Type: | enum |
Default: | posix |
Context: | postmaster |
Restart: | true |
Values: | [posix, sysv, mmap] |
Since: | 9.4 |
Specifies the dynamic shared memory implementation that the server should use. Possible values are posix
(for POSIX shared memory allocated using shm_open
), sysv
(for System V shared memory allocated via shmget
), windows
(for Windows shared memory), and mmap
(to simulate shared memory using memory-mapped files stored in the data directory). Not all values are supported on all platforms; the first supported option is the default for that platform. The use of the mmap
option, which is not the default on any platform, is generally discouraged because the operating system may write modified pages back to disk repeatedly, increasing system I/O load; however, it may be useful for debugging, when the pg_dynshmem
directory is stored on a RAM disk, or when other shared memory facilities are not available.
On StackOverflow
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