Implement archive_timeout feature to force xlog file switches to occur no more

than N seconds apart.  This allows a simple, if not very high performance,
means of guaranteeing that a PITR archive is no more than N seconds behind
real time.  Also make pg_current_xlog_location return the WAL Write pointer,
add pg_current_xlog_insert_location to return the Insert pointer, and fix
pg_xlogfile_name_offset to return its results as a two-element record instead
of a smashed-together string, as per recent discussion.

Simon Riggs

4 files changed, 19 insertions, 7 deletions

diff --git a/src/include/access/xlog.h b/src/include/access/xlog.h
index e076979a44b..22b0f0bb7be 100644
--- a/src/include/access/xlog.h
+++ b/src/include/access/xlog.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.72 2006/07/13 16:49:19 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/access/xlog.h,v 1.73 2006/08/17 23:04:08 tgl Exp $
  */
 #ifndef XLOG_H
 #define XLOG_H
@@ -139,6 +139,7 @@ extern XLogRecPtr ProcLastRecEnd;
 extern int	CheckPointSegments;
 extern int	XLOGbuffers;
 extern char *XLogArchiveCommand;
+extern int	XLogArchiveTimeout;
 extern char *XLOG_sync_method;
 extern const char XLOG_sync_method_default[];
 
diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.h
index 03bf0e86231..773e85fbcdb 100644
--- a/src/include/access/xlog_internal.h
+++ b/src/include/access/xlog_internal.h
@@ -11,11 +11,13 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/access/xlog_internal.h,v 1.15 2006/08/07 16:57:57 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/xlog_internal.h,v 1.16 2006/08/17 23:04:08 tgl Exp $
  */
 #ifndef XLOG_INTERNAL_H
 #define XLOG_INTERNAL_H
 
+#include <time.h>
+
 #include "access/xlog.h"
 #include "fmgr.h"
 #include "storage/block.h"
@@ -237,6 +239,12 @@ typedef struct RmgrData
 
 extern const RmgrData RmgrTable[];
 
+/* 
+ * Exported to support xlog switching from bgwriter
+ */
+extern time_t GetLastSegSwitchTime(void);
+extern XLogRecPtr RequestXLogSwitch(void);
+
 /*
  * These aren't in xlog.h because I'd rather not include fmgr.h there.
  */
@@ -244,6 +252,7 @@ extern Datum pg_start_backup(PG_FUNCTION_ARGS);
 extern Datum pg_stop_backup(PG_FUNCTION_ARGS);
 extern Datum pg_switch_xlog(PG_FUNCTION_ARGS);
 extern Datum pg_current_xlog_location(PG_FUNCTION_ARGS);
+extern Datum pg_current_xlog_insert_location(PG_FUNCTION_ARGS);
 extern Datum pg_xlogfile_name_offset(PG_FUNCTION_ARGS);
 extern Datum pg_xlogfile_name(PG_FUNCTION_ARGS);
 
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index d2141f1b385..6728188e501 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.349 2006/08/12 02:52:06 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.350 2006/08/17 23:04:08 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200608101
+#define CATALOG_VERSION_NO	200608171
 
 #endif
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index 5c0824ef041..93a1e0c1ed0 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.420 2006/08/06 03:53:44 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.421 2006/08/17 23:04:10 tgl Exp $
  *
  * NOTES
  *	  The script catalog/genbki.sh reads this file and generates .bki
@@ -3104,8 +3104,10 @@ DESCR("Finish taking an online backup");
 DATA(insert OID = 2848 ( pg_switch_xlog			PGNSP PGUID 12 f f t f v 0 25 "" _null_ _null_ _null_ pg_switch_xlog - _null_ ));
 DESCR("Switch to new xlog file");
 DATA(insert OID = 2849 ( pg_current_xlog_location	PGNSP PGUID 12 f f t f v 0 25 "" _null_ _null_ _null_ pg_current_xlog_location - _null_ ));
-DESCR("current xlog location");
-DATA(insert OID = 2850 ( pg_xlogfile_name_offset	PGNSP PGUID 12 f f t f i 1 25 "25" _null_ _null_ _null_ pg_xlogfile_name_offset - _null_ ));
+DESCR("current xlog write location");
+DATA(insert OID = 2852 ( pg_current_xlog_insert_location	PGNSP PGUID 12 f f t f v 0 25 "" _null_ _null_ _null_ pg_current_xlog_insert_location - _null_ ));
+DESCR("current xlog insert location");
+DATA(insert OID = 2850 ( pg_xlogfile_name_offset	PGNSP PGUID 12 f f t f i 1 2249 "25" "{25,25,23}" "{i,o,o}" "{wal_location,file_name,file_offset}" pg_xlogfile_name_offset - _null_ ));
 DESCR("xlog filename and byte offset, given an xlog location");
 DATA(insert OID = 2851 ( pg_xlogfile_name			PGNSP PGUID 12 f f t f i 1 25 "25" _null_ _null_ _null_ pg_xlogfile_name - _null_ ));
 DESCR("xlog filename, given an xlog location");