A server parameter determining the dynamic shared memory implementation to use

dynamic_shared_memory_type is a a configuration parameter determining which dynamic shared memory implementation to use.

dynamic_shared_memory_type was added in PostgreSQL 9.4.


Possible values are:

  • posix
  • sysv
  • windows
  • mmap

Not all values are supported on all platforms.

Use of mmap is not recommended, as the operating system may repeatedly write modified pages back to disk, increasing system I/O load.

Default value

The default value for dynamic_shared_memory_type is the first of the above values supported on the local system.

For Linux et al this will be posix; for Windows, windows.

mmap is not the default for any platform.

Change history


GUC configuration item, Memory

See also