Write-ahead logging (WAL)

wikipedia:Write-ahead logging

• /var/lib/postgresql/##/main/pg_wal/
• wal_level: replica, minimal, logical

Prometheus logs:

• ts=2023-02-17T01:00:03.414Z caller=head.go:1011 level=info component=tsdb msg="WAL checkpoint complete" first=1633 last=1634 duration=628.31117ms

News

• 2024 PostgreSQL 17 - 2x better write throughput due to improvements with write-ahead log (WAL) processing

Errors

• could not find WAL segment
• 2023-06-19 06:32:37.504 UTC [1440100] HINT: Consider increasing the configuration parameter "max_wal_size".

Related terms

• Point-in-time recovery (PITR)
• ACID
• ARIES
• Amazon RDS Read Replicas
• Data warehouse: Change Data Capture (CDC)
• timescaledb-tune -wal-disk-size
• PostgreSQL, SQLite

See also

• WAL: wal_level, PostgreSQL, SQLite
• pg_dump, pg_dumpall, WAL, PITR, PgBackRest
• PostgreSQL replication, Amazon RDS Read Replicas, WAL, pg_replication_slots, START_REPLICATION, CREATE SUBSCRIPTION
• Point-in-time recovery (PITR)