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.
Our Sunday full backup of a 2.4 TB cluster had stretched to nine hours and the object-storage bill looked like a second salary. PostgreSQL 17's native incremental backup cut the weeknight run to about 95 GB — but the first…
A customer named José — or rather José, which is how his name had been stored for two years — finally filed the ticket that started our utf8mb4 migration. Then the first ALTER failed with ERROR 1071 because a 255-character…
We added two audit columns as INVISIBLE so nothing would see them until the rollout finished. Nothing saw them — including the nightly loader, which died at 02:40 with ERROR 1136 because its INSERT listed no column names, and the…
The primary ran out of disk at 04:12 on a Saturday: 340 GB of binary logs, accumulating since a migration eleven months earlier, on a server where expire_logs_days had never been set. Then the cleanup broke a replica nobody remembered…
A one-line ALTER to widen a VARCHAR queued behind a long analytics transaction — and because metadata locks queue fairly, every new query on the table stacked up behind the ALTER. The whole application hung on a schema change that…
The vendor stored procedure picked a terrible plan the night after a statistics update, and the support contract forbade touching the code. A plan guide pinned the good plan in twenty minutes without a single line of application change. How…
The monitoring tool showed Page Splits/sec at four hundred and the team wanted to rebuild every index in the database. The counter was counting end-of-index page allocations that cost nothing, while the real damage — mid-index splits on a random…
A well-meaning ad-hoc log backup broke the shipping chain at 14:00 on a Friday, and the monitor's alert threshold was set so loose that nobody noticed until the secondary was nineteen hours stale. Log shipping is the oldest DR trick…
The wait-stats report showed CXPACKET at 61 percent of all waits, so a well-meaning change set server MAXDOP to 1. The big report queries went from forty seconds to nine minutes overnight, and the actual problem — one missing index…
The availability group failed over in nine seconds. The applications stayed down for six minutes. The listener's DNS record was still pointing at the old primary's IP, the connection strings lacked MultiSubnetFailover, and every client was happily waiting out a…