SingleStore DB

Maintenance Release Changelog
2021-10-12 Version 7.5.12
  • Fixed an issue in the join optimizer that incorrectly eliminated candidate plans from the search.

  • Fixed a write amplification issue associated with row versioning. The behavior is disabled if the database is not unlimited storage.

  • Added support for MySQLDump 8.0.

  • Fixed a server startup failure when LD_PRELOAD is set. The behavior now reverts to a previous version which would overwrite any existing LD_PRELOAD setting.

  • 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.

  • Reduced the memory used to download blob files from remote storage.

  • Fixed a regression in recovery performance for databases using remote storage.

  • Fixed a crash that could occur when using LINK syntax with Avro pipelines.

  • Added Linux dependencies for SASL to SingleStore installation packages so they do not need to be installed separately.

2021-10-01 Version 7.5.11
  • Masked blob store CREDENTIALS text in CREATE DATABASE command for unlimited storage in SHOW PROCESSLIST, information_schema.PROCESSLIST, and all error messages.

2021-09-21 Version 7.5.10
  • Removed the 16384 size limit on the Avro array and map sizes in pipelines and LOAD DATA when pipelines aren't utilized.

  • Masked blob store CREDENTIALS text in BACKUP, RESTORE, and LINK commands in SHOW PROCESSLIST, information_schema.PROCESSLIST, and all error messages.

  • Increased incremental blob file streaming to disk to reduce memory overhead for unlimited storage.

  • Added support for incremental backups to utilize LINK syntax to specify CONFIG and CREDENTIALS clauses.

  • Added support for READ ONLY or READ WRITE syntax to the SET TRANSACTION statement for MySQL compatibility.

  • Added support for optimizing cases of IN joins in subselects in the project list.

  • 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.

  • Fixed auto histograms to determine when to build new histograms based on both master and child aggregators.

  • Fixed an aggregator crash that was caused when a malformed INIT_DB command is sent by a client.

  • Added support for complex joins (joins with non-linear/nested join tree) involving correlated nested SELECT queries.

  • Added an new engine variable named rewrite_verbose to output tracings of the rewrite phase on the current query in the tracelogs.

  • Fixed warning indicating "partition metadata is out of sync on table", which could appear in the tracelog after a node restart.

  • Added support for SKIP CONSTRAINT ERRORS options for Avro and JSON pipelines.

  • Increased the timeout used when connecting to AWS to determine credentials if none are specified in a BACKUP/RESTORE command.  Also added a new engine variable subprocess_ec2_metadata_timeout_ms which allows users to set that timeout.

2021-08-30 Version 7.5.9
  • New Feature: Added support for alias references in WHERE clauses and as column expressions. See SELECT for more information.

  • Fixed an issue where Disaster Recovery of a non-unlimited storage database was not blocked if a cluster was configured to use remote storage.

  • The AGGREGATOR SYNC AUTO_INCREMENT command now can be performed by anyone with the ability to update the target database(s) or table in any way.

  • Fixed an issue that could cause defunct processes for pipelines or code generation in a rare race condition.

  • Increased batch deletions from unlimited storage to improve the performance of GCing files from remote storage.

  • Improved JSON built-in functions to better handle out of memory errors.

  • Improved the cardinality estimates for columns with an equality predicate.

2021-08-16 Version 7.5.8
  • Fixed per-predicate PROFILE statistics on columnstore filter operations.

  • Fixed a crash that could occur when running CREATE PIPELINE or REPLACE PIPELINE on a pipeline that already exists.

  • Removed truncation of the query text in query.log when general_log=on.

  • 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).

2021-08-09 Version 7.5.7
  • New Feature: Added anonymous code blocks which are unnamed blocks of SingleStore (MemSQL) Procedural SQL (MPSQL) code that are executed immediately. They allow you to create a code block without defining and calling a stored procedure and are useful in situations such as testing or debugging.

  • 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.

  • 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.

  • Improved usability of various JSON-builtins to support utf8mb4 charset arguments.

  • Increased frequency of merging during load for unique keys on columnstores.

  • Added information_schema.mv_bt which shows backtrace information for all nodes in the cluster.

  • Added information_schema.mv_plancache which shows plancache information for all nodes in the cluster (cluster-wide version of information_schema.plancache).

  • Added support for the transaction_read_only and tx_read_only session variables for MySQL compatible client drivers that query them.

  • Fixed a performance regression establishing SSL connections introduced in 7.5.

  • Fixed a deadlock which can occur if a failover happens during an ALTER TABLE.

  • Changed the SET PASSWORD statement to query forward from the child aggregator to the master aggregator.

2021-07-20 Version 7.5.6
  • Initial GA release of version 7.5.5

2021-07-07 Version 7.5.5
  • Stability improvements to version 7.5.4

2021-06-28 Version 7.5.4
  • Fixed an "invalid LSN" error when restoring a local storage database into a remote storage database.

2021-06-24 Version 7.5.3
  • Fixed an issue that could cause DETACH DATABASE to hang while a pipeline that is attempting to load batches is failing.

  • Fixed an issue that could generate incorrect out of memory errors when using a remote storage database.

2021-06-22 Version 7.5.2
  • Beta release of SingleStore DB 7.5