# Maintenance Release Changelog

## 2022-10-17 Version 7.3.27

* Removed ability to use `utf8_general_mysql500_ci collation`. This collation is not supported by SingleStore .
* Improved the `Subselect To Join` rewrite to recognize more cases with subselects in filter conditions for left join.
* Fixed an issue that may cause `insert into mv_queries` to become invalid when the cluster is in `ONLY_FULL_GROUP_BY sql_mode`.
* Allow `REVOKE` from `ROLE` permissions for tables that have been dropped.

## 2022-07-05 Version 7.3.26

* Fixed an issue where the incorrect backup size showed in `mv_backup_history` for incremental backups.
* Fixed a potential issue with transaction rolled back-mid query errors that may occur when a database name has a number suffix.
* Fixed issues with the `information_schema.mv_activities` and `information_schema.mv_activities_extended` tables reporting incorrect activities on database names ending with an integer.
* Fixed a server crash caused by serializing big table or view definitions in snapshots.
* Fixed an issue when running `DROP TABLE` on a function instead of `DROP FUNCTION`.
* Fixed a server crash caused by a rewrite trying to inline nested expressions.
* Fixed an issue with out of memory errors being generated while compiling queries that use multiple `UNION` clauses.
* Adjusted the maximum memory allocation function to proactively run even when the `total_server_memory` usage is well below the `maximum_memory` allocation.
* Fixed an issue with error generation for aggregator result tables used in a parallel read. `DROP RESULT TABLE` now returns the correct error.

## 2022-04-11 Version 7.3.25

* Improved heuristic estimates for queries with complex join predicates.
* Reduced the amount of stack space required to perform code generation for large in-lists.
* Fixed an issue where table-valued functions crashed when a parameter was used more than once while compiling a query.
* Improved the performance of sampling queries executed by the query optimizer.

## 2022-02-23 Version 7.3.24

* Fixed an issue with query forwarding incorrectly triggering aggregator sync causing the aggregators to run out of disk space.
* Fixed an issue with incorrect `nullCount` and `rowCount` statistics for larger tables with autostats enabled.
* Fixed an issue with `memsql_exporter` ceasing to produce monitoring results.

## 2022-01-31 Version 7.3.23

* Fixed a cluster database log corruption that could occur if the root user was dropped when the `sync_permissions` global variable was enabled.
* Fixed the `CLEAR ORPHAN DATABASES` command to ensure all databases are dropped when the `leaf_failover_fanout` global variable is set to `load_balanced` and there are partition databases with more than replica partition.
* Fixed a bug that incorrectly pushes a join before a window function when attempting to perform a distributed join in an aggregator.

## 2022-01-10 Version 7.3.22

* Improved the predicate transitivity rewrite during query execution to cover more cases in an `EXISTS/NOT EXISTS` clause.
* Reduce probability of failed connections to clusters due to WebSockets proxy issues.
* Fixed the calculation for `total_runtime_ms` for queries profiled from within stored procedures. Prior to this release, `total_runtime_ms` was not calculated accurately.

## 2021/12/13 Version 7.3.21

* Fixed the default value for `max_async_compilation_concurrency` so that it is now set appropriately when [control groups](https://en.wikipedia.org/wiki/Cgroups) are in use limiting CPU usage.
* Added [control group](https://en.wikipedia.org/wiki/Cgroups) awareness for `information_schema.mv_nodes` which now displays the correct number of CPUs a process has access to.
* Fixed an issue with a crash occurring when an incremental backup was performed on an empty database.
* Fixed an issue with a crash occurring when DDL is run inside a stored procedure that is executed within a resource pool on a child aggregator.
* Block the `DROP TEMPORARY TABLE` command from running in a transaction that writes to the temporary table being dropped. The `DROP TEMPORARY TABLE` command result will display an error.
* Clarified error messaging when invalid data is inserted into a utf8 charset data type column.

## 2021/11/08 Version 7.3.20

* Added support for `BACKUP DATABASE` into S3 buckets using the `sts_regional_endpoints` configuration option.
* Fixed issue with crash occurring when attempting to compile queries for `UPDATE` statements with multiple columns due to insufficient memory resources. The amount of memory necessary to compile these query shapes was reduced.
* Fixed sync timeout errors occurring when `REBALANCE PARTITIONS` of large databases is being processed. The `REBALANCE PARTITIONS` operation now waits for the replication of large snapshot files. 
* Added `password_expiration` column to `information_schema.USERS` table. If the `password_expiration_seconds` engine variable is not enabled, the `password_expiration` column will be NULL. If the `password_expiration_seconds` engine variable is enabled, the `password_expiration` column will display the number of seconds remaining for the password to expire.
* Updated time zone data for some countries that recently changed their time zone rules.
* Added Linux dependencies for SASL to SingleStore installation packages so they do not need to be installed separately.

## 2021/10/18 Version 7.3.19

* Fixed an issue with possible connection crashes on disaster recovery clusters when DDL queries are forwarded to the master aggregator and a database has not been selected.
* Fixed an issue with table-valued functions crashing when the parameters used contain full-text match functions and window functions.
* Added support for running `PROFILE` on queries that execute inside of transactions the include multiple statements.
* Fixed a crash caused by a check on the maximum number of partitions allowed on a leaf node. An error message is displayed when this threshold is exceeded.
* Fixed an issue where the `memsql_exporter` would sometimes produce invalid JSON errors. The `memsql_exporter` is a satellite process that collects data about a running cluster.

## 2021/09/27 Version 7.3.18

* Added support for `SKIP CONSTRAINT ERRORS` options for Avro and JSON pipelines.
* Increased the timeout for fetching AWS credentials when none are specified for the `BACKUP` or `RESTORE` commands. Added a new engine variable, `subprocess_ec2_metadata_timeout_ms`, which allows users to set this timeout. Refer to [Sync Variables Lists](https://docs.singlestore.com/db/v9.1/reference/configuration-reference/engine-variables/list-of-engine-variables/#sync-variables-lists.md) for more information.
* Fixed auto histograms to determine when to build new histograms based on both master and child aggregators.
* Masked blob store `CREDENTIALS` text in `BACKUP`, `RESTORE`, and `LINK` commands in `SHOW PROCESSLIST`, `information_schema.PROCESSLIST`, and all error messages.
* Added support for incremental backups to utilize `LINK` syntax to specify `CONFIG` and `CREDENTIALS` clauses.
* Added support for optimizing cases of `IN` joins in subselects in the project list.
* Replaced the symlink from `/opt/memsql` to `/etc/systemdb/system/memsql.service` with copying the `memsql.service` file to avoid issues with some filesystems not being mounted.
* Removed the 20 second limit when checking for expired query plan at the `disk_plan_expiration_minutes` intervals.

## 2021/09/07 Version 7.3.17

* Fixed an issue that could cause pipelines to hang when encountering errors.
* Added session variable named `subquery_merge_with_outer_joins` that fine-tunes the behavior of the rewrite `SubQueryMerge`. If the variable is set to ON: always merge the sub-select with outer join(s). If the variable is set to HEURISTIC: check to see if merging the sub-select with outer join(s) will cause negative performance for the overall query. If the variable is set to OFF: don’t merge sub-selects with outer join(s). If the variable is set to AUTO (this is the default): For SingleStore 7.5 and previous versions, AUTO will behave like ON. For SingleStore versions after 7.5, AUTO will behave like HEURISTIC.
* Added support for complex joins (joins with non-linear/nested join tree) involving correlated nested `SELECT` queries.
* Fixed an issue with query failures occurring if `leaf_pushdown=1` hint is set. The query will be run without the hint and a plan warning will be emitted.
* Fixed an aggregator crash that was caused when a malformed `INIT_DB` command is sent by a client.

## 2021/08/23 Version 7.3.16

* Added [anonymous code blocks](https://docs.singlestore.com/db/v9.1/reference/sql-reference/procedural-sql-reference/anonymous-code-blocks.md) which are unnamed blocks of SingleStore Procedural SQL (MSQL) code that is executed immediately. They allow you to create a code block without defining and calling a stored procedure. They are useful in situations such as testing and debugging.
* Fixed a crash that could occur when `ALTER TABLE COMPRESSION=SPARSE` is run in the same `ALTER` statement with an operation that doesn’t require data movement (ie., `AUTOSTATS_ENABLED = ON)`.
* Fixed the cardinality estimates for columns with an equality predicate.
* Fixed a crash that can occur when a named window clause is used in multiple window functions in a query.
* Added a new system variable called `master_promote_kill_timeout_seconds` which specifies how long an online failover will wait to drain open write transactions before issuing a kill to those transactions. It is limited to 120 seconds. After the write transactions are killed, an application-level retry is required.
* Fixed an issue that can cause defunct processes for pipelines or code generation in a rare race condition.
* Updated `memsqlctl start-node` to check the validity of NUMA configurations when nodes are restarted. If the system doesn’t have NUMA configurations, the nodes will be restarted. If any of the nodes have invalid NUMA configurations, the NUMA bindings will be recalculated for all the nodes on the host.
* Fixed an issue that could cause backups to GCS to fail with the error "The difference between the request time and the server's time is too large".

## 2021/08/02 Version 7.3.15

* Added a new system variable called `parametrizer_query_max_params` which allows users to set the maximum number of scalar constants a single query can contain. Any query with more than `parametrizer_query_max_params` will be failed with an error. The default value is `1048576`.

## 2021/07/26 Version 7.3.14

* Updated `memsqlctl` to establish an SSL connection to the node if a CA certificate is set explicitly. SingleStore now falls back to an SSL connection via the host's default certificates if the target user requires SSL.
* Fixed an issue where the exporter process was not being cleaned up when `memsqld` is shut down.
* Fixed an issue where modifying the case of a column via `ALTER TABLE` could cause a pipeline using that table to crash.
* Fixed an issue where DDL forwarding could crash when `DROP USER` is run.

## 2021/07/12 Version 7.3.13

* Properly set keep alive and timeouts on the persistent leaf-to-master aggregator connection that is used to communicate replication link status. This fixes an issue with REBALANCE commands that failed with synchronization timeouts.
* Fixed a synchronization bottleneck, improving the ability of the pipeline scheduler to run many pipelines in parallel.
* Improved the performance of pipeline and database DDL actions when a database has many pipelines running.
* Fixed a blocking issue that could occur when several pipelines are being background scheduled simultaneously.
* Fixed an issue where incorrect results could be returned when using `INSERT_ALL` to insert into a temporary table.
* Fixed an issue that disabled a compilation optimization for selected queries. Disabling this optimization made certain queries slower.
* Fixed an issue that could cause the internal statistics tracked by workload management to become incorrect after a "too many queued" query error has been hit.
* Fixed an issue with CTE predicate pushdown where predicates were incorrectly split across `HAVING` and `WHERE` commands.

## 2021/06/21 Version 7.3.12

* Fixed a rare race condition that could cause sync replication to get stuck.
* Added a new system variable `optimizer_disable_subselect_to_join`. Setting this to `ON` disables the optimizer rewrite that converts subselect to joins automatically.

  Disabling this rewrite may cause queries to fail if they require the rewrite to run.
* Fixed an issue where a crash could occur when `data_conversion_compatibility_level` is set to a value other than `6.0` and a computed column is set to an invalid value via an `UPDATE` statement.
* Fixed an issue where a crash could occur when `leaf_failover_fanout` is set to `load_balanced` mode and `REMOVE LEAF` is run on larger clusters.
* Fixed an issue where a crash could occur when running `UPDATE` on a query with a scalar subselect in a `SET` clause after `ALTER TABLE`.
* Fixed an issue where in some rare cases `PROFILE` queries could cause a crash.
* Fixed an issue where `ROWSTORE_PROGRESS` could exceed 100% in `mv_backup_status`.

## 2021/06/01 Version 7.3.11

* Added a new system variable `auditlog_retention_period` which controls the retention period (in days) of audit log files on disk. The default is `0` which means files remain on disk indefinitely.
* `ADMIN_ONLY` audit log level now audits DDL statements only. Previously it would audit other non-DDL statements, which could cause bloat in the audit logs in `ADMIN_ONLY` mode.
* Fixed an issue where a crash could occur during concurrent columnstore `DELETE`s while escalating from row level locking to table level locking.
* Fixed an issue in universal storage unique keys where hash collisions with null values could produce incorrect results.
* Fixed an issue where incorrect results could be returned when using `UNION ALL` and `SELECT ... INTO S3`.

## 2021-05-24 Version 7.3.10

* Optimized partition placements when rebalancing partitions in `load_balanced` mode.
* Fixed a permissions error where the stated required permission was incorrect.
* Fixed reader quota errors that could be encountered by `DELETE` queries with limits that run distributed joins on derived tables.
* Fixed an issue where `CREATE GLOBAL TEMPORARY TABLE LIKE ...` would create a normal user table instead of a global temporary table.
* Fixed an issue with `DATETIME` equality testing when updating columnstore tables.

## 2021-05-03 Version 7.3.9

* Added support for temporary stored procedures. For more information, see [CREATE TEMPORARY PROCEDURE](https://docs.singlestore.com/db/v9.1/reference/sql-reference/procedural-sql-reference/create-or-replace-temporary-procedure.md).
* Added support for bloom filters on right joins using columnstore indexes and segment elimination. Previously, [bloom filters](https://docs.singlestore.com/db/v9.1/query-data/query-plan-operations.md) were only supported on inner joins.

## 2021-04-19 Version 7.3.8

* Added a new engine variable, `backup_max_threads`, which controls the number of concurrent threads used to run backups on leaves. By default, each backup uses one thread per partition. For more information, see [Non-Sync Variables List](https://docs.singlestore.com/db/v9.1/reference/configuration-reference/engine-variables/list-of-engine-variables/#non-sync-variables-list.md).
* Fixed an issue where queries filtering on the `transaction_state` column of `information_schema.PROCESSLIST` or `information_schema.MV_PROCESSLIST` could return the wrong results.
* Fixed a wrong results issue that could occur during online upgrade to version 7.3.
* Fixed a crash that could occur when using a table reference like \`table\_name.\*\` inside [TO\_JSON](https://docs.singlestore.com/db/v9.1/reference/sql-reference/json-functions/to-json.md)
* Fixed a bug on the websocket proxy where a connection could hang on the client after being killed on the server.

## 2021-04-01 Version 7.3.7

* Fixed a crash that could occur when a query included [user defined variables](https://docs.singlestore.com/db/v9.1/reference/sql-reference/user-defined-variables.md).

## 2021-03-15 Version 7.3.6

* Running DDL inside of stored procedures from child aggregators is now properly supported.
* Fixed a crash that previously occurred in cases where `SHOW CLUSTER STATUS` was run while a leaf node was unresponsive.
* Fixed an issue that caused incorrect tracing to the error log when `SHOW WORKLOAD MANAGEMENT STATUS` was executed.
* Fixed an issue with the system variable `redundancy_level` being incorrectly set on leaf nodes, which previously caused errors when `CHECK BLOB CHECKSUM WITH REPAIR` was run.
* Monitoring clusters are now supported via SSL.
* Fixed an issue that previously caused an incorrect error when running `LOAD DATA` from inside a stored procedure.

## 2021-03-08 Version 7.3.5

* `REBALANCE ALL DATABASES` and RE`BALANCE PARTITIONS FULL` now fully rebalance redundancy 1 clusters.
* Added support for connecting to[ Avro Confluent Schema Registry](https://docs.singlestore.com/db/v9.1/load-data/load-data-from-files/load-data-from-avro-files/avro-schema-evolution-with-pipelines.md), by specifying SSL configuration settings in `CREATE PIPELINE`.
* Fixed an issue with automatic histograms on clusters that were upgraded with the variable `cardinality_estimation_level` set to `6.0`.

## 2021-03-01 Version 7.3.4

* Fixed an issue that occurred when running `ALTER` or `TRUNCATE` against a table that included `ON DUPLICATE KEY UPDATE` in its `CREATE PIPELINE` statement.
* Fixed an issue that caused read actions on columnstore JSON objects to result in an error (`Error reading from parquet: Column not found in schema`) in cases where trailing whitespaces were present in the JSON key names stored for a given table.
* Improved the optimizer’s cost estimates for hash joins when one of the tables in a given join has an index matching the join condition.
* When inserting into a columnstore table, columns not needed to deal with a duplicate key are no longer decompressed.
* Fixed a crash that occurred when an aggregate function was used in an unsupported context inside a stored procedure.
* Added a new engine variable `optimizer_empty_tables_limit`, which sets a threshold for the number of empty tables that must be present in a query before the optimizer falls back to being rule based, instead of cost based. For more information, see [Sync Variables Lists](https://docs.singlestore.com/db/v9.1/reference/configuration-reference/engine-variables/list-of-engine-variables/#sync-variables-lists-2.md).
* When running `memsql_exporter`, the password for the monitoring user is no longer exposed in the `ps` output.
* Allowed `memsqlctl` to establish a secure connection when a node is configured for SSL using either the engine variable `ssl_ca`, or the host system’s trusted certificates for verification.
* Increased `TasksMax` to 128000 for `memsql.service` in order to prevent errors and/or unexpected node behavior. Previously, this setting was often exceeded, causing `systemd` to limit the ability of `memsqld` to fork processes.
* Fixed an issue that caused `auto-rebalance` operations occuring when `leaf_failover_fanout` is set to `load_balanced` not to fully rebalance the cluster.
* Updated the Websocket Proxy to respect the [engine variables](https://docs.singlestore.com/db/v9.1/reference/configuration-reference/engine-variables/list-of-engine-variables/#non-sync-variables-list-2.md), `ssl_cipher` and `tls_version`, in configuring `TLS` for external communication via `https`.

## 2021-01-19 Version 7.3.3

* Fixed a timeout error that occurred when running `REBALANCE PARTITIONS` on databases with large columnstore tables.
* Improved the speed of server shutdown and of recovery for databases with large numbers of tables. This improvement is evident at 1,000 tables or more, and increases significantly after 10,000 tables.
* Fixed an issue that caused `RESTORE` commands to fail in cases where a database contained a large number of reference tables.
* Fixed an issue that caused `DROP TEMPORARY TABLE IF NOT EXISTS` to incorrectly return an error in cases where the table didn’t exist.
* Fixed a crash caused by a check on the maximum number of partitions allowed on a leaf node. Now, an error message is surfaced when this is exceeded.
* Fixed issue that caused an error (`Transaction rolled back mid-query`) to occur when running cross-database queries in multi-statement transactions.
* Reduced blocks on `UPDATE` and `DELETE` commands via `background merger`.
* Added a new variable, `default_columnstore_table_lock_threshold`, which sets a threshold for the number of rows that are locked when updating rows in a columnstore table before a table lock is acquired. For more information, see [Sync Variables Lists](https://docs.singlestore.com/db/v9.1/reference/configuration-reference/engine-variables/list-of-engine-variables/#sync-variables-lists-3.md).

## 2020-12-15 Version 7.3

* Initial GA release of SingleStore 7.3.2

***

Modified at: November 26, 2025

Source: [/db/v9.1/release-notes/singlestore-memsql/7-3-release-notes/maintenance-release-changelog/](https://docs.singlestore.com/db/v9.1/release-notes/singlestore-memsql/7-3-release-notes/maintenance-release-changelog/)

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