Release Notes for MariaDB Xpand 5.3.11-rc

MariaDB Xpand is a distributed storage engine. Xpand provides High Availability (HA), full ACID compliance, and fault tolerance with scale-out and elasticity. Through Xpand, MariaDB Enterprise Server harnesses the power of distributed SQL, with data distributed across Xpand nodes and queries executed across Xpand nodes as needed to produce a result set.

MariaDB Xpand 5.3.11-rc is included with MariaDB Enterprise Server 10.5.5-3. This release of Xpand is release candidate maturity, and is not recommended for production use. This release follows Xpand 9.3-beta-7, reflecting a change in numbering. Subsequent releases in the Xpand 5.3 series will focus on stability and reliability.

MariaDB Xpand 5.3.11-rc was released on 2020-09-08.

Notable Changes

  • Added options for binlog statements for Xpand tables not to be written to the binlog as consistency cannot be guaranteed when multiple sources are used to write to Xpand. In case there is only one MariaDB Server serving as a frontend to the Xpand backend current behavior can be used. In order to use Xpand with multiple frontends, set the following options on all frontends that are being written to --xpand-master-skip-dml-binlog=TRUE and --xpand_replicate_alter_as_create_select variables+TRUE. Note that in a replication setup the MariaDB Servers acting as replicas (receiving binlog events from masters) should also set the following variables: --slave_ddl_exec_mode=STRICT and --xpand-slave-ignore-ddl=TRUE (MENT-906)

  • system.sessions table updated to contain more information about ongoing Xpand sessions. (CLX-407)

  • Fixed an issue where the Xpand backend password was visible to all users through a system variable. (CLX-421)

Bugs Fixed

Can result in data loss

  • Upper limit of UNSIGNED INT was lower than the actual limit. (CLX-217)

  • In some cases INSERT INTO .. SELECT .. FROM .. ON DUPLICATE KEY UPDATE could lead to table corruption in Xpand. (CLX-467) (CLX-, 452)

Can result in hang or crash

  • Rollback of transactions due to errors can in rare cases crash MariaDB Server. (CLX-73)

  • ANALYZE TABLE on an Xpand table can cause a crash. (CLX-163)

  • Hitting the lock_wait_timeout time can be reported as a crash instead of being reported as exceeding the lock wait timeout time. (CLX-344)

Can result in unexpected behavior

  • MariaDB Server prevented from starting with Xpand tables present if the Xpand backend could not be reached. Now the server will start, however it will report errors when trying to use Xpand tables if the Xpand backend cannot be reached. (CLX-75)

  • Table names can be pushed down to the engine backend in an incorrect format resulting in an unknown table name error or other related errors. (CLX-429) (CLX-241)

  • Indexes are not always used correctly when multiple indexes have been defined on the same table after the creation of the table. (CLX-229)

  • Table definition is not properly updated on other MariaDB Servers connected to the same Xpand backend if they were in a shutdown state when the table definition was updated on one of them. (CLX-384)

  • Operation not permitted error can be reported when doing a SELECT with a WHERE condition with multiple AND and OR operators. (CLX-389)

  • Deadlock detection in the Xpand engine is not always enforced. (CLX-409)

  • Auto_increment information was missing from SHOW CREATE TABLE in some cases for Xpand tables. (CLX-387)