# 8.9 Release Notes

> **📝 Note**: - To deploy a SingleStore 8.9 cluster, refer to the [Deploy SingleStore Guide](https://docs.singlestore.com/db/v9.1/deploy.md).
> - To make a backup of a database in this release or to restore a database backup to this release, follow [this guide](https://docs.singlestore.com/db/v9.1/manage-data/back-up-and-restore-data.md).
> - New deployments of SingleStore 8.9 require a 64-bit version of RHEL/AlmaLinux 7 or later, or Debian 8 or later, with kernel 3.10 or later and `glibc` 2.17 or later. Refer to the [System Requirements and Recommendations](https://docs.singlestore.com/db/v9.1/reference/configuration-reference/cluster-configuration/system-requirements-and-recommendations.md) for additional information.

## Release Highlights

> **📝 Note**: This is the complete list of new features and fixes in SingleStore engine version 8.9.

## Full-Text Search - Analyzers and Tokenizers

Full-text search using SingleStore's VERSION 2 full-text index has been enhanced with support for custom analyzers and tokenizers. With this enhancement, SingleStore full-text indexes can be created to support languages other than English, for text that contains emails and URLs, with custom whitespace processing, and more. The n\_gram tokenizer, which breaks words into [n-grams](https://en.wikipedia.org/wiki/N-gram), sequences of n adjacent symbols is included. The full set of Apache Lucene analyzers and tokenizers is supported. Refer to [Full Text VERSION 2 Custom Analyzers](https://docs.singlestore.com/db/v9.1/developer-resources/functional-extensions/full-text-version-2-custom-analyzers.md) for more information.

## Full-Text Search - Enhanced BM25 Scoring

Full-text search using SingleStore's VERSION 2 full-text index has updated BM25 scoring functionality. 

The `BM25` function has been enhanced with support for boolean and boost queries, phrase and proximity search queries, and queries over multiple columns. Refer to [BM25](https://docs.singlestore.com/db/v9.1/reference/sql-reference/full-text-search-functions/bm-25.md) for more information and examples.

A new function, `BM25_GLOBAL`, has been added to provide BM25 scoring across all partitions. With this new function, all rows in a table are scored together; collection and term statistics are calculated for a table, ensuring accurate scores relative to all rows in a table. The `BM25_GLOBAL` function augments the existing `BM25` and `MATCH` functions, and it is more accurate and more expensive than both of these functions. Refer to [BM25](https://docs.singlestore.com/db/v9.1/reference/sql-reference/full-text-search-functions/bm-25.md) for more information on the `BM25_GLOBAL` function.

## Iceberg Continuous Ingest

Added support for continuous ingest of data from Iceberg tables. Upsert and append-only workloads are supported. In addition, manual upserts with the `CREATE OR REPLACE` command are supported. Refer to [Iceberg Ingest](https://docs.singlestore.com/db/v9.1/load-data/data-sources/iceberg-ingest.md) for more information.

## Iceberg - New Catalogs

Added support for Snowflake, REST, JDBC, Hive, and Polaris Catalogs for Iceberg Ingest using pipelines. Refer to [Iceberg Ingest](https://docs.singlestore.com/db/v9.1/load-data/data-sources/iceberg-ingest.md) for more information.

## Enhanced Disk Spilling

Added disk spilling for `RIGHT` and `FULL OUTER JOIN`. Refer to [Disk Spilling](https://docs.singlestore.com/db/v9.1/user-and-cluster-administration/maintain-your-cluster/managing-memory/disk-spilling.md) for more information.

## Writable Views

Writable views allow users to run `UPDATE`, `INSERT`, and `DELETE` queries on views. To enable writable views, set the `enable_writable_views` global variable to `1`. Query the `information_schema.VIEWS` view to inspect if a view can be updated. Refer to [CREATE VIEW](https://docs.singlestore.com/db/v9.1/reference/sql-reference/data-definition-language-ddl/create-view/#section-idm234617498191001.md) for more information.

## Other Improvements and Fixes

## Vector Index on Nullable Column

Vector Indexes can be created on columns that are nullable. Prior to this improvement, vector indexes could only be created on columns that were declared `NOT NULL`. With this improvement, a user can insert a row containing text and a `NULL` vector value into a table with a vector index. The user can subsequently obtain a vector embedding for the text and update the row with that vector value. The updated value will be added to the vector index.

## Vector Index Memory Tracking

The memory used by vector indexes can be tracked using the `alloc_vector_index` metric which is now available in [SHOW STATUS EXTENDED](https://docs.singlestore.com/db/v9.1/reference/sql-reference/show-commands/show-status-extended.md). Refer to [Vector Indexing](https://docs.singlestore.com/db/v9.1/reference/sql-reference/vector-functions/vector-indexing.md) and [Tuning Vector Indexes and Queries](https://docs.singlestore.com/db/v9.1/developer-resources/functional-extensions/tuning-vector-indexes-and-queries.md) for more information.

## Vector Index Merger

Added the vector index merger which combines per-segment vector indexes to create a cross-segment vector index and improve the performance of vector search queries. Refer to [Vector Indexing](https://docs.singlestore.com/db/v9.1/reference/sql-reference/vector-functions/vector-indexing.md) for more information.

## High Availability for the Master Aggregator

**Note**: This is a Preview feature and will be part of an upcoming add-on pricing package.

High availability (HA) for the Master Aggregator (MA) node enhances the reliability of mission-critical workloads. This feature automatically elects and promotes a new MA if the primary MA fails, ensuring the continuous operation of a cluster. Refer to [Multi-Datacenter Failover](https://docs.singlestore.com/db/v9.1/user-and-cluster-administration/high-availability-and-disaster-recovery/managing-high-availability/multi-datacenter-failover.md) for more information.

## Other Performance Enhancements

* **Enhancement**: Added sub-segment elimination for flexible parallelism. Refer to [Flexible Parallelism](https://docs.singlestore.com/db/v9.1/introduction/distributed-architecture/flexible-parallelism.md) for more information.
* **Enhancement**: Performance of full-text search, specifically throughput performance, has been significantly improved.
* **Enhancement**: Improved performance of `VECTOR` type user-defined variables (UDVs). These variables no longer require using extra typecast to `BLOB` data type.
* **Enhancement**: Improved the performance of `LOAD DATA` queries that include the `CHARACTER SET` clause.
* **Enhancement**: Improved performance of the `CREATE PROJECTION` command by skipping unique key checks.
* **Enhancement**: Improved the performance of `REPLACE` query into a columnstore table when table-level locking is triggered.
* **Enhancement**: Improved the performance of `CREATE {TABLE | TABLES} AS INFER PIPELINE` queries.
* **Enhancement**: Optimized full-text queries with `ORDER BY ... LIMIT` on a full-text score and that optionally filter on the same full-text clause.
* **Enhancement**: Significantly improved the performance (\~20x) of certain JSON-based SQL queries, when JSON objects contain arrays of sub-objects. This optimization reduces the need to normalize the data into multiple tables to achieve high analytics performance.

  Queries that expand JSON arrays (with or without any aggregations) and/or perform the following operations benefit from this optimization:

  * Group by a field outside the array (in the `GROUP BY` clause)
  * Filter on the fields in the array

## New Information Schema Views and Columns

* **Enhancement**: Added the `FUNCTION_NAME` column to the `MV_PROCESSLIST` information schema view to indicate when a query is invoked from a stored procedure and to display the stored procedure's name. (8.9.46)
* **Enhancement**: Added a new `BLOB_COMPUTE_ID` column for `COLUMNAR_SEGMENTS` and `MV_COLUMSTORE_FILES` information schema views. (8.9.38)
* **Enhancement**: Added a new column `MEMORY_USAGE_BYTES` to `LMV_RESOURCE_POOL_STATUS` and `MV_RESOURCE_POOL_STATUS` information schema views. (8.9.38)
* **Enhancement**: Added `ATTACH` / `DETACH` / `CREATE` / `DROP` to `information_schema.mv_events`. (8.9.35)
* **Enhancement**: Added the `ACTIVE_METADATA_VERSIONS` information schema view that provides visbiility into active metadata transaction read versions. (8.9.31)
* **Enhancement**: Added the `MV_GC_EVENTS` information schema view that provides visibility into garbage collection passes. This view is gated behind the preview feature and engine variable `enable_gc_events`. (8.9.31)
* **Enhancement**: Added the `TABLE_NAME` column to the `LOAD_DATA_ERRORS` information schema view. `TABLE_NAME` is the name of the table associated with the error.
* **Enhancement**: Added the `NODE_ID` column to the `MV_RECOVERY_STATUS` information schema view that specifies the ID of the node from which the database is being recovered.
* **Enhancement**: Added the `MV_BOTTOMLESS_API_EVENTS_SUMMARY` information schema view that contains a summary of remote API calls made from the engine. Refer to [MV\_BOTTOMLESS\_API\_EVENTS\_SUMMARY](https://docs.singlestore.com/db/v9.1/reference/information-schema-reference/unlimited-storage/mv-bottomless-api-events-summary.md) for more information.
* **Enhancement**: Added the following columns (metrics) to the `MV_BOTTOMLESS_STATUS_EXTENDED` and `MV_BOTTOMLESS_SUMMARY` information schema views:

  * `IS_BOTTLE_SERVICE_UP`: Indicates whether the bottle service is up.
  * `BOTTLE_SERVICE_UPTIME_DOWNTIME_SECS`: Specifies the minimum uptime when the bottle service is up and the maximum downtime when the bottle service is down.

## New Commands and Functions

* **Enhancement**: Introduced new [JSON\_BUILD\_ARRAY](https://docs.singlestore.com/db/v9.1/reference/sql-reference/json-functions/json-build-array.md) function. (8.9.5)
* **New feature**: Added the `FULLTEXT SERVICE STOP` command. This command stops the full-text V2 service running on any node connected to the aggregator on which the command is run. Refer to [FULLTEXT SERVICE STOP](https://docs.singlestore.com/db/v9.1/reference/sql-reference/operational-commands/fulltext-service-stop.md) for more information.
* **New feature**: Added the following [Identifier Generation Functions](https://docs.singlestore.com/db/v9.1/reference/sql-reference/identifier-generation-functions.md):

  * `UUID_TO_BIN`
  * `BIN_TO_UUID`
  * `IS_UUID`
* **New feature**: Added a `SHOW FULLTEXT SERVICE METRICS` command that displays the diagnostic metrics for the JLucene full-text search in JSON format. Refer to [SHOW FULLTEXT SERVICE METRICS](https://docs.singlestore.com/db/v9.1/reference/sql-reference/show-commands/show-fulltext-service-metrics.md) for more information.
* **New feature**: Added a `SHOW CDC EXTRACTOR POOL` command that displays information about the CDC-in pipelines. Refer to [SHOW CDC EXTRACTOR POOL](https://docs.singlestore.com/db/v9.1/reference/sql-reference/show-commands/show-cdc-extractor-pool.md) for more information.
* **New feature**: Added a new `JSON_MERGE_PATCH` function that merges two JSON objects into a single JSON object. Refer to [JSON\_MERGE\_PATCH](https://docs.singlestore.com/db/v9.1/reference/sql-reference/json-functions/json-merge-patch.md) for more information.
* **New feature**: Added support for Lateral Join. Lateral join allows a subquery in the `FROM` clause of a SQL query to reference another table in that same `FROM` clause, which can simplify query syntax. Refer to [Lateral Join](https://docs.singlestore.com/db/v9.1/reference/sql-reference/data-manipulation-language-dml/select/#lateral-join.md) for more information.

## New or Modified Engine Variables

Refer to [List of Engine Variables](https://docs.singlestore.com/db/v9.1/reference/configuration-reference/engine-variables/list-of-engine-variables.md) for information on each of the following engine variables.

* **Bugfix**: Fixed vector index and search to use internal memory allocator instead of malloc. (8.9.40)
* **Bugfix**: Fixed an issue in `ORDER BY` self-Join rewrite. (8.9.40)
* **Enhancement**: Added `optimizer_disable_limit_pushdown_below_external_udf` to disable the optimizer rewrite to push `LIMIT`s below external User Defined Functions (UDFs). (8.9.39)
* **Enhancement**: Added the `regexp_error_handling_level` engine variable was added; this variable controls the behavior of error handling for regexp operations. (8.9.38)
* **Enhancement**: Added the `managed_functions_max_connections` engine variable which makes the maximum number of HTTP connections per node for managed external functions, such as Python User Defined Function (UDF)s, configurable. (8.9.35)
* **Enhancement**: Added a `suppress_dml_warnings` global variable to suppress all DML query warnings. (8.9.35)
* **Enhancement**: Added an engine variable `optimizer_disable_subselect_to_join_cte_preprocess` which can be used to disable the subselect to join rewrite for CTE preprocessing before inlining or materialization. (8.9.16)
* **Enhancement**: Added an engine variable `optimizer_enable_merge_unioned_queries_rewrite` which can be used to enable or disable the rewrite that merges union queries. This variable is `ON` by default. (8.9.15)
* **Enhancement**: Added an engine variable `disk_plan_gc_pause_seconds_on_startup` that disables disk plan garbage collection on startup. This variable prevents hot plans from being unintentionally disk garbage collected. (8.9.11)
* **Enhancement**: Added a new engine variable `scheduler_slow_loop_seconds` that specifies the threshold for triggering the verbose logging of scheduler thread timing. (8.9.8)
* **Enhancement**: Added a new engine variable `scheduler_slow_ready_queue_seconds` that specifies the threshold for triggering logging of slow ready queue draining. (8.9.8)
* **Enhancement**: Introduced `pipelines_iceberg_data_workers_heap_size` global engine variable to control memory used by iceberg data processing. (8.9.5)
* **Enhancement**: Added a new engine variable `sync_partitions_timeout_sec` that specifies the timeout (in seconds) to synchronize the cluster metadata across the cluster.
* **Enhancement**: Added a new engine variable `disconnect_client_on_invalid_connection_state`. If enabled, client connections are closed when their state becomes invalid.
* **Enhancement**: Added a new engine variable `synchronize_reference_timeout_ms` that specifies the time (in seconds) long running queries wait for reference databases to synchronize on commit in the cluster.
* **Enhancement**: Added a new engine variable `assume_udfs_deterministic` that controls behavior where SingleStore does extra work to avoid issues caused by UDFs that return different values when called repeatedly (e.g., are non-deterministic).
* **Enhancement**: Added a new engine variable `max_autostats_update_workers` to tune the maximum number of background autostats update workers.
* **Enhancement**: Added a new engine variable `enable_writable_views` that enables creation of writable views. Refer to [CREATE VIEW](https://docs.singlestore.com/db/v9.1/reference/sql-reference/data-definition-language-ddl/create-view/#section-idm234617498191001.md) for more information.
* **Enhancement**: Added a new engine variable `recovery_concurrency` that controls the replay and database initialization concurrency during database recovery.
* **Enhancement**: Updated the minimum value of `json_document_max_children` engine variable to `1` (from `128` previously).
* **Enhancement**: Disabled the `optimize_json_computed_column` engine variable by default.
* **Enhancement**: Added a new engine variable `enable_block_level_stats_collection` that controls the collection of block-level statistics for sub-segment elimination for flexible parallelism.
* **Enhancement**: Added a new engine variable `enable_block_stats_use_in_query` that controls whether the block-level statistics are read and used during scan as part of sub-segment elimination for flexible parallelism.
* **Enhancement**: Added a new engine variable `pipelines_iceberg_heap_size` to control heap size specifically for Iceberg pipelines.
* **Enhancement**: Added `json_collation` global variable to control collation of JSON. The value of `json_collation` can be either `utf8_bin` or `utf8mb4_bin`.
* **Enhancement**: Added a method to throttle upload ingest when blob cache has low evictability and running out of disk space is imminent. This is controlled via the following two new engine variables:

  * `bottomless_upload_throttle_hard_limit_cache_usability`: The usability (free space + evictable space) of blob cache below which all columnstore ingest is throttled.
  * `bottomless_upload_throttle_soft_limit_cache_usability`: The usability (free space + evictable space) of blob cache below which some columnstore ingest is throttled.
* **Enhancement**: Added a new `optimizer_not_null_filter_derivation` engine variable that controls a new filter derivation rewrite.
* **Enhancement**: Added a new engine variable `external_functions_service_buffer_mb` that sets the maximum size (in MB) of the memory-mapped region used to communicate between the engine and collocated services.
* **Bugfix**: During the upgrade to SingleStore 8.9, if the value of `fts2_max_connections` is equal to `100000`, it is set to `32`.
* **Enhancement**: Added a new engine variable `early_snapshot_timeout_seconds` that specifies the time (in seconds) to wait after an `ALTER` or `TRUNCATE` command before taking an early snapshot.

## Miscellaneous

> **📝 Note**: SingleStore versions 8.9.46, 8.9.47, and 8.9.48 have been deprecated due to an issue with `JSON_EXTRACT_BIGINT`. Refer to the Known Issues section in each version's release notes for more information. If you are currently running any of these versions, SingleStore recommends upgrading to version 8.9.49 or later.

## Updates

* **Enhancement**: Added support for tracing DDL activity, allowing users to audit recent DDL statements across the cluster via [Query History](https://docs.singlestore.com/db/v9.1/query-data/query-tuning/query-history.md) and the [MV\_TRACE\_EVENTS](https://docs.singlestore.com/db/v9.1/reference/information-schema-reference/trace-events/mv-trace-events.md) information schema view. (8.9.52)
* **Enhancement**: Improved `IN`-subselect rewrite handling by not adding `ISNULL()` checks for non-nullable columns. (8.9.52)
* **Bugfix**: Fixed a crash that occurred when a subselect is used in the `WHERE` predicate of a `LOAD DATA` query. (8.9.52)
* **Bugfix**: Updated Netty package to 4.1.135.Final to address multiple Java Dependency CVEs. (8.9.52)
* **Bugfix**: Updated Golang to version 1.26.4 and addressed multiple CVEs in Golang supplementary modules `crypto`, `net` and `sys`. (8.9.52)

* **Bugfix**: Fixed a crash when writing to a view if the column names are cased differently from the column name in the view definition. (8.9.51)
* **Bugfix**: Fixed incorrect results for correlated `EXISTS` subqueries that contain `TABLE(SPLIT)`. (8.9.51)

* **Enhancement**: Updated the `KILLED_QUERIES` counter in Resource Governor pools to include queries terminated due to exceeding `QUERY_MEMORY_PERCENTAGE`. (8.9.50)
* **Enhancement**: Upgraded `librdkafka` to version 2.13.2. (8.9.50)
* **Enhancement**: Updated multiple dependencies and bundled components including the Go toolchain, Apache Thrift Go module, Netty, PostgreSQL, and OpenJDK JRE, to address security vulnerabilities. (8.9.50)
* **Bugfix**: Fixed a bug where an optimization on GROUP BY fields was incorrectly applied when grouping by a typecast expression. (8.9.50)

* **Bugfix**: Reverted a change to the `JSON_EXTRACT_BIGINT` function that could cause incorrect results or system crashes. (8.9.49)
* **Enhancement**: Improved join selectivity estimation for predicates of the form `col1 = IFNULL(col2, col3)` by leveraging column cardinality statistics. (8.9.48)
* **Enhancement**: Updated the `MV_COLUMNAR_SEGMENT_INDEX` information schema view to return the correct `INDEX_NAME` for multi-value hash indexes on JSON/BSON columns enabling accurate per-index size reporting. (8.9.48)
* **Enhancement**: Added the ability to avoid group by placement rewrites when grouped tables have no join predicates. This functionality improves query plan stability for multi-table aggregates. (8.9.48)
* **Bugfix**: Fixed an issue where regular expression patterns with character ranges ending in 0xFF could cause queries to hang. (8.9.48)
* **Bugfix**: Fixed an issue that caused duplicate repartition on join between derived table and reference table. (8.9.48)

* **Bugfix**:Fixed an issue where the system allowed creation of semantically identical multi-value indexes on the same column or JSON path. (8.9.47)

* **Bugfix**: Fixed an issue where `json_collation` was not synchronized with `character_set_server` after upgrading from version 8.5 or earlier to version 8.7 or later. (8.9.47)

* **Enhancement**: Improved performance for JSON integer and boolean extraction using `JSON_EXTRACT_BIGINT()`. The engine now operates on the encoded representation avoiding full JSON decoding; it decodes only needed values speeding up filters, grouping, and aggregates. (8.9.46)
* **Bugfix**: Added functionality to allow the engine to temporarily revert to prior memory tracking behavior which did not track result table memory. (8.9.46)
* **Bugfix**: Fixed a crash in `PERCENTILE_CONT()` that occured when the function was used with `ORDER BY` on a constant value. (8.9.46)

* **Enhancement**: Introduced background IO submission thread for sync durability and batching multiple IO requests. (8.9.45)
* **Enhancement**: Disabled prewritten ingest transformations by default. (8.9.45)
* **Enhancement**: Improved stored procedure exception handling to display full callstacks when using nested `RAISE` statements. (8.9.44)
* **Enhancement**: Improved stored procedure exception handling to preserve and display the original error line number when an exception is re-raised using the `RAISE` statement. (8.9.44)
* **Bugfix**: Fixed a crash when pipelines insert data into writable views. (8.9.44)
* **Bugfix**: Fixed a bug that caused stack overflow errors when executing complex queries with multiple joins in `compile_lite` and `compile_lite_first` interpreter mode. (8.9.44)
* **Bugfix**: Fixed an internal query conversion issue that caused a mismatch in vector join decisions between the aggregator and leaf nodes. (8.9.44)
* **Bugfix**: Updated Golang dependencies to address known Common Vulnerabilities and Exposures (CVEs) in container images and related components. (8.9.44)

* **Enhancement**: Disabled `critical_diagnostics` by default. (8.9.43)
* **Bugfix**: Fixed double accounting of memory via buffer allocators(`Alloc_spill`, `Alloc_arena`). Now, if memory is used from cache memory, total server memory remains unused. (8.9.43)
* **Bugfix**: Fixed a bug that caused a crash when a built-in Table-Valued Function (TVF) table is joined with a table with a join condition involving `JSON_ARRAY_CONTAINS_<type>`. (8.9.43)

* **Bugfix**: Fixed a Common Table Expression (CTE) preprocessing bug involving nested CTEs within `INTERSECT` and `EXCEPT` queries. (8.9.42)
* **Enhancement**: Added the ability for the orderby self join rewrite to skip heuristic checks when full JSON documents are projected. (8.9.41)
* **Bugfix**: Fixed a stack corruption bug exposed in very large queries. (8.9.41)
* **Bugfix**: Fixed an issue where `Alloc_spill` memory was not following Resource Governor memory limits. (8.9.41)
* **Bugfix**: Fixed Netty and OpenJDK Common Vulnerabilities and Exposures (CVEs). (8.9.41)
* **Bugfix**: Fixed affected row count for `SELECT .. FROM .. into FS/S3 ...` queries when row count is greater than 32-bit integer limits. (8.9.41)

* **Bugfix**: Fixed vector index and search to use internal memory allocator instead of malloc. (8.9.40)
* **Bugfix**: Fixed an issue in  ORDER BY self-Join rewrite. (8.9.40)
* **Enhancement**: Added an optimizer rewrite to push `LIMIT`s below external User Defined Functions (UDFs). (8.9.39)
* **Enhancement**: Limited the vector index cache size to keep it from getting to close to the maximum server memory. (8.9.39)
* **Enhancement**: Added `source_type` to the `config_json` shown in the `information_schema.PIPELINES view`. (8.9.39)
* **Enhancement**: Improved phonehome security by adding remote endpoint verification. (8.9.39)
* **Enhancement**: Upgraded the Almalinux version to Almalinux 10. (8.9.39)
* **Bugfix**: Resolved a crash that could occur when `TABLE(<constant>)` function appeared inside a subquery that was part of an `OR` or `AND` condition (for example nested `IN` and `EXISTS` clauses). (8.9.39)
* **Bugfix**: Disabled the optimize JSON computed column feature. (8.9.39)
* **Bugfix**: Fixed `RESTORE DATABASE` in highly-available master aggregator deployments. (8.9.39)
* **Bugfix**: Fixed an issue where `information_schema.MV_CLUSTER_STATUS` queries would be recursively forwarded to the master aggregator. (8.9.39)
* **Bugfix**: Fixed an issue where unsuccessful distributed transactions could lead to increased memory usage on aggregators. (8.9.39)
* **Bugfix**: Fixed an unchecked division when plan module eviction is triggered with no evictable plans. (8.9.39)

* **Enhancement**: Added collection of enhanced query stats from kill query Recursive Common Table Expressions (RCTE) writer statistics and sorted iterator error cases. (8.9.38)
* **Enhancement**: Added Unix timestamp versions of `start_time` and `event_time` fields in event trace samples exposed by monitoring exporter. (8.9.38)
* **Enhancement**: Modified ingestion to skip `NULL` records while using `SKIP ALL ERRORS` and `SKIP PARSER ERRORS` in Kafka pipelines. (8.9.38)
* **Enhancement**: Improved error handling for regular expressions: errors are now properly raised instead of returning SQL-NULL. The `regexp_error_handling_level` engine variable was added; this variable controls the behavior of error handling for regexp operations. (8.9.38)

* **Bugfix**: Resolved an issue where the regular expression engine would return SQL-NULL when hitting the memory limit during execution. It now raises an appropriate error instead. (8.9.38)
* **Bugfix**: Fixed an issue that caused a stalled cluster in the presence of many concurrent `DROP TEMPORARY TABLE` commands. (8.9.38)
* **Bugfix**: Fixed memory tracking for some queries which were not being tracked properly, result tables to be specific. (8.9.38)

* **Enhancement**: Added the ability to ignore join selectivity estimates of zero. (8.9.37)
* **Bugfix**: Fixed a situation where long running background work can block in-memory garbage collection of database metadata. (8.9.37)
* **Bugfix**: Fixed a memory allocation bug during query compilation. (8.9.37)
* **Bugfix**: Fixed a bug where large queries can crash the engine in `compile_lite` and `compile_lite_first` interpreter modes. (8.9.37)
* **Bugfix**: Fixed stack overflows in `compile_lite` and `compile_lite_first` interpreter mode. (8.9.37)
* **Bugfix**: Fixed a bug with some `NOT IN` subselect query shapes. (8.9.37)
* **Bugfix**: Limited the number of retries on plan compilation errors; this fix limits resource usage. (8.9.37)
* **Bugfix**: Fixed a deadlock in result table creation during reshuffle with the always-false filter. (8.9.37)

* **Enhancement**: Manually register the path to the Java 11 library. This path is set with the `java_pipelines_java11_path` engine variable. (8.9.36)
* **Enhancement**: Enabled using the estimated table row count as default column cardinality for better join estimation. Added session variable `optimizer_max_table_row_count_as_default_cardinality` which controls the maximum estimated table row count to be used as the per column cardinality. (8.9.36)
* **Bugfix**: Fixed a bug in the detection of shard key matches in the window function partition by list. (8.9.36)
* **Bugfix**: Fixed using Delimited Batch Sets with JSON format. (8.9.36)
* **Bugfix**: Fixed an issue where the `ALTER TABLE` command could hang and become unkillable due to a type conversion error occurring during the `ALTER` operation. (8.9.36)

* **Enhancement**: Removed the `CAST` operator if a redundant cast is performed. (8.9.35)
* **Enhancement**: Changed the approach for delimited batch sets. Delimited batch sets now return and accept original rowIDs. (8.9.35)
* **Enhancement**: Added support for metadata garbage collection for Azure pipelines. (8.9.35)
* **Bugfix**: Fixed an error in backup subprocess and enhanced subprocess tracing to use structured logging. (8.9.35)
* **Bugfix**: Fixed a crash when BM25 in a subselect references a table from the outer select. (8.9.35)
* **Bugfix**: Fixed an issue where certain commands (e.g. `DROP TABLE`) could hang due to aborted queries caused by stuck Collocated Services triggered by External Functions. (8.9.35)
* **Bugfix**: Fixed performance regression for queries involving JSON (like `JSON_EXTRACT_<type>` builtins) (8.9.35)
* **Enhancement**: Added knob to disable cardinality estimates on JSON/BSON columns during analyze. (8.9.34)
* **Bugfix**: Fixed query performance issue caused by heuristic estimate selectivity being overwritten. (8.9.34)
* **Bugfix**: Updated third party libraries to fix security vulnerabilities. (8.9.34)
* **Bugfix**: Fixed an issue where monitoring pipelines would sometimes fail to produce data for large source clusters. (8.9.34)
* **Bugfix**: Fixed row count estimation for union subquery containing Materialized Common Table Expression (MCTE)s. (8.9.34)

* **Bugfix**: Updated third party libraries to fix security vulnerabilities. (8.9.33)

* **Enhancement**: Added support for fully enclosed optimization on nullable columns and segment elimination on `IS NULL` filter. (8.9.31)
* **Bugfix**: Fixed incorrect results in an `ORDER BY <sort key> LIMIT` query, caused by an issue where rows with null values in the sort key may be skipped. (8.9.31)
* **Bugfix**: Fixed incorrect aggregation of leaf query stats in Query\_completion tracing. (8.9.31)

* **Enhancement**: Updated the bundled OpenSSL version to 3.1.2. (8.9.29)
* **Bugfix**: Bumped the \_bt timeout from 60 seconds to 180 seconds. (8.9.29)
* **Bugfix**: Fixed results for `NOT IN` subselects when the left input table has `NULL` values. (8.9.29)
* **Bugfix**: Fixed logic for `NOT IN` subselects when nested under `OR`s. (8.9.29)
* **Bugfix**: Fix correctness when using `NOT IN` for some query shapes. (8.9.29)

* **Enhancement**: Added Lucene logs to the cluster report. (8.9.28)
* **Bugfix**: Fixed a bug in lateral joins. (8.9.28)

* **Bugfix**: Fixed the predicate pushdown logic for materialized common table expressions. (8.9.27)
* **Bugfix**: Fixed an issue where periodic autostat was disabled when it should not have been. (8.9.27)

* **Bugfix:** Fixed crash in lockfree hashtable when engine is under high memory pressure. Report out of memory error instead. (8.9.26)
* **Enhancement**: Users with database visibility can now query the `*_BOTTOMLESS_*` information schema views in the respective database. `CLUSTER` permissions are no longer enforced for querying these views. (8.9.25)
* **Enhancement**: Improved the error message for parameter count mismatch during query parsing. (8.9.25)
* **Enhancement**: Disabled segment elimination for `IN` clauses for which the left-hand expression is not a table column. (8.9.25)
* **Bugfix**: Fixed a leak in a rare scenario. (8.9.25)
* **Bugfix**: Fixed the `ER_BAD_TABLE_ERROR` error on `UPDATE` or `DELETE` queries with a specific shape. (8.9.25)
* **Bugfix**: Fixed a crash in a shallow copy of a table with a pending `ALTER` operation. (8.9.25)
* **Bugfix**: Fixed a bug in CTE query rewrites. (8.9.25)
* **Bugfix**: Fixed a potential replay failure on a table that uses full-text version 2. (8.9.25)
* **Bugfix**: Fixed an issue where `IN`-list factorization did not work with newline characters around the `IN`-list. (8.9.25)

* **Enhancement**: Extended a rewrite to allow merging derived tables with json functions. (8.9.24)
* **Enhancement**: Changed the default blob cache size to 75% of the total disk for small disk config. (8.9.24)
* **Enhancement**: Enabled rewriting correlated subselects that depend on more than one outer table with conditions other than equality. (8.9.24)
* **Enhancement**: Prevented the destination table from being replaced by projection on update or delete. (8.9.24)
* **Enhancement**: Renamed GIN index to Multi-Value Hash Index. GIN keyword deprecated. (8.9.24)
* **Bugfix**: Fixed a bug that caused filter-aware optimizations to not be applied above MCTE when involved in hash joins. (8.9.24)
* **Bugfix**: Fixed a bug that occurred when CTEs are rewritten. (8.9.24)

* **Enhancement**: Added more metrics to the views, `MV_CLOUD_PER_COMPUTE_REMOTE_STATS` and `MV_CLOUD_REMOTE_STATS`, for tracking of retention log chunks and snapshots.(8.9.22)
* **Enhancement**: Added support for stopwords `token_filter` for custom analyzers for FTS VERSION 2. (8.9.22)
* **BugFix**: Fixed invalid optree from rewrite on union queries matching a very specific shape.(8.9.22)

* **Enhancement**: Added estimates for query memory usage based on static row count and row size estimates to improve Workload Manager (WM) memory management. (8.9.21)
* **Enhancement**: Added support to the GIN Index for BSON for expressions, built-in functions, user-defined variables (UDVs), and typecasting. User-defined functions (UDFs) and non-deterministic built-in functions, such as rand(), remain unsupported. (8.9.21)
* **Bugfix**: Fixed an issue that could lead to undefined behavior when a node failed concurrently with the computation of the replication distribution tree. (8.9.21)
* **Bugfix**: Fixed a `NULL` value inline bug by adding typecast operations above the referencing field. (8.9.21)
* **Bugfix**: Fixed an issue where a node that had not been upgraded could trigger undefined behavior if the node's `processlist` was queried while the node was processing an internal RPC. (8.9.21)

* **Enhancement**: Added a `KILL` option for the `DETACH DATABASE` command. (8.9.20)

* **Enhancement**: Improved optimization speed of parameterized `IN`-lists by limiting traversal depth. (8.9.19)
* **Enhancement**: Added support for delimited batch sets in external functions. (8.9.19)
* **Enhancement**: High Availability for the Master Aggregator (HA for MA) is now enabled exclusively for Enterprise edition. (8.9.19)
* **Enhancement**: `OPTIMIZE TABLE ... INDEX` is now more responsive to `KILL QUERY` statements. (8.9.19)
* **Bugfix**: Fixed a bug that caused `DROP DATABASE` to hang in a rare condition. (8.9.19)
* **Bugfix**: Fixed an issue that returned wrong results in pipelines in a rare race condition. (8.9.19)
* **Bugfix**: Fixed an issue that caused a crash when a query referenced too many tables. (8.9.19)
* **Bugfix**: Changed options for loading libpam.so. (8.9.19)
* **Bugfix**: Fixed a race condition that caused `DETACH DATABASE` to hang. (8.9.19)
* **Bugfix**: Fixed a buffer overflow issue that occurred while de-parameterizing a multi-column `IN`-list filter. (8.9.19)
* **Bugfix**: Fixed an issue to prevent LRU eviction from stalling when several table modules are stale. (8.9.19)
* **Bugfix**: Fixed a bug in `JSON_TO_ARRAY()` join pushdown optimization that occurred when the JSON value being extracted from `table_col` is a JSON array. (8.9.19)

* **Enhancement**: General improvements and optimizations for `CHECK BOTTOMLESS CHECKSUM` command. (8.9.18)
* **Enhancement**: Added support for JSON arrays in pipelines loading JSON files. Each JSON record in the array is loaded as a separate row. (8.9.18)
* **Bugfix**: Fixed `ALTER RESOURCE POOL` to respect queue depth constraints. (8.9.18)
* **Bugfix**: Fixed a bug that produced incorrect results when performing a hash join with a condition that compares mismatched types where one of the types is BSON. (8.9.18)
* **Bugfix**: Fixed a crash caused by libgcc btree bug. (8.9.18)
* **Bugfix**: Reduced contention on a global lock controlling modules, affecting code loading and unwinding of exceptions. (8.9.18)
* **Bugfix**: Removed garbage collection from cleaning up arrangements when such garbage collection is already in process. (8.9.18)

* **Bugfix**: Fixed an issue impacting creating or a altering resource pool with a CPU percentage limitation after a MA failover. (8.9.17)

* **Bugfix**: Fixed CTE subselect to join preprocessing in the `INTERSECT`/`EXCEPT` CTE case. (8.9.16)
* **Bugfix**: Reserved memory space for `segment_id` in the pseudo column's MemoryFile. (8.9.15)
* **Bugfix**: Fixed a bug that occurred when a query used `I0` as a column name. (8.9.15)
* **Bugfix**: Fixed a crash that was due to an issue with the rewrite that merges union queries. (8.9.15)

* **Enhancement**: Added support for the `LIMIT` clause in prepared statements.(8.9.14)
* **Enhancement**: Added an option to run queries that failed asynchronous compilation, allowing users to introspect the compilation results..(8.9.14)
* **Bugfix**: Fixed an issue to prevent a crash when `JSON_TO_ARRAY` optimization is run against non-nullable JSON columns..(8.9.14)

* **Enhancement**: Added enhanced query tracing in `Query_completion` event traces. Refer to [Query History](https://docs.singlestore.com/db/v9.1/query-data/query-tuning/query-history.md) for details. (8.9.13)
* **Enhancement**: Added the ability for a user to change the login password when the variable `password_expiration_mode` is set to LIMITED\_ACCESS. Now the user is allowed to login even after the password expires but can only execute commands that update the password such as `ALTER USER` or `SET PASSWORD`. (8.9.13)
* **Enhancement**: Added a password expiry warning message that is raised each time the user executes a query. This warning starts appearing 14 days before the password actually expires. (8.9.13)
* **Enhancement**: Added auditlogging mode for only the root user. It is a startup-only variable similar to other audit logging configuration variables and should be set along with the `auditlog_level`. (8.9.13)
* **Bugfix**: Fixed a bug that caused a node to crash when the variable `ignore_foreign_keys` is `ON` and the `ALTER TABLE` command is used to add a foreign key. (8.9.13)
* **Bugfix**: Changed the output projection DDL to `CREATE PROJECTION`  instead of `CREATE TABLE _$_table_name_$ _` in debug profile. (8.9.13)
* **Bugfix**: Fixed an issue where DDL statements that were concurrent with PROMOTE AGGREGATOR TO MASTER did not get forwarded to the new Master Aggregator.
* **Bugfix**: Fixed a bug to prevent a crash when using FTS v2 with CTE. (8.9.13)

* **Bugfix**: Fixed a bug that caused incorrect results when running `INFER PIPELINE CSV`. (8.9.12)
* **Bugfix**: Fixed a rare deadlock occurring when DETACH DATABASE is run. (8.9.12)

* **Enhancement**: Added an internal allocator `Alloc_connection_context` which tracks certain per-connection allocations that were previously tracked using the standard allocator. (8.9.11)
* **Bugfix**: Fixed a crash that occurred when aggregator functions are used with `VECTOR` type data inside other built-ins. (8.9.11)
* **Bugfix**: Fixed the `userDictionary` parameter for the korean full-text tokenizer. (8.9.11)

* **Enhancement**: Added a vector index cache to limit the amount of memory used by vector indexes. Refer to [Vector Indexing](https://docs.singlestore.com/db/v9.1/reference/sql-reference/vector-functions/vector-indexing.md) for details. (8.9.10)
* **Enhancement**: Extended the [VECTOR\_SUM](https://docs.singlestore.com/db/v9.1/reference/sql-reference/vector-functions/vector-sum.md) aggregate function to support the `VECTOR` data type. (8.9.10)
* **Enhancement**: Computed column definitions now support the `SPLIT` function. (8.9.10)
* **Enhancement**: The `DROP` and `ALTER TABLE` commands no longer have to wait for the plan garbage collector. (8.9.10)
* **Bugfix**: Fixed a crash occurring when a table-valued function (TVF) column is used in a `WHERE` clause without a wrapping `JSON_EXTRACT` function in a `TABLE(JSON_TO_ARRAY())` join. (8.9.10)
* **Bugfix**: Fixed a bug that caused CDC-in pipelines to fail while inferring the table schema, with the "Failed to allocate slot in the extractor pool" error. (8.9.10)
* **Bugfix**: Fixed a deadlock between `ALTER` and failover in a rare race condition. (8.9.10)
* **Bugfix**: Fixed a critical issue where clusters were failing to connect to AWS remote storage due to CURL request timeouts. (8.9.10)
* **Bugfix**: Fixed a bug where a CDC pipeline gets stuck while waiting for data. (8.9.10)

* **Bugfix**: Fixed support for plan pinning in `IN` list factorization. (8.9.9)
* **Bugfix**: Fixed a bug that prevented proper error handling on socket timeout. (8.9.9)
* **Bugfix**: Fixed a bug in `JSON_ARRAY_CONTAINS_STRING` query rewrite for query shapes with the `LIMIT` clause. (8.9.9)

* **Enhancement**: Improved pipeline error clearing. Additional errors are cleared when `CLEAR PIPELINES ERRORS` is run or when the `pipelines_errors_retention_minutes` limit is reached. (8.9.8)
* **Bugfix**: Fixed a bug in lateral join to preserve projection field aliases for lateral join subselects. (8.9.8)

* **Enhancement**: Improve behavior of garbage collection for plancache. (8.9.7)
* **Bugfix**: Fixed a bug caused by using a (cross-segment) vector index ([Vector Indexing](https://docs.singlestore.com/db/v9.1/reference/sql-reference/vector-functions/vector-indexing/#section-idm234571614690074.md)) with null vectors. Users on prior 8.9 versions will need to recreate (drop and add) vector indexes for this fix to be effective as the cross-segment indexes are built in the background. (8.9.7)

* **Bugfix**: Fixes a data-dependent crash condition occurring in certain `TABLE(JSON_TO_ARRAY(...` joins introduced in version 8.9. (8.9.6)
* **Enhancement**: Added new nori (Korean) analyzer customizations for Full-Text Search V2. (8.9.5)
* **Enhancement**: Added support for updated Standard and Enterprise licenses. (8.9.5)
* **Enhancement**: Added logging for LRU compiled unit eviction. (8.9.5)
* **Enhancement**: Introduced support for placeholders for partition ID and timestamp in the `SELECT INTO ... file name` command. (8.9.5)
* **Bugfix**: Fixed a bug causing accumulation of .rem files on disk. (8.9.5)
* **Bugfix**: Fixed out of memory (OOM) errors and extra memory usage in Iceberg ingest. (8.9.5)
* **Bugfix**: Fixed a small memory bug in columnstore scans that use the `JSON_TO_ARRAY` join optimization. (8.9.5)

* **Bugfix**: Fixed a crash in `JSON_EXTRACT_STRING`. (8.9.4)
* **Bugfix**: Fixed a bug with updates and asserts using `JSON_ARRAY_CONTAINS_<type>` predicates. (8.9.4)
* **Bugfix**: Fixed bottomless upload throttling criteria. (8.9.4)
* **Bugfix**: Blocked creation of temporary table as a shallow copy. (8.9.4)
* **Bugfix**: Resolved an issue where an in-development subsystem can leak files on disk. (8.9.4)

* **Enhancement**: Relaxed dependency on partition count of leaf nodes for leaf plans. (8.9.3)
* **Enhancement**: Added Korean language analyzer for full-text search V2. (8.9.3)
* **Enhancement**: Added support to infer CSV files with a single column when the file contains no field terminators in any record. (8.9.3)
* **Bugfix**: Fixed handling of heartbeat messages in the MongoDB® extractor in debug mode. (8.9.3)
* **Bugfix**: Fixed display of default BSON and string values with null-terminators in the information\_schema. (8.9.3)
* **Bugfix**: Removed trailing dot for decimal column types that have scale equal to 0. (8.9.3)
* **Bugfix**: Fixed `IN`-list index matching for columnstore tables when a query has multiple `IN`-list predicates. (8.9.3)
* **Bugfix**: Fixed a bug that caused an invalid optree error after the `JsonArrayContainsToTableBuiltin` rewrite. (8.9.3)

* **Bugfix**: Fixed a crash that occurred during spilling when executing a query with a large number of `GROUP BY` columns. (8.9.2)
* **Bugfix**: Fixed performance regression in Vector Search when using `DOT_PRODUCT` metric. (8.9.2)
* **Bugfix**: Added an optional 'swap\_time' argument to `UUID_TO_BIN` and `BIN_TO_UUID` functions. (8.9.2)
* **Bugfix**: Allowed cached table memory to be freed for empty tables in replica databases. (8.9.2)
* **Bugfix**: Fixed a latera l join parsing bug. (8.9.2)

## 8.9

* **Enhancement**: Added the `DETERMINISTIC` clause to the `CREATE FUNCTION` (UDF) command that instructs the query optimizer to assume that the created function is deterministic. Refer to [CREATE FUNCTION (UDF)](https://docs.singlestore.com/db/v9.1/reference/sql-reference/procedural-sql-reference/create-function-udf.md) for more information.
* **Enhancement**: Added support for the `IGNORE <n> LINES` clause to the `INFER PIPELINE` command for CSV files. Refer to [Schema and Pipeline Inference](https://docs.singlestore.com/db/v9.1/load-data/about-singlestore-pipelines/pipeline-concepts/schema-and-pipeline-inference.md) for more information.
* **Enhancement**: Added a query rewrite for correlated sub-selects that allows many additional types of queries with correlated sub-selects to now run successfully.
* **Enhancement**: Added support for using the `SKIP ALL ERRORS` clause during creation of Kafka pipelines for ingesting JSON formatted data.
* **Enhancement**: Added support for `SKIP ALL ERRORS` and `SKIP PARSER ERRORS` clauses during creation of Kafka pipelines for ingesting Avro formatted data.
* **Enhancement**: Added the ability to load Kafka properties and headers with the `get_kafka_pipeline_prop("<property>")` function.
* **Enhancement**: Added the ability to override the `pipelines_max_offsets_per_batch_partition` global variable for each Kafka pipeline using the `MAX_OFFSETS_PER_BATCH_PARTITION` pipeline variable in `CREATE PIPELINE` and `ALTER PIPELINE` commands.
* **New feature**: Added support for the following parameters in the `CONFIG` clause of `CREATE PIPELINE AS ... LOAD DATA S3` statement:

  * `file_compression`: Decompresses files with the specified extensions.
  * `file_time_threshold`: Only ingest files modified after the specified timestamp.

  Refer to [S3 Configurations](https://docs.singlestore.com/db/v9.1/load-data/data-sources/configuration-options-for-different-sources/#section-idm234488319463038.md) for more information.
* **Enhancement**: Added ability to re-optimize a query multiple times. Refer to [Query Tuning](https://docs.singlestore.com/db/v9.1/query-data/query-tuning/#section-idm234346860053849.md) for more information.
* **Enhancement**: Added the ability to use connection links to load Avro and Parquet formatted data stored in an AWS S3 bucket.
* **Enhancement**: Enabled auto [PROFILE](https://docs.singlestore.com/db/v9.1/reference/sql-reference/data-manipulation-language-dml/profile.md) for `INSERT...SELECT` and `REPLACE...SELECT` query shapes.
* **New feature**: Added the `ENABLE_OVERWRITE` clause in the `SELECT ... INTO S3` and `SELECT ... INTO LINK` statements that enables the overwriting of existing files. Refer to [SELECT … INTO S3](https://docs.singlestore.com/db/v9.1/reference/sql-reference/data-manipulation-language-dml/select/#select-into-s-3.md) for more information.
* **Enhancement**: Updated [PROFILE](https://docs.singlestore.com/db/v9.1/reference/sql-reference/data-manipulation-language-dml/profile.md) to show `number_of_blocks_tested_for_block_elim` and `number_of_blocks_eliminated_for_block_elim` for sub-segment elimination for flexible parallelism.
* **Enhancement**: Updated the `JSON_EXTRACT_<type>` functions to accept a JSON document as the only argument. With this enhancement, it is possible to extract from JSON documents with a string, numeric, boolean, or `NULL` value as the root of the document.
* **Enhancement**: Updated the simplified syntax for the `JSON_MATCH_ANY()` function, to allow specifying `MATCH_ELEMENTS` by appending a `*` to the end of the keypath.
* **Enhancement**: Added the ability to load CSV and JSON files from an Amazon S3 bucket using a `LOAD DATA` query.
* **Enhancement**: Enhanced the `TABLE()` function to support `DISTINCT`.
* **Enhancement**: Improved recovery time for tables with incremental autostats by recovering statistics from disk instead of rebuilding them from scratch.
* **Bugfix**: Fixed an issue that caused a deadlock between the `DROP TABLE` and `AGGREGATOR SYNC AUTO_INCREMENT` queries.
* **Enhancement**: Improved the logic for selecting vectors close to vector threshold in vector range search.
* **Bugfix**: Fixed an issue where attaching a leaf node to the Master Aggregator (MA) failed if the MA was still starting up.
* **Enhancement**: Added support for BM25 partition-scoped scoring for phrase and proximity search queries.
* **Enhancement**: Improved columnstore hash index performance on low cardinality column.
* **Enhancement**: Improved the Debezium DDL statements parser.
* **Enhancement**: Added row count estimate for joins in the output of `EXPLAIN` and `PROFILE` queries.
* **Enhancement**: Added support for `LIMIT` and `OFFSET` clauses in non-equality `WHERE` conditions in subselects.
* **Enhancements**: Added support for `LATERAL` joins for table-valued functions (TVFs).
* **Enhancement**: `SYNC DURABILITY` is always enabled for reference databases. Reference tables in user databases that use async durability may notice a decrease in performance for DDL and DML statements.
* **Enhancement**: Added support for `HIGHLIGHT ... AGAINST` as a computed column expression when creating a new table.
* **Enhancement**: Added support for a query rewrite that enables hash joins when two tables are joined using the `JSON_ARRAY_CONTAINS_<type>` function.
* **Enhancement**: Added support for sub-select to join rewrites for correlated subselects and nested scalar subselects.
* **Enhancement**: Added support for null-accepting projections in scalar subselect queries.
* **Enhancement**: Added support for `LATERAL` join subselects to reference any level of outer tables.
* **Enhancement**: Changed the default collation to `utf8mb4_general_ci` and default character set to `utf8mb4` for `TEXT` and `ENUM` type columns for `CSV`, `JSON`, `AVRO`, and parquet formats in `INFER PIPELINE AS LOAD DATA` statements.
* **Bugfix**: Fixed an issue that caused dangling compute sessions after a failed `ALTER DATABASE` command.
* **Bugfix**: Fixed an issue where concurrent `ALTER DATABASE` and `REBALANCE` operations create unlimited storage partitions with wrong compute ID.
* **Bugfix**: Fixed a race condition between the transaction log garbage collection and database transition-to-master that could result in unrecoverable partitions.
* **Enhancement**: Updated the distributed OpenSSL license file to 1.0.2zj.
* **Enhancement**: Added support for multi-column `IN` list predicate in the `WHERE` clause of a query.
* **Enhancement**: Function mapped `IN`-lists now share the same signature in the plancache for the same set of built-in functions.
* **Bugfix**: Removed soft lock on the `CHARACTER SET` clause and added a warning to indicate invalid character set value in the `LOAD DATA` statement.
* **Bugfix**: Database names can no longer end with big numbers, such as `db_<big_number>`, to avoid conflicts with internal databases used in replication.
* **Enhancement**: Each node in the cluster now validates the availability of bottle service every minute and records any consecutive failures in the `LMV_EVENTS` information schema view.
* **Enhancement**: Added more information to the out-of-memory (OOM) errors.
* **Bugfix**: Fixed an issue that occurred while parsing manifest files (associated with backup or restore operations) having more than 4096 characters.
* **Bugfix**: Fixed an issue that caused duplication of storage blobs that have not been repaired yet for ongoing repair operations.
* **Bugfix**: Fixed an issue in MySQL CDC-in pipelines where some MySQL tables with names containing `_` were not being replicated.
* **Bugfix**: Fixed a race condition that caused shutdown to wait on idle async compile manager thread.
* **Bugfix**: Fixed an issue where repair operation gets stuck while converting milestones.
* **Bugfix**: Fixed a synchronization issue where the database was not immediately available after some clustering operations.
* **Enhancement**: Added the estimated number of partitions returned by the query optimizer for cost-based join order optimization to the debug profile.
* **Enhancement**: Added support for `VECTOR` type in `REDUCE` built-in function.
* **Enhancement**: Improved the lockdown message when changing collation or character set related engine variables within `utf8mb4` character set.
* **Bugfix**: Fixed an issue with `PROMOTE AGGREGATOR ... MASTER` command where a restart at the end of the command, followed by manually finishing the promote operation, caused reprovisioning of the old Master Aggregator.
* **Bugfix**: Fixed an issue that caused an empty network prefetch queue.
* **Bugfix**: Fixed a distributed deadlock caused by a query blocking reference database reprovisioning in one part of the deadlock cycle.
* **Enhancement**: Added the following headers to Data API responses:

  * `Cache-control: no-store`
  * `Strict-Transport-Security: max-age=31536000`
  * `X-Content-Type-Options: nosniff`
* **Bugfix**: Fixed an issue with counting common table expressions (CTEs) references in a query.
* **Bugfix**: Fixed a memory corruption issue caused by a rare race condition involving `MV_ACTIVE_TRANSACTIONS` information schema view.
* **Enhancement**: Sharding planner now recognizes non-union style single partitioned derived table.
* **Enhancement**: Disabled pipeline batches sample by default in `memsql_exporter`.
* **Enhancement**: Improved message for an error where a global variable cannot be set because of a table sharded on a computed column.
* **Enhancement**: Improved connection stability for MongoDB® CDC-in pipelines.
* **Enhancement**: Upgraded the [librdkafka](https://github.com/confluentinc/librdkafka) library to version 2.4.0-3.
* **Bugfix**: Fixed an issue where the Master Aggregator (MA) temporarily stopped behaving as the MA after being restarted.
* **Enhancement**: Improved the performance of cluster operations through distributed plancache.
* **Bugfix**: Fixed a bug with incorrect privilege checks.
* **Enhancement**: Optimized row locking for internal transactions.
* **Enhancement**: Improved performance of `REVOKE` in case of errors.
* **Bugfix**: Fixed an engine crash caused when the Master Aggregator received a `REMOVE AGGREGATOR` query with its own `<host>:<port>`.
* **Enhancement**: Reduced the chances of reference database reprovisioning in universal storage if a snapshot is taken concurrently with Master Aggregator shutdown.
* **Enhancement**: `TO_JSON()` and `JSON_BUILT_OBJECT()` built-in functions now convert `VECTOR` type arguments to JSON array instead of a JSON string.
* **Enhancement**: Added support for ZSTD compressed Kafka topics to Kafka pipelines.
* **Bugfix**: Fixed an issue where `ClampTimestamp` spammed the tracelog.
* **Enhancement**: Limit DR connection attempts to the primary node when it is failing connections, avoiding a substantial increase in `TIME_WAIT` sockets.
* **Enhancement**: Improved error messages related to reprovisioning.
* **Enhancement**: Implemented rotation and deletion of webproxy socket logs.
* **Enhancement**: Ingest Kafka headers into the SingleStore table if they are included in the Kafka message.
* **Enhancement**: Lockdown hints for common table expressions (CTEs).
* **Enhancement**: Locked select and row count hints for multi-table views.
* **Bugfix**: Fixed an issue where slow snapshots blocked clustering operations.
* **Bugfix**: Fixed an issue where unrecoverable reference databases did not auto-heal for a prolonged period of time and get blocked, for example, by alter operations.
* **Enhancement**: Improved the error message for `Correlated subselect that cannot be transformed and does not match on shard keys` errors.
* **Bugfix**: Fixed data loss in sync durability in a rare race condition.
* **Enhancement**: Improved processing of queries with redundant (superfluous) `EXISTS` subselects.
* **Bugfix**: Fixed the reference count of committed blobs on upgrade.
* **Enhancement**: Added the `ON NODE <node_id>` clause to the `SHOW PROFILE` command, which forwards the command to another aggregator.
* **Enhancement**: Improved enforcement of `internal_columnstore_max_uncompressed_blob_size` engine variable.
* **Enhancement**: Added a new clause `ENSURE_PARTITION_SAFETY` to the `REMOVE {LEAF | LEAVES}` command that prevents a leaf (or leaves) from being removed if it contains the last online instance of a partition.
* **Enhancement**: The `memsql_exporter` now collects additional fields from the `mv_activities_extended_cumulative` information schema view.
* **Enhancement**: Optimized full-text queries that contain an `ORDER BY ... LIMIT ...` over a full-text score and optionally filter on the same full-text clause.
* **Enhancement**: Added support for numeric range queries when doing full-text search against JSON fields.

  Refer to [numeric range queries](https://docs.singlestore.com/db/v9.1/developer-resources/functional-extensions/working-with-full-text-search.md) for more information.
* **Enhancement**: Set collation `utf8_bin` for the `JSON_TO_ARRAY` builtin in cases where the input has `utf8` character set, and set collation `utf8mb4_bin` in cases where the input has `utf8mb4` character set.
* **Enhancement**: If a primary key is defined for the table, the `DELETE` change records for `OBSERVE` queries now populate the primary key for tables instead of the internal ID.
* **Enhancement**: Added information on remote API calls and bottle service reliability metrics to `MV_BOTTOMLESS_STATUS_EXTENDED` information schema view.
* **Enhancement**: Added metrics to track the availability of unlimited storage and the bottle service to `MV_BOTTOMLESS_SUMMARY` information schema view.
* **Enhancement**: Updated the syntax of `JSON_MATCH_ANY()` to allow specifying `MATCH_ELEMENTS` by appending a `*` at the end of the keypath.
* **Enhancement**: Additional binlog position updates for CDC-in pipelines in the extractor pool queue.
* **Enhancement**: Information schema queries are no longer case-insensitive with respect to database names.
* **Enhancement**: Allow rewrite for joining tables on the `JSON_ARRAY_CONTAINS_<type>` function to support multiple predicates of that form on different columns.
* **Bugfix**: Fixed a snapshot not found error.
* **Bugfix**: Fixed an issue where the result of a seek operation was not handled correctly.
* **Enhancement**: Detect scalar subselect requirement at runtime rather than rewrite time for certain cases.
* **Bugfix**: Fixed a bug in full-text search query compilation.
* **New Feature**: High availability for the Master Aggregator (HA for MA) has been introduced. This enhances the reliability and failover capabilities, allowing mission-critical workloads to remain highly available. Refer to [Multi-Datacenter Failover](https://docs.singlestore.com/db/v9.1/user-and-cluster-administration/high-availability-and-disaster-recovery/managing-high-availability/multi-datacenter-failover.md) for more information.
* **Enhancement**: Enabled `LOAD DATA` queries to use the specified `CHARACTER SET` to ingest [string type](https://docs.singlestore.com/db/v9.1/reference/sql-reference/data-types/string-types.md) fields.
* **Enhancement**: Improved performance of queries that use the `RAND()` builtin or constant expressions involving `PARTITION_ID`.
* **Enhancement**: Added support for a query rewrite when `UNION` is used to merge queries that reference the same tables and have mutually exclusive filters.
* **Bugfix**: Fixed a rare issue where `ALTER` operation and two-phase commit (2PC) caused index corruption.
* **Bugfix**: Fixed an issue that caused a crash when the global collation or character was set to a value with the prefix "utf8mb3".
* **Bugfix**: Fixed an issue that returned incorrect results when `JSON_MATCH_ANY()` and `BSON_MATCH_ANY()` queries contained nested `JSON_EXTRACT_<type>()`, `JSON_MATCH_ANY()`, `BSON_EXTRACT_<type>`, or `BSON_MATCH_ANY()` functions.
* **Bugfix**: Fixed a rare undefined behavior issue caused by `SHOW CLUSTER STATUS` command.
* **Bugfix**: Fixed an issue caused when multi-part names were used in common table expressions (CTEs) within UNION.
* **Bugfix**: Fixed an issue that caused `DROP DATABASE` and some other cluster management commands to wait indefinitely for resources.
* **Bugfix**: Fixed a rare issue that caused autostats file leak.
* **Bugfix**: Fixed a rare issue that blocked kill query operations.
* **Bugfix**: Fixed CVE-2024-45772 and BDSA-2024-0720 security vulnerabilities.
* **Bugfix**: Fixed an error in `BSON_MATCH_ANY()` pushdown.
* **Bugfix**: Fixed the result of `ORDER BY <sort_key> LIMIT` query on tables with a sort key column defined in the descending order.
* **Bugfix**: Fixed an issue that caused uneven time distribution in the CDC extractor pool.
* **Bugfix**: Fixed an issue that delayed restart of nodes with multiple reference databases.
* **Bugfix**: Fixed an issue where some point-in-time-recovery (PITR) operations failed when started from a restored snapshot.
* **Enhancement**: Upgraded Apache Lucene search engine library to 10.0.0.
* **Bugfix**: Fixed a bug that caused a query to fail in a specific situation when using `SEARCH OPTIONS` with vector index search.
* **Bugfix**: Fixed an edge case; common table expressions (CTEs) are now recognized in subselect to join rewrite.
* **Bugfix**: Fixed a bug that led to a master aggregator crash when using dynamic resource pools.
* **Enhancement**: Added support for Iceberg v2 merge-on-read ingest mode.
* **Bugfix**: Fixed ingest streaming logic for large Iceberg v2 tables.

## In this section

* [Maintenance Release Changelog v8.9](https://docs.singlestore.com/db/v9.1/release-notes/singlestore-memsql/8-9-release-notes/maintenance-release-changelog-v-8-9.md)

***

Modified at: June 23, 2026

Source: [/db/v9.1/release-notes/singlestore-memsql/8-9-release-notes/](https://docs.singlestore.com/db/v9.1/release-notes/singlestore-memsql/8-9-release-notes/)

(An index of the documentation is available at /llms.txt)