YDB Server changelog

Version 24.1

Release date: July 31, 2024.

Functionality

• The Knn UDF 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 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 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 replicas has been optimized, particularly when handling rapid updates for tables with a large number of partitions.

Bug fixes

• A possible queue overflow error has been fixed. Change Data Capture now reserves the change queue capacity during the initial scan.
• A potential deadlock between receiving and sending CDC records has been fixed.
• An issue causing the loss of the mediator task queue during mediator reconnection has been fixed. This fix allows processing of the mediator task queue during resynchronization.
• A rarely occurring error has been fixed, 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.
• 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.
• An issue causing read replicas to stop processing requests has been fixed.
• 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.
• 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.
• An error involving partial commits of a distributed transaction with uncommitted changes, caused by certain race conditions with restarts, has been fixed.
• Anomalies related to reading outdated data, detected using Jepsen, have been fixed.

Version 23.4

Release date: May 14, 2024.

Performance

• Fixed an issue of increased CPU consumption by a topic actor PERSQUEUE_PARTITION_ACTOR.
• Optimized 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 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 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 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 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 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 that caused the ydbd process to crash due to an incorrect session state when writing to a topic.
• Fixed a bug in displaying the metric of number of partitions in a topic, where it previously displayed an incorrect value.
• Fixed a bug 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

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. 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. This is important in cases where message processing order is not critical.
• YQL has added the capabilities to create, modify, and delete 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.
• (Experimental) Added support for reading from topics in a transaction. 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.
• (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 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 KQP 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

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.
• (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.

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 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.

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

Release date: May 5, 2023. To update to version 23.1, select the Downloads section.

Functionality

• Added initial table scan when creating a CDC changefeed. Now, you can export all the data existing at the time of changefeed creation.
• Added 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: 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 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

Release date: March 7, 2023. To update to version 22.5, select the Downloads section.

What's new

• Added changefeed configuration parameters to transfer additional information about changes to a topic.
• You can now rename tables that have TTL enabled.
• You can now manage the record 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

Release date: October 12, 2022. To update to version 22.4, select the Downloads section.

What's new

• YDB Topics and Change Data Capture (CDC):

  • Introduced the new Topic API. YDB Topic is an entity for storing unstructured messages and delivering them to various subscribers.
  • Added support for the Topic API to the YDB CLI and SDK. The Topic API provides methods for message streaming writes and reads as well as topic management.
  • Added the ability to capture table updates 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.