Clean up and document the API for XLogOpenRelation and XLogReadBuffer.

This commit doesn't make much functional change, but it does eliminate some
duplicated code --- for instance, PageIsNew tests are now done inside
XLogReadBuffer rather than by each caller.
The GIST xlog code still needs a lot of love, but I'll worry about that
separately.

3 files changed, 21 insertions, 16 deletions

diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c
index a9b19ab89a..209362782a 100644
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@@ -15,7 +15,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.178 2006/03/24 04:32:13 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.179 2006/03/29 21:17:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -671,7 +671,7 @@ dropdb(const char *dbname, bool missing_ok)
 	 * is important to ensure that no remaining backend tries to write out a
 	 * dirty buffer to the dead database later...
 	 */
-	DropBuffers(db_id);
+	DropDatabaseBuffers(db_id);
 
 	/*
 	 * Also, clean out any entries in the shared free space map.
@@ -1377,11 +1377,16 @@ dbase_redo(XLogRecPtr lsn, XLogRecord *record)
 
 		dst_path = GetDatabasePath(xlrec->db_id, xlrec->tablespace_id);
 
-		/*
-		 * Drop pages for this database that are in the shared buffer cache
-		 */
-		DropBuffers(xlrec->db_id);
+		/* Drop pages for this database that are in the shared buffer cache */
+		DropDatabaseBuffers(xlrec->db_id);
+
+		/* Also, clean out any entries in the shared free space map */
+		FreeSpaceMapForgetDatabase(xlrec->db_id);
+
+		/* Clean out the xlog relcache too */
+		XLogDropDatabase(xlrec->db_id);
 
+		/* And remove the physical files */
 		if (!rmtree(dst_path, true))
 			ereport(WARNING,
 					(errmsg("could not remove database directory \"%s\"",
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c
index 144cf73c8a..0e448271e1 100644
--- a/src/backend/commands/sequence.c
+++ b/src/backend/commands/sequence.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.130 2006/03/24 04:32:13 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/sequence.c,v 1.131 2006/03/29 21:17:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1140,14 +1140,8 @@ seq_redo(XLogRecPtr lsn, XLogRecord *record)
 		elog(PANIC, "seq_redo: unknown op code %u", info);
 
 	reln = XLogOpenRelation(xlrec->node);
-	if (!RelationIsValid(reln))
-		return;
-
-	buffer = XLogReadBuffer(true, reln, 0);
-	if (!BufferIsValid(buffer))
-		elog(PANIC, "seq_redo: can't read block 0 of rel %u/%u/%u",
-			 xlrec->node.spcNode, xlrec->node.dbNode, xlrec->node.relNode);
-
+	buffer = XLogReadBuffer(reln, 0, true);
+	Assert(BufferIsValid(buffer));
 	page = (Page) BufferGetPage(buffer);
 
 	/* Always reinit the page and reinstall the magic number */
diff --git a/src/backend/commands/tablespace.c b/src/backend/commands/tablespace.c
index 84b8f02736..bafea91dfc 100644
--- a/src/backend/commands/tablespace.c
+++ b/src/backend/commands/tablespace.c
@@ -37,7 +37,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.33 2006/03/29 15:15:43 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.34 2006/03/29 21:17:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -468,6 +468,12 @@ DropTableSpace(DropTableSpaceStmt *stmt)
 	}
 
 	/*
+	 * Note: because we checked that the tablespace was empty, there should
+	 * be no need to worry about flushing shared buffers or free space map
+	 * entries for relations in the tablespace.
+	 */
+
+	/*
 	 * Allow TablespaceCreateDbspace again.
 	 */
 	LWLockRelease(TablespaceCreateLock);