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.
innodb_dedicated_server sizes your buffer pool and redo from detected hardware. On a truly dedicated box it is right; inside a memory-limited container it can size you straight into an OOM kill.
Checksum failures in the error log, a server that crashes 40 seconds after every start, and the six levels of innodb_force_recovery. What each level really skips, the dump-and-rebuild runbook, and why replicas beat recovery.
Mode 0 holds a table lock to the end of every insert, mode 1 only for bulk loads, mode 2 never. Why 8.0 defaults to 2, what that does to statement-based replication, and how to stop fearing ID gaps.
MySQL 8.0 replaced block nested loop with a real hash join, and half the join-tuning advice from the 5.7 era is now wrong. When the optimizer hashes, when an index beats it, and when it loses.
GTIDs make MySQL failover repointing almost trivial; replication slots make PostgreSQL WAL retention automatic but risky. A practitioner's comparison of the two position-tracking models.
An errant transaction is a write that exists on a replica but not on the source, and it sits harmlessly in gtid_executed until the exact moment you fail over. Here is how they happen, how to find them, and how…
Group Replication promises consensus-backed failover; classic async promises simplicity. Field notes on what GR actually guarantees, how flow control stalls write bursts, and when async plus an orchestrator is still the better architecture.
On a binlog-enabled MySQL server, every durable InnoDB commit is written to two logs and synced to storage at least twice. Here is how binlog group commit amortizes that cost, what the 1,1 settings really guarantee versus 2,0, and where…
PK-less InnoDB tables silently tax replication and tooling. GIPK mode fixes them at CREATE TABLE time, if you know what my_row_id changes and what it quietly breaks.
Two sessions inserting different rows can still deadlock under REPEATABLE READ. Gap locks, next-key locks, insert intention locks, and how to read the deadlock report.