Parameter · Preset Options
wal_block_size
Shows the block size in the write ahead log.
- Default:
8192 - Type: integer
- Range: 8192 … 8192
- Applies: Read-only
In plain words
WAL files are written in pages too. This is their size, normally 8 kB, the same as data pages.
For DBAs and operators
Set with configure --with-wal-blocksize; changing it needs a new build and initdb. Each WAL page starts with a small header; records can span pages. It is the unit for wal_buffers (shown as 8kB pages) and the reason WAL writes are aligned to 8 kB. Tools such as pg_waldump and backup software assume the server and tool were built with the same value.
How to change it
Fixed when PostgreSQL was built or the cluster was initialised. You can only read it.