wal_buffers

wal_buffers is the amount of shared memory used to stage write-ahead-log records before they are flushed to the WAL files. Bigger buffers reduce how often a transaction has to wait for WAL to be written, which helps write-heavy and highly-concurrent workloads.

The default (-1) auto-sizes it to 1/32 of shared_buffers, capped at 16 MB, which is fine for most systems. Very write-intensive workloads can benefit from 16–64 MB. It's allocated at startup, so changes need a restart.

Is 16 MB enough for wal_buffers?

For the large majority of workloads, yes — that's the auto-sized cap. Only very high-throughput, highly-concurrent write workloads tend to gain from raising it further.

• shared_buffers
• max_wal_size
• synchronous_commit