Database Topic Archive
Galera clustering, InnoDB and Aria internals, replication, optimizer behavior, and MariaDB operations notes.
Finance needed last night's nginx logs joined against orders, and someone remembered the CONNECT engine could read a CSV as a table. It worked beautifully for three weeks — until logrotate moved the file mid-query and every report died with…
Monday 09:00, the entire application tier was locked out: 'Host 10.0.4.17 is blocked because of many connection errors; unblock with mysqladmin flush-hosts'. A new Kubernetes liveness probe had spent the weekend opening TCP connections and closing them without a handshake.
Rotate MariaDB TLS files with FLUSH SSL, distribute trusted CAs first, and verify new client connections, account certificate requirements, and replicas.
The nightly loader survived four MariaDB upgrades and died on the fifth with 'Incorrect integer value'. The default sql_mode had quietly changed in 10.2.4, and this one legacy box had skipped straight past the release where the warning would have…
We turned on server_audit with QUERY events on a Friday, logged 41 GB over the weekend, filled the disk, and added 30% to write-path p99. The compliant configuration we ended up with logs 2 GB a day and nobody notices…
Our order numbers lived on AUTO_INCREMENT until a second write node appeared and the increment-and-offset trick started to creak. Sequences gave us controlled, cacheable, gap-tolerant numbers — here is the full cost sheet.
The telemetry table had monthly partitions plus a MAXVALUE catch-all, and a cron job that added next month's partition — until the cron host was decommissioned and nobody noticed for eleven months. 900 million rows sat in pmax, and REORGANIZE…
One reporting replica pulled from three primaries for eight months without a hiccup — until the catalog primary failed over and the replica started applying the same transactions twice. Every server involved shared gtid_domain_id 0. Here is the full autopsy.
MariaDB 10.6 goes end of life in July 2026, so we rehearsed the jump to 11.4 LTS on a restored backup. The upgrade itself took eleven minutes; finding the removed config variable, the renamed client tools, and the one query…
Users updated their profiles, hit save, reloaded — and saw the old values. The write went to Galera node A, the read to node B, and node B had not applied the writeset yet. wsrep_sync_wait was 0, the default. The…