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.
Row counts are not proof. This post covers cross-engine checksums, the collation, float, and timezone traps that make MySQL and PostgreSQL disagree, and how to build reconciliation jobs.
SHOW PROCESSLIST is the first thing everyone runs and the most misread output in MySQL operations. Here is what the thread states actually mean, which pileups matter, and how to build a triage habit around performance_schema.threads.
MySQL's default is one thread per connection, and it degrades gracefully until it falls off a cliff. When the thread pool plugin actually helps, when it just rearranges the queue, and how to size max_connections without guessing.
TempTable spills have three stages and two ceilings, and the classic monitoring ratio is blind to the middle one. Here is how temptable_max_ram and temptable_max_mmap really work, and how to see spills.
ibtmp1 grows to its high-water mark and holds it until you restart MySQL, and one ambitious report query can inflate it past 100 GB. How the two temp tablespace kinds differ, how to cap them, and how to name the…
The sys schema ships with every MySQL 8.x server and most teams never open it. These are the five views I actually use every day - statement_analysis, the index-hygiene pair, file I/O, and host_summary - with the caveats that keep…
Stored procedures are the part of a MySQL migration nothing automates. Field notes on porting routines and triggers to PL/pgSQL, and on deciding which logic belongs in the app instead.
MySQL leans on the slow query log and performance_schema digests; PostgreSQL leans on pg_stat_statements and auto_explain. Here is how the workflows map, and where each side needs supplementing.
Semi-synchronous replication promises that a commit is acknowledged by at least one replica before the client sees success. The fine print — silent fallback to async, wait points, and what an ack actually means — is where production incidents live.
Every worker hammering the same first pending row is why your InnoDB job queue serializes. SKIP LOCKED fixes the claim path, if the index, the isolation level, and the row lifecycle are right.