GIF89a; EcchiShell v1.0
//proc/self/root/usr/include/pgsql/= XLogFileSize) \ { \ recptr.xlogid += 1; \ recptr.xrecoff \ = recptr.xrecoff + nbytes - XLogFileSize; \ } \ else \ recptr.xrecoff += nbytes; \ } while (0) /* * TimeLineID (TLI) - identifies different database histories to prevent * confusion after restoring a prior state of a database installation. * TLI does not change in a normal stop/restart of the database (including * crash-and-recover cases); but we must assign a new TLI after doing * a recovery to a prior state, a/k/a point-in-time recovery. This makes * the new WAL logfile sequence we generate distinguishable from the * sequence that was generated in the previous incarnation. */ typedef uint32 TimeLineID; /* * Because O_DIRECT bypasses the kernel buffers, and because we never * read those buffers except during crash recovery or if wal_level != minimal, * it is a win to use it in all cases where we sync on each write(). We could * allow O_DIRECT with fsync(), but it is unclear if fsync() could process * writes not buffered in the kernel. Also, O_DIRECT is never enough to force * data to the drives, it merely tries to bypass the kernel cache, so we still * need O_SYNC/O_DSYNC. */ #ifdef O_DIRECT #define PG_O_DIRECT O_DIRECT #else #define PG_O_DIRECT 0 #endif /* * This chunk of hackery attempts to determine which file sync methods * are available on the current platform, and to choose an appropriate * default method. We assume that fsync() is always available, and that * configure determined whether fdatasync() is. */ #if defined(O_SYNC) #define OPEN_SYNC_FLAG O_SYNC #elif defined(O_FSYNC) #define OPEN_SYNC_FLAG O_FSYNC #endif #if defined(O_DSYNC) #if defined(OPEN_SYNC_FLAG) /* O_DSYNC is distinct? */ #if O_DSYNC != OPEN_SYNC_FLAG #define OPEN_DATASYNC_FLAG O_DSYNC #endif #else /* !defined(OPEN_SYNC_FLAG) */ /* Win32 only has O_DSYNC */ #define OPEN_DATASYNC_FLAG O_DSYNC #endif #endif #if defined(PLATFORM_DEFAULT_SYNC_METHOD) #define DEFAULT_SYNC_METHOD PLATFORM_DEFAULT_SYNC_METHOD #elif defined(OPEN_DATASYNC_FLAG) #define DEFAULT_SYNC_METHOD SYNC_METHOD_OPEN_DSYNC #elif defined(HAVE_FDATASYNC) #define DEFAULT_SYNC_METHOD SYNC_METHOD_FDATASYNC #else #define DEFAULT_SYNC_METHOD SYNC_METHOD_FSYNC #endif /* * Limitation of buffer-alignment for direct IO depends on OS and filesystem, * but XLOG_BLCKSZ is assumed to be enough for it. */ #ifdef O_DIRECT #define ALIGNOF_XLOG_BUFFER XLOG_BLCKSZ #else #define ALIGNOF_XLOG_BUFFER ALIGNOF_BUFFER #endif #endif /* XLOG_DEFS_H */