Introduce wal_level GUC to explicitly control if information needed for

archival or hot standby should be WAL-logged, instead of deducing that from
other options like archive_mode. This replaces recovery_connections GUC in
the primary, where it now has no effect, but it's still used in the standby
to enable/disable hot standby.

Remove the WAL-logging of "unlogged operations", like creating an index
without WAL-logging and fsyncing it at the end. Instead, we keep a copy of
the wal_mode setting and the settings that affect how much shared memory a
hot standby server needs to track master transactions (max_connections,
max_prepared_xacts, max_locks_per_xact) in pg_control. Whenever the settings
change, at server restart, write a WAL record noting the new settings and
update pg_control. This allows us to notice the change in those settings in
the standby at the right moment, they used to be included in checkpoint
records, but that meant that a changed value was not reflected in the
standby until the first checkpoint after the change.

Bump PG_CONTROL_VERSION and XLOG_PAGE_MAGIC. Whack XLOG_PAGE_MAGIC back to
the sequence it used to follow, before hot standby and subsequent patches
changed it to 0x9003.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c
index e8a4fc2e938..30723327cd2 100644
--- a/src/backend/storage/ipc/standby.c
+++ b/src/backend/storage/ipc/standby.c
@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/ipc/standby.c,v 1.19 2010/04/23 23:21:44 rhaas Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/ipc/standby.c,v 1.20 2010/04/28 16:10:42 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -256,7 +256,7 @@ ResolveRecoveryConflictWithSnapshot(TransactionId latestRemovedXid, RelFileNode
 	 */
 	if (!TransactionIdIsValid(latestRemovedXid))
 	{
-		elog(DEBUG1, "Invalid latestremovexXid reported, using latestcompletedxid instead");
+		elog(DEBUG1, "invalid latestremovexXid reported, using latestcompletedxid instead");
 
 		LWLockAcquire(ProcArrayLock, LW_SHARED);
 		latestRemovedXid = ShmemVariableCache->latestCompletedXid;