wal_log_hints

A GUC parameter determining whether the entire content of each disk page is written to WAL during the first modification of that page after a checkpoint

wal_log_hints is a GUC parameter determining whether the entire content of each disk page is written to WAL during the first modification of that page after a checkpoint.

wal_log_hints was added in PostgreSQL 9.4.

Default value

The default value for wal_log_hints is: off

Usage

wal_log_hints has the same performance impact as enabling data page checksums. As the latter can only be enabled when a cluster is set up with initdb, it provides a way of testing for performance impacts without setting up a new cluster.

If pg_rewind is intended to be used, and data page checksums are not enabled, wal_log_hints must be set to on.

The current value of wal_log_hints is one of the GUC configuration parameters recorded in pg_control.

Change history

Categories

GUC configuration item, Replication, WAL

See also

wal_level