Monday, July 24, 2017

How far can you go with MySQL or MariaDB ?

MySQL theoretical limits are known and they can be found in the manual, they include:
But what can be done in practice ?  How far can you go with MySQL or with MariaDB ?

Those questions were raised while discussing with a colleague doing Professional Services and Consulting on MySQL.  He was reporting hearing too often unjustified statements like "MySQL surely cannot store that much data" for some big amount of "that much".  I told him that I would share some numbers on the big deployments I know about.  Here they are with some things to consider when managing such large deployments.

Wednesday, July 19, 2017

InnoDB Basics - Compaction: when and when not

This is old news for MySQL/MariaDB expert but people that are starting using InnoDB do not always know that disk space is not automatically released when deleting data from a table.  To explain and demonstrate that, I will take two real-world examples: table1 and table2.

Wednesday, July 5, 2017

Fun with InnoDB Persistent Statistics

Something interesting happened to me in the last days, and it is worth sharing.  I was upgrading MariaDB (MySQL also impacted) to a new major version and mysql_upgrade showed something like this:
[...]
Phase 4/7: Running 'mysql_fix_privilege_tables'
ERROR 1062 (23000) at line 586: Duplicate entry 'schema-table_name#P#partition_name_truncated' for key 'PRIMARY'
ERROR 1062 (23000) at line 590: Duplicate entry 'schema-table_name#P#partition_name_truncated' for key 'PRIMARY'
ERROR 1062 (23000) at line 593: Duplicate entry 'schema-table_name#P#partition_name_truncated' for key 'PRIMARY'
FATAL ERROR: Upgrade failed