mariadb – Türker Yıldırım

MariaDB 11.0 and a new optimizer cost model

NoteJuly 18, 20232 min read

The 11.0 release rewrites the cost constants, which is a change that improves most plans and changes some of yours. A cost model change is the kind of…

MariaDB 10.6 and the InnoDB that is no longer XtraDB

NoteJuly 15, 20211 min read

MariaDB replaced XtraDB with its own InnoDB fork some versions ago, and 10.6 is where the accumulated differences from MySQL stop being cosmetic. The two are no longer…

A report that was a loop, and the window function it became

Deep diveAugust 19, 202010 min read

380 MB of memory and a nightly job that could not be run on demand. Running totals and rankings needed a loop before window functions, and the loop…

A read replica that was silently stale

Deep diveJune 25, 202015 min read

The replica was up, accepting connections and serving data from an hour ago. Seconds_Behind_Master reported zero, honestly, and was measuring the wrong thing.

MariaDB 10.5 and the InnoDB that is no longer XtraDB

NoteApril 14, 20202 min read

10.5 in June replaced XtraDB with upstream InnoDB, which is a change to the storage engine that most upgrade notes describe as an implementation detail. Removed variables in…

An index that was never used, and the week it took to prove it

Deep diveNovember 8, 201910 min read

Forty indexes on one table and nobody willing to drop any of them. Invisible indexes turn a guess into a week of production traffic as evidence.

MariaDB 10.4 and the authentication change on upgrade

NoteFebruary 25, 20191 min read

10.4 changed the default authentication for the root account to unix_socket, so an upgrade produces a root that cannot log in with a password and a lot of…

MariaDB 10.3 system-versioned tables give you history free

NoteSeptember 2, 20182 min read

Keeping an audit trail normally means a trigger writing to a history table, which is code to maintain and a place for the two to drift apart. The…

Sequences in MariaDB, and where AUTO_INCREMENT falls short

NoteApril 12, 20181 min read

AUTO_INCREMENT belongs to a table and produces a value only on insert, so two tables cannot share a numbering space and nothing can reserve a block of ids…

Window functions replace a habit

Deep diveApril 2, 201815 min read

8.0 went GA in April and the correlated subquery can retire. The plans before and after, the recursive CTE that replaces a loop, and the upgrade nobody expects.