bug](https://github.com/ydb-platform/ydb/pull/2126) causing memory leaks that appeared when copying topic data between clusters. These could cause `ydbd` server processes to terminate due to out-of-memory issues. ## Version 23.3 {#23-3} Release date: October 12, 2023. ### Functionality * Implemented visibility of own changes. With this feature enabled you can read changed values from the current transaction, which has not been committed yet. This functionality also allows multiple modifying operations in one transaction on a table with secondary indexes. * Added support for [column tables](https://ydb.tech/docs/en/concepts/datamodel/table.md#column-tables). It is now possible to create analytical reports based on stored data in YDB with performance comparable to specialized analytical DBMS. * Added support for Kafka API for topics. YDB topics can now be accessed via a Kafka-compatible API designed for migrating existing applications. Support for Kafka protocol version 3.4.0 is provided. * Added the ability to [write to a topic without deduplication](https://ydb.tech/docs/en/concepts/datamodel/topic.md#no-dedup). This is important in cases where message processing order is not critical. * YQL has added the capabilities to [create](https://ydb.tech/docs/en/yql/reference/syntax/create-topic.md), [modify](https://ydb.tech/docs/en/yql/reference/syntax/alter-topic.md), and [delete](https://ydb.tech/docs/en/yql/reference/syntax/delete.md) topics. * Added support of assigning and revoking access rights using the YQL `GRANT` and `REVOKE` commands. * Added support of DML-operations logging in the audit log. * **_(Experimental)_** When writing messages to a topic, it is now possible to pass metadata. To enable this functionality, add `enable_topic_message_meta: true` to the [configuration file](https://ydb.tech/docs/en/reference/configuration/index.md). * **_(Experimental)_** Added support for [reading from topics in a transaction](https://ydb.tech/docs/en/reference/ydb-sdk/topic.md#read-tx). It is now possible to read from topics and write to tables within a transaction, simplifying the data transfer scenario from a topic to a table. To enable this functionality, add `enable_topic_service_tx: true` to the [configuration file](https://ydb.tech/docs/en/reference/configuration/index.md). * **_(Experimental)_** Added support for PostgreSQL compatibility. This involves executing SQL queries in PostgreSQL dialect on the YDB infrastructure using the PostgreSQL network protocol. With this capability, familiar PostgreSQL tools such as psql and drivers (e.g., pq for Golang and psycopg2 for Python) can be used. Queries can be developed using the familiar PostgreSQL syntax and take advantage of YDB's benefits such as horizontal scalability and fault tolerance. * **_(Experimental)_** Added support for federated queries. This enables retrieving information from various data sources without the need to move the data into YDB. Federated queries support interaction with ClickHouse and PostgreSQL databases, as well as S3 class data stores (Object Storage). YQL queries can be used to access these databases without duplicating data between systems. ### Embedded UI * A new option `PostgreSQL` has been added to the query type selector settings, which is available when the `Enable additional query modes` parameter is enabled. Also, the query history now takes into account the syntax used when executing the query. * The YQL query template for creating a table has been updated. Added a description of the available parameters. * Now sorting and filtering for Storage and Nodes tables takes place on the server. To use this functionality, you need to enable the parameter `Offload tables filters and sorting to backend` in the experiments section. * Buttons for creating, changing and deleting [topics](https://ydb.tech/docs/en/concepts/datamodel/topic.md) have been added to the context menu. * Added sorting by criticality for all issues in the tree in `Healthcheck`. ### Performance * Implemented read iterators. This feature allows to separate reads and computations. Read iterators allow datashards to increase read queries throughput. * The performance of writing to YDB topics has been optimized. * Improved tablet balancing during node overload. ### Bug fixes * Fixed an error regarding potential blocking of reading iterators of snapshots, of which the coordinators were unaware. * Memory leak when closing the connection in Kafka proxy has been fixed. * Fixed an issue where snapshots taken through reading iterators may fail to recover on restarts. * Fixed an issue with an incorrect residual predicate for the `IS NULL` condition on a column. * Fixed an occurring verification error: `VERIFY failed: SendResult(): requirement ChunksLimiter.Take(sendBytes) failed`. * Fixed `ALTER TABLE` for TTL on column-based tables. * Implemented a `FeatureFlag` that allows enabling/disabling work with `CS` and `DS`. * Fixed a 50ms time difference between coordinator time in 23-2 and 23-3. * Fixed an error where the storage endpoint was returning extra groups when the `viewer backend` had the `node_id` parameter in the request. * Added a usage filter to the `/storage` endpoint in the `viewer backend`. * Fixed an issue in Storage v2 where an incorrect number was returned in the `Degraded field`. * Fixed an issue with cancelling subscriptions from sessions during tablet restarts. * Fixed an error where `healthcheck alerts` for storage were flickering during rolling restarts when going through a load balancer. * Updated `CPU usage metrics` in YDB. * Fixed an issue where `NULL` was being ignored when specifying `NOT NULL` in the table schema. * Implemented logging of `DDL` operations in the common log. * Implemented restriction for the YDB table attribute `add/drop` command to only work with tables and not with any other objects. * Disabled `CloseOnIdle` for interconnect. * Fixed the doubling of read speed in the UI. * Fixed an issue where data could be lost on block-4-2. * Added a check for topic name validity. * Fixed a possible deadlock in the actor system. * Fixed the `KqpScanArrowInChanels::AllTypesColumns` test. * Fixed the `KqpScan::SqlInParameter` test. * Fixed parallelism issues for OLAP queries. * Fixed the insertion of `ClickBench` parquet files. * Added a missing call to `CheckChangesQueueOverflow` in the general `CheckDataTxReject`. * Fixed an error that returned an empty status in `ReadRows` API calls. * Fixed incorrect retry behavior in the final stage of export. * Fixed an issue with infinite quota for the number of records in a `CDC topic`. * Fixed the import error of `string` and `parquet` columns into an `OLAP string column`. * Fixed a crash in `KqpOlapTypes.Timestamp` under `tsan`. * Fixed a `viewer backend` crash when attempting to execute a query against the database due to version incompatibility. * Fixed an error where the viewer did not return a response from the `healthcheck` due to a timeout. * Fixed an error where incorrect `ExpectedSerial` values could be saved in `Pdisks`. * Fixed an error where database nodes were crashing due to segfault in the S3 actor. * Fixed a race condition in `ThreadSanitizer: data race KqpService::ToDictCache-UseCache`. * Fixed a race condition in `GetNextReadId`. * Fixed an issue with an inflated result in `SELECT COUNT(*)` immediately after import. * Fixed an error where `TEvScan` could return an empty dataset in the case of shard splitting. * Added a separate `issue/error` code in case of available space exhaustion. * Fixed a `GRPC_LIBRARY Assertion` failed error. * Fixed an error where scanning queries on secondary indexes returned an empty result. * Fixed validation of `CommitOffset` in `TopicAPI`. * Reduced shared cache consumption when approaching OOM. * Merged scheduler logic from data executer and scan executer into one class. * Added discovery and `proxy` handlers to the query execution process in the `viewer backend`. * Fixed an error where the `/cluster` endpoint returned the root domain name, such as `/ru`, in the `viewer backend`. * Implemented a seamless table update scheme for `QueryService`. * Fixed an issue where `DELETE` returned data and did not delete it. * Fixed an error in `DELETE ON` operation in query service. * Fixed an unexpected batching disablement in `default` schema settings. * Fixed a triggering check `VERIFY failed: MoveUserTable(): requirement move.ReMapIndexesSize() == newTableInfo->Indexes.size()`. * Increased the `default` timeout for `grpc-streaming`. * Excluded unused messages and methods from `QueryService`. * Added sorting by `Rack` in /nodes in the `viewer backend`. * Fixed an error where sorting queries returned an error in descending order. * Improved interaction between `QP` and `NodeWhiteboard`. * Removed support for old parameter formats. * Fixed an error where `DefineBox` was not being applied to disks with a static group. * Fixed a `SIGSEGV` error in the dinnode during `CSV` import via `YDB CLI`. * Fixed an error that caused a crash when processing `NGRpcService::TRefreshTokenImpl`. * Implemented a `gossip protocol` for exchanging cluster resource information. * Fixed an error in `DeserializeValuePickleV1(): requirement data.GetTransportVersion() == (ui32) NDqProto::DATA_TRANSPORT_UV_PICKLE_1_0 failed`. * Implemented `auto-increment` columns. * Use `UNAVAILABLE` status instead of `GENERIC_ERROR` when shard identification fails. * Added support for rope payload in `TEvVGet`. * Added ignoring of deprecated events. * Fixed a crash of write sessions on an invalid topic name. * Fixed an error in `CheckExpected(): requirement newConstr failed, message: Rewrite error, missing Distinct((id)) constraint in node FlatMap`. * Enabled `self-heal` by default. ## Version 23.2 {#23-2} Release date: August 14, 2023. ### Functionality * **_(Experimental)_** Implemented visibility of own changes. With this feature enabled you can read changed values from the current transaction, which has not been committed yet. This functionality also allows multiple modifying operations in one transaction on a table with secondary indexes. To enable this feature add `enable_kqp_immediate_effects: true` under `table_service_config` section into [configuration file](https://ydb.tech/docs/en/reference/configuration/index.md). * **_(Experimental)_** Implemented read iterators. This feature allows to separate reads and computations. Read iterators allow datashards to increase read queries throughput. To enable this feature add `enable_kqp_data_query_source_read: true` under `table_service_config` section into [configuration file](https://ydb.tech/docs/en/reference/configuration/index.md). ### Embedded UI * Navigation improvements: * Diagnostics and Development mode switches are moved to the left panel. * Every page has breadcrumbs. * Storage groups and nodes info are moved from left buttons to tabs on the database page. * Query history and saved queries are moved to tabs over the text editor area in query editor. * Info tab for scheme objects displays parameters using terms from `CREATE` or `ALTER` statements. * Added [column tables](https://ydb.tech/docs/en/concepts/datamodel/table.md#column-tables) support. ### Performance * For scan queries, you can now effectively search for individual rows using a primary key or secondary indexes. This can bring you a substantial performance gain in many cases. Similarly to regular queries, you need to explicitly specify its name in the query text using the `VIEW` keyword to use a secondary index. * **_(Experimental)_** Added an option to give control of the system tablets of the database (SchemeShard, Coordinators, Mediators, SysViewProcessor) to its own Hive instead of the root Hive, and do so immediately upon creating a new database. Without this flag, the system tablets of the new database are created in the root Hive, which can negatively impact its load. Enabling this flag makes databases completely isolated in terms of load, that may be particularly relevant for installations, consisting from a roughly hundred or more databases. To enable this feature add `alter_database_create_hive_first: true` under `feature_flags` section into [configuration file](https://ydb.tech/docs/en/reference/configuration/index.md). ### Bug fixes * Fixed a bug in the autoconfiguration of the actor system, resulting in all the load being placed on the system pool. * Fixed a bug that caused full scanning when searching by prefix of the primary key using `LIKE`. * Fixed bugs when interacting with datashard followers. * Fixed bugs when working with memory in column tables. * Fixed a bug in processing conditions for immediate transactions. * Fixed a bug in the operation of iterator-based reads on datasharrd followers. * Fixed a bug that caused cascading reinstallation of data delivery sessions to asynchronous indexes. * Fixed bugs in the optimizer for scanning queries. * Fixed a bug in the incorrect calculation of storage consumption by Hive after expanding the database. * Fixed a bug that caused operations to hang on non-existent iterators. * Fixed bugs when reading a range on a `NOT NULL` column. * Fixed a bug in the replication of VDisks. * Fixed a bug in the work of the `run_interval` option in TTL. ## Version 23.1 {#23-1} Release date: May 5, 2023. To update to version 23.1, select the [Downloads](https://ydb.tech/docs/en/downloads/index.md#ydb-server) section. ### Functionality * Added [initial table scan](https://ydb.tech/docs/en/concepts/cdc.md#initial-scan) when creating a CDC changefeed. Now, you can export all the data existing at the time of changefeed creation. * Added [atomic index replacement](https://ydb.tech/docs/en/dev/secondary-indexes.md#atomic-index-replacement). Now, you can atomically replace one pre-defined index with another. This operation is absolutely transparent for your application. Indexes are replaced seamlessly, with no downtime. * Added the [audit log](https://ydb.tech/docs/en/security/audit-log.md): Event stream including data about all the operations on YDB objects. ### Performance * Improved formats of data exchanged between query stages. As a result, we accelerated SELECTs by 10% on parameterized queries and by up to 30% on write operations. * Added [autoconfiguring](https://ydb.tech/docs/en/reference/configuration/actor_system_config.md#autoconfig) for the actor system pools based on the workload against them. This improves performance through more effective CPU sharing. * Optimized the predicate logic: Processing of parameterized OR or IN constraints is automatically delegated to DataShard. * (Experimental) For scan queries, you can now effectively search for individual rows using a primary key or secondary indexes. This can bring you a substantial gain in performance in many cases. Similarly to regular queries, to use a secondary index, you need to explicitly specify its name in the query text using the `VIEW` keyword. * The query's computational graph is now cached at query runtime, reducing the CPU resources needed to build the graph. ### Bug fixes * Fixed bugs in the distributed data warehouse implementation. We strongly recommend all our users to upgrade to the latest version. * Fixed the error that occurred on building an index on NOT NULL columns. * Fixed statistics calculation with MVCC enabled. * Fixed errors with backups. * Fixed the race condition that occurred at splitting and deleting a table with SDC. ## Version 22.5 {#22-5} Release date: March 7, 2023. To update to version **22.5**, select the [Downloads](https://ydb.tech/docs/en/downloads/index.md#ydb-server) section. ### What's new * Added [changefeed configuration parameters](https://ydb.tech/docs/en/yql/reference/syntax/alter_table/changefeed.md) to transfer additional information about changes to a topic. * You can now [rename tables](https://ydb.tech/docs/en/concepts/datamodel/table.md#rename) that have TTL enabled. * You can now [manage the record retention period](https://ydb.tech/docs/en/concepts/cdc.md#retention-period). ### Bug fixes and improvements * Fixed an error inserting 0 rows with a BulkUpsert. * Fixed an error importing Date/DateTime columns from CSV. * Fixed an error importing CSV data with line breaks. * Fixed an error importing CSV data with NULL values. * Improved Query Processing performance (by replacing WorkerActor with SessionActor). * DataShard compaction now starts immediately after a split or merge. ## Version 22.4 {#22-4} Release date: October 12, 2022. To update to version **22.4**, select the [Downloads](https://ydb.tech/docs/en/downloads/index.md#ydb-server) section. ### What's new * YDB Topics and Change Data Capture (CDC): * Introduced the new Topic API. YDB [Topic](https://ydb.tech/docs/en/concepts/datamodel/topic.md) is an entity for storing unstructured messages and delivering them to various subscribers. * Added support for the Topic API to the [YDB CLI](https://ydb.tech/docs/en/reference/ydb-cli/topic-overview.md) and [SDK](https://ydb.tech/docs/en/reference/ydb-sdk/topic.md). The Topic API provides methods for message streaming writes and reads as well as topic management. * Added the ability to [capture table updates](https://ydb.tech/docs/en/concepts/cdc.md) and send change messages to a topic. * SDK: * Added the ability to handle topics in the YDB SDK. * Added official support for the database/sql driver for working with YDB in Golang. * Embedded UI: * The CDC changefeed and the secondary indexes are now displayed in the database schema hierarchy as separate objects. * Improved the visualization of query explain plan graphics. * Problem storage groups have more visibility now. * Various improvements based on UX research. * Query Processing: * Added Query Processor 2.0, a new subsystem to execute OLTP queries with significant improvements compared to the previous version. * Improved write performance by up to 60%, and by up to 10% for reads. * Added the ability to include a NOT NULL restriction for YDB primary keys when creating tables. * Added support for renaming a secondary index online without shutting the service down. * Improved the query explain view that now also includes fields for the physical operators. * Core: * For read only transactions, added consistent snapshot support that does not conflict with write transactions. * Added BulkUpsert support for tables with asynchronous secondary indexes. * Added TTL support for tables with asynchronous secondary indexes. * Added compression support for data export to S3. * Added an audit log for DDL statements. * Added support for authentication with static credentials. * Added system tables for query performance troubleshooting.