Parameter type: Integer
Default value: 64kB
Range: 32kB to system dependent
Minimum scope of effect: Cluster
When value changes take effect: Restart
Required authorization to activate: EPAS service account
The amount of memory used in shared memory for WAL data. Because the data is written out to disk at every transaction commit, the setting must be large enough only to hold the amount of WAL data generated by one typical transaction.
Increasing this parameter might cause EDB Postgres Advanced Server to request more System V shared memory than your operating system's default configuration allows. See Shared Memory and Semaphores in the PostgreSQL core documentation for information on how to adjust those parameters.
Although even this very small setting doesn't always cause a problem, in some situations it can result in extra
fsync calls and degrade overall system throughput. Increasing this value to about 1MB can address this problem. On very busy systems, you might need an even higher value, up to a maximum of about 16MB. Like
shared_buffers, this parameter increases EDB Postgres Advanced Server’s initial shared memory allocation. If increasing it causes an EDB Postgres Advanced Server start failure, increase the operating system limit.