SingleStoreDB 9.0 Release Announcement

Enhancements

• Added the  disk_ plan_ gc_ pause_ minutes_ for_ detached_ tables  engine variable that specifies the number of seconds to cache detached table modules before eviction from disk.

• Added events to indicate the start and end of asynchronous upgrades.

• Added the  ENSURE_ ONLINE_ NODES  clause to the REBALANCE ALL DATABASES and REBALANCE PARTITIONS commands that allow rebalancing to run only if all the leaf nodes are online.

• Allowed background merger to run while OPTIMIZE TABLE is running.

• For deployments with a small disk size, changed the default blob cache size to 75% of the disk.

• Connected the distributed plancache to the plancache manager.

• Disabled unnecessary collection of block statistics.

• Added functionality to periodically output  MV_ PROCESSLIST  from Bottle Service to improve debugging.

• Implemented exponential backoff sleep between batch retries.

• Added support for heartbeat for bottle service while creating a bottle service link.

• All distributed plancache operations are now asynchronous.

• Added support for reusing the autostats file on recovery.

• Added support for spilling if input data has NULL rows.

• Aggregators now periodically synchronize query plans across the deployment.

• DROP RESOURCE POOL command cannot delete the current resource pool anymore.

• SingleStore now waits until asynchronous upgrade steps complete before taking a snapshot.

• Added support for NULL type in Wasm UDF return types and parameters.

• Added support for expressions, built-in functions, and user-defined variables in addition to hex literals in the Multi-Value index for BSON.  Refer to Multi-Value Hash Index (BSON) for more information.

• Extended redundant GROUP BY detection of outer join predicates.

• Added the  info_ schema_ show_ null_ dbs  engine variable that allows non-privileged users to view the rows in  *_ BOTTOMLESS_ *  information schema views where the associated database name is NULL.

• 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.

• Columns with extended types now use the correct default table collation.

• Enabled correlating fields in subselects to reference outer selects more than one level up.

• Enabled skipping of non-alterable tables from asynchronous DDL queries.

• The  bottomless_ plancache_ worker_ threads  engine variable can now be configured at runtime.

• Updated to use a consistent snapshot while performing a shallow table copy.

• Disabled segment elimination for IN clauses for which the left-hand expression is not a table column.

• Improved the error message returned when the invalid key is specified in the CONFIG/CREDENTIALS JSON.

• Improved the error message for parameter count mismatch during query parsing.

• Users with SHOW METADATA privilege can now access the  LOAD_ DATA_ ERRORS  information schema view.

• Added support for delimited batch sets in external functions.

• Added support for the LIMIT clause in prepared statements.

• Added the  disk_ plan_ gc_ pause_ seconds_ on_ startup  engine variable that disables disk plan garbage collection on startup.  This variable prevents hot plans from being unintentionally disk garbage collected.

• Computed column definitions now support the SPLIT function.

• Added the  scheduler_ slow_ threshold_ seconds  engine variable that specifies the threshold for triggering the verbose logging of scheduler thread timing.

• The DROP and ALTER TABLE commands no longer have to wait for the plan garbage collector.

• Added support for updated Standard and Enterprise licenses.

• Improved the garbage collection behavior for plancache.

• Introduced support for placeholders for partition ID and timestamp in the  SELECT INTO . . .  filename  command.

• Added the following engine variables:

  Note: Only use the following under the guidance of or as directed by SingleStore Support.

  • repl_ page_ desc_ limit_ before_ stall : Limits the number of page descriptors in the page map that a 'ReplLog' can use before stalling new transactions.

  • repl_ io_ buffer_ limit : Limits the number of IO buffers that a 'ReplLog' can use before stalling new transactions.

  • [dr_ ]repl_ network_ buffer_ size : Replication tries to set both send and receive buffer sizes to reduce waits on TCP ACK packets.  Can be set for both DR and non-DR replicas.

  • [dr_ ]repl_ max_ chunk_ size : When sending logs or snapshots to a replica, limit the chunk size to this value.

Bugfixes

• Fixed resource pool and workload management, CPU limiting.

• Fixed a locking bug related to table module eviction during recovery.

• Fixed a deadlock in a rare scenario related to low memory conditions.

• Fixed a rare race condition that caused a node to get stuck in offline mode after recovery.

• Fixed an issue that led to undefined behavior if a node failed concurrently with the computation of the replication distribution tree.

• Fixed a race condition that caused the autostats file to leak while reprovisioning.

• Fixed incorrect autostats in a rare failover case during asynchronous replication.

• Fixed a race condition in autostats between table refresh and table deletion.

• Fixed a race condition that could cause the shutdown to hang.

• Fixed a rare crash in synchronized variables initialization.

• Fixed a bug in the deadlock avoidance algorithm that could lead to deadlocks.

• Fixed a bug that caused nodes to crash when ALTER TABLE queries ignored foreign keys.

• Fixed a rare deadlock related to temporary tables.

• Fixed a crash in SHOW PROCESSLIST in a rare race condition scenario.

• Fixed a bug in CTE rewrites.

• Fixed a leak in a rare scenario.

• Fixed a bug in the parser.

• Fixed a crash in a shallow copy of a table with a pending ALTER operation.

• Fixed an issue where IN-list factorization did not work with newline characters around the IN-list.

Enhancements

• Added full-text pushdown optimization that works with any filter in the WHERE clause.

• Added a new metadata table to track FTS indexes eligible for merging.

• Added support for stopword  token_ filter  for custom analyzers for full-text version 2.

• Added new nori (Korean) analyzer customizations for full-text version 2.

• Added Korean language analyzer for full-text version 2.

Bugfixes

• Fixed a crash when a BM25 function in a subselect referenced a table in the outer select.

• Fixed a crash during replay when a table uses an FTS index with JSON options.

• Fixed a potential replay failure on a table that uses full-text version 2.

Enhancements

• Added the  VECTOR_ INDEX  information schema view, which shows the amount of memory and disk used by each vector index.

• Added a fallback mechanism so that when the engine detects that an indexed vector search followed by filters yields fewer than LIMIT rows, the engine falls back to a full table scan to ensure sufficient rows are produced.  The fallback mechanism can be disabled by setting the engine variable  vector_ index_ fallback_ non_ index_ scan  to FALSE.

• Extended the VECTOR_ SUM  aggregate function to support the VECTOR data type.

• Added a vector index cache to limit the amount of memory used by vector indexes.  Refer to Vector Indexing for details.

Enhancements

• Added support for the  PIPELINE <pipeline_ name>  clause to the SHOW PROFILE command which allows you to view profile information for the specified pipeline.

• Added a HEADER DETECTION ON/OFF clause to control inference from CSV files.  For more information, refer to Schema and Pipeline Inference.

• Added support for inferring Parquet files with the INFER PIPELINE command.  For more information, refer to Schema and Pipeline Inference.

• Added support for inferring Iceberg files with the INFER PIPELINE command.  For more information, refer to Schema and Pipeline Inference.

• Added SHOW CREATE LINK command that allows you to view the CREATE statement for the specified link.

• Added support for TIME(0), TIME(6), DATETIME(0), and DATETIME(6) types for the CAST command for use with computed columns and the SET clause for use with pipelines and LOAD DATA.

• Added the  CREATE_ USER  and  ALTER_ USER  columns to the PIPELINES information schema view.

• Added support to infer CSV files with a single column when the file contains no field terminators in any record.

Bugfixes

• Fixed an issue that caused an error if column names had trailing spaces in CREATE PIPELINE statements.

Enhancements

• Implemented support for automatically generated column mappings (for primitive data types and structures) as part of iceberg schema inference.

• Added support for EKS IRSA with assumeRole for Iceberg pipeline authorization.