Notes for the problems that show up after launch: bad plans, awkward migrations, index debt, vacuum pressure, replica lag, and the small decisions that keep PostgreSQL, MySQL, MariaDB, and SQL Server easier to operate.
Find the queries dragging your Postgres down, read their plans, and fix them in order of impact.
Read the guide →Which indexes to add, which to drop, and how to spot redundant index debt before it costs you writes.
Read the guide →How autovacuum works, when it falls behind, and how to keep bloat from eating your storage and your buffer cache.
Read the guide →Sizing pools, PgBouncer modes, and how to stop idle-in-transaction sessions from exhausting max_connections.
Read the guide →Track lag, WAL throughput, and replication slots before they turn into stale reads or a full disk.
Read the guide →
Backups, restores, PITR, archive gaps, and recovery drills for PostgreSQL.
AWS RDS, Azure Database for PostgreSQL, Google Cloud SQL, AlloyDB, and managed PostgreSQL monitoring notes.
Connection storms, pool saturation, PgBouncer behavior, and max_connections pressure.
CPU, memory, disk, temp files, checkpoints, buffers, and workload pressure.
Index design, index debt, reindexing, constraint indexes, and evidence-driven DDL.
Lock waits, deadlocks, blocking chains, idle transactions, and transaction hygiene.
Galera clustering, InnoDB and Aria internals, replication, optimizer behavior, and MariaDB operations notes.
InnoDB internals, replication, locking, query performance, and MySQL operations notes.
HNSW, IVFFlat, recall, embedding search, and production RAG performance notes.
Replica lag, WAL growth, failover readiness, hot standby behavior, and replication slots.
Query plans, EXPLAIN ANALYZE, planner regressions, pagination, joins, and statistics.
Wait statistics, tempdb, Query Store, Always On availability groups, and SQL Server operations notes.
Autovacuum, dead tuples, bloat, wraparound, MVCC, freeze age, and visibility.
MySQL 8.x gives you a rich optimizer hint toolbox, and PostgreSQL deliberately refuses to. Here is what a PostgreSQL practitioner actually does instead: statistics, rewrites, planner GUCs, and pg_hint_plan as a genuine last resort.
MySQL's utf8 was never really UTF-8, and fixing it shaped a decade of schema decisions. Here is how PostgreSQL handles encoding and collation, and where migrations from utf8mb4 go wrong.
MySQL fakes booleans with TINYINT(1); PostgreSQL has the real thing. The migration is easy until an ORM mapping or a stray value of 2 makes it interesting. Here is the complete type-mapping story.
MySQL spent two decades tightening sql_mode; PostgreSQL shipped strict and stayed there. Here is what that history means for a migration: the queries that break, the data that will not load, and the bug classes that disappear.
When checkpoint age catches up with redo capacity, InnoDB stops the world to flush, and your p99 pays for it. Here is how innodb_redo_log_capacity works in 8.0.30+, how to size it against write bursts, and how furious flushing looks in…
GROUP BY, DISTINCT, derived tables, and window functions can all materialize internal temp tables, and when those overflow memory your query is suddenly doing disk I/O nobody planned. Here is how the TempTable engine works and how to find the…
InnoDB prevents phantoms by locking gaps; PostgreSQL prevents them with snapshots and serialization checks. Migrating between the two means retraining your instincts about blocking, deadlocks, and retries.
AUTO_INCREMENT and PostgreSQL identity columns solve the same problem with different machinery. This guide covers gaps, counter persistence, sequence caching, and the migration steps that actually bite.
One idle REPEATABLE READ session can pin millions of undo records and slowly melt a busy MySQL server. History list length is the canary; this is how to watch it, find the blocker, and keep undo growth under control.
Doublewrite exists for one narrow disaster: a torn page that redo cannot repair. This is an honest look at how it works, what it really costs in I/O, how to measure that overhead yourself, and when disabling it is actually…