postgresql/src/include/port/linux.h

23 lines
1.0 KiB
C

/* src/include/port/linux.h */
/*
* As of July 2007, all known versions of the Linux kernel will sometimes
* return EIDRM for a shmctl() operation when EINVAL is correct (it happens
* when the low-order 15 bits of the supplied shm ID match the slot number
* assigned to a newer shmem segment). We deal with this by assuming that
* EIDRM means EINVAL in PGSharedMemoryIsInUse(). This is reasonably safe
* since in fact Linux has no excuse for ever returning EIDRM; it doesn't
* track removed segments in a way that would allow distinguishing them from
* private ones. But someday that code might get upgraded, and we'd have
* to have a kernel version test here.
*/
#define HAVE_LINUX_EIDRM_BUG
/*
* Set the default wal_sync_method to fdatasync. With recent Linux versions,
* xlogdefs.h's normal rules will prefer open_datasync, which (a) doesn't
* perform better and (b) causes outright failures on ext4 data=journal
* filesystems, because those don't support O_DIRECT.
*/
#define PLATFORM_DEFAULT_WAL_SYNC_METHOD WAL_SYNC_METHOD_FDATASYNC