Update copyright for 2016

[postgresql] / src / include / access / xlogdefs.h

diff --git a/src/include/access/xlogdefs.h b/src/include/access/xlogdefs.h
index 6926bd792ac9e009d4bd8336d94c740c8c968288..c2c6632e633d076284ea9d75b778d37ce3f70e6c 100644 (file)
--- a/src/include/access/xlogdefs.h
+++ b/src/include/access/xlogdefs.h
@@ -4,53 +4,34 @@
  * Postgres transaction log manager record pointer and
  * timeline number definitions
  *
- * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/xlogdefs.h,v 1.16 2007/01/05 22:19:51 momjian Exp $
+ * src/include/access/xlogdefs.h
  */
 #ifndef XLOG_DEFS_H
 #define XLOG_DEFS_H
 
+#include <fcntl.h>                             /* need open() flags */
+
 /*
  * Pointer to a location in the XLOG.  These pointers are 64 bits wide,
  * because we don't want them ever to overflow.
- *
- * NOTE: xrecoff == 0 is used to indicate an invalid pointer.  This is OK
- * because we use page headers in the XLOG, so no XLOG record can start
- * right at the beginning of a file.
- *
- * NOTE: the "log file number" is somewhat misnamed, since the actual files
- * making up the XLOG are much smaller than 4Gb.  Each actual file is an
- * XLogSegSize-byte "segment" of a logical log file having the indicated
- * xlogid.     The log file number and segment number together identify a
- * physical XLOG file. Segment number and offset within the physical file
- * are computed from xrecoff div and mod XLogSegSize.
  */
-typedef struct XLogRecPtr
-{
-       uint32          xlogid;                 /* log file #, 0 based */
-       uint32          xrecoff;                /* byte offset of location in log file */
-} XLogRecPtr;
-
+typedef uint64 XLogRecPtr;
 
 /*
- * Macros for comparing XLogRecPtrs
- *
- * Beware of passing expressions with side-effects to these macros,
- * since the arguments may be evaluated multiple times.
+ * Zero is used indicate an invalid pointer. Bootstrap skips the first possible
+ * WAL segment, initializing the first WAL page at XLOG_SEG_SIZE, so no XLOG
+ * record can begin at zero.
  */
-#define XLByteLT(a, b)         \
-                       ((a).xlogid < (b).xlogid || \
-                        ((a).xlogid == (b).xlogid && (a).xrecoff < (b).xrecoff))
-
-#define XLByteLE(a, b)         \
-                       ((a).xlogid < (b).xlogid || \
-                        ((a).xlogid == (b).xlogid && (a).xrecoff <= (b).xrecoff))
-
-#define XLByteEQ(a, b)         \
-                       ((a).xlogid == (b).xlogid && (a).xrecoff == (b).xrecoff)
+#define InvalidXLogRecPtr      0
+#define XLogRecPtrIsInvalid(r) ((r) == InvalidXLogRecPtr)
 
+/*
+ * XLogSegNo - physical log file sequence number.
+ */
+typedef uint64 XLogSegNo;
 
 /*
  * TimeLineID (TLI) - identifies different database histories to prevent
@@ -63,4 +44,59 @@ typedef struct XLogRecPtr
  */
 typedef uint32 TimeLineID;
 
+/*
+ * Replication origin id - this is located in this file to avoid having to
+ * include origin.h in a bunch of xlog related places.
+ */
+typedef uint16 RepOriginId;
+
+/*
+ *     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
+
 #endif   /* XLOG_DEFS_H */