From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 1 Apr 2009 18:54:27 +0000 (+0000)
Subject: Improve pg_dump's query for retrieving BLOB comments to be more efficient
X-Git-Url: http://waps.l3s.uni-hannover.de/gitweb/?a=commitdiff_plain;h=e4216c5e872174175e94d9117d9a7a06e81c65ff;p=users%2Fsimon%2Fpostgres.git

Improve pg_dump's query for retrieving BLOB comments to be more efficient
when there are many blobs and not so many comments.  Tamas Vincze
---

diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index e4ea6eefa0..29335264c0 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -1995,7 +1995,13 @@ dumpBlobComments(Archive *AH, void *arg)
 	selectSourceSchema("pg_catalog");
 
 	/* Cursor to get all BLOB comments */
-	if (AH->remoteVersion >= 70200)
+	if (AH->remoteVersion >= 70300)
+		blobQry = "DECLARE blobcmt CURSOR FOR SELECT loid, "
+				  "obj_description(loid, 'pg_largeobject') "
+				  "FROM (SELECT DISTINCT loid FROM "
+				  "pg_description d JOIN pg_largeobject l ON (objoid = loid) "
+				  "WHERE classoid = 'pg_largeobject'::regclass) ss";
+	else if (AH->remoteVersion >= 70200)
 		blobQry = "DECLARE blobcmt CURSOR FOR SELECT loid, "
 				  "obj_description(loid, 'pg_largeobject') "
 				  "FROM (SELECT DISTINCT loid FROM pg_largeobject) ss";