# MariaDB 5.1.38 Changelog [Download](https://askmonty.org/wiki/MariaDB:Download:MariaDB_5.1.38) | [Release Notes](https://mariadb.com/docs/release-notes/community-server/old-releases/5.1/5.1.38) | **Changelog** |[Overview of 5.1](https://mariadb.com/docs/release-notes/community-server/old-releases/5.1/changes-improvements-in-mariadb-5-1) **Release date:** 29 Oct 2009 MariaDB-5.1.38-beta is based on MySQL-5.1.38, but has these additional changes\ and bug fixes: * mysql-test-run now has options `--stop-file` and `--stop-keep-alive` (also\ accessible with environment variables MTR\_STOP\_FILE and MTR\_STOP\_KEEP\_ALIVE).\ With these, it is possible to pause a running test temporarily and let it\ continue later. See [mysql-test-run](https://app.gitbook.com/s/SsmexDFPv2xG2OTyO5yV/clients-and-utilities/testing-tools/mariadb-test). * Improvements to Gcov support in testing. * New column [TIME\_MS in SHOW\ FULL PROCESSLIST and INFORMATION\_SCHEMA.PROCESSLIST](https://app.gitbook.com/s/SsmexDFPv2xG2OTyO5yV/reference/system-tables/information-schema/time_ms-column-in-information_schemaprocesslist), similar to the old\ TIME column, but with microsecond resolution. Also fixes old TIME column to\ not be influenced by @TIMESTAMP. Patch by Percona. * Optimizer improvement: Table elimination ([MWL#17](https://askmonty.org/worklog/?tid=17)). See [Table Elimination](https://app.gitbook.com/s/SsmexDFPv2xG2OTyO5yV/ha-and-performance/optimization-and-tuning/query-optimizations/table-elimination). * Enhancements to slow log. Includes details of execution plan and\ microsecond-precision resolution. Based on microslow patch by Percona. See [Slow Query Log Extended Statistics](https://app.gitbook.com/s/SsmexDFPv2xG2OTyO5yV/ha-and-performance/optimization-and-tuning/query-optimizations/statistics-for-optimizing-queries/slow-query-log-extended-statistics). * PBXT storage engine. PBXT is developed by [PrimeBase Technologies](https://www.primebase.org). * [XtraDB storage engine](https://app.gitbook.com/s/SsmexDFPv2xG2OTyO5yV/server-usage/storage-engines/innodb) version 6 as a replacement\ for the MySQL built-in InnoDB. XtraDB is based on the Oracle/Innobase InnoDB\ plugin version 1.0.3, with enhancements. XtraDB is developed by Percona. * Performance improvements for common cases of character set conversion. See [Character Sets and Collations](https://app.gitbook.com/s/SsmexDFPv2xG2OTyO5yV/reference/data-types/string-data-types/character-sets/supported-character-sets-and-collations) for a list of\ the character sets and collations included with MariaDB. * [Pool-of-threads](https://app.gitbook.com/s/SsmexDFPv2xG2OTyO5yV/ha-and-performance/optimization-and-tuning/buffers-caches-and-threads/thread-pool/thread-pool-in-mariadb-51-53), allowing to map a high number of simultaneous connections\ onto a lower number of operating system treads, to reduce overhead with using\ large number of threads. * New handler call prepare\_index\_scan() and other small improvements to the\ internal storage engine handler API. * ./configure now outputs a summary section at the end of the output. (By C.J.\ Adams-Collier). * NDB storage engine disabled in MariaDB builds. (NDB is not supported in\ MariaDB). * Added `--abort-source-on-error` to the [mysql\ client](https://app.gitbook.com/s/SsmexDFPv2xG2OTyO5yV/clients-and-utilities/mariadb-client/mysql-command-line-client). * [Faster CHECKSUM TABLE](https://app.gitbook.com/s/SsmexDFPv2xG2OTyO5yV/reference/sql-statements/table-statements/checksum-table). * Debugging code to check for taking mutexes in the wrong order, which enables\ to catch potential deadlocks in the server code. * [Maria](https://app.gitbook.com/s/SsmexDFPv2xG2OTyO5yV/server-usage/storage-engines/aria) storage engine. The Maria storage engine is an enhanment over the\ MyISAM storage engine which provides journaling and crash recovery. * Added new startup option and test commands to [mysqltest](https://app.gitbook.com/s/SsmexDFPv2xG2OTyO5yV/clients-and-utilities/testing-tools/mariadb-test). ## Bug Fixes * mysqlslap: setting `--engine` does not get replicated ([MySQL Bug #46967](https://bugs.mysql.com/bug.php?id=46967)). * mysqlslap: specifying `--engine` and `--create` does not work with`--engine=: