Use DELETE instead of UPDATE to speed up vacuum test

melanieplageman · melanieplageman · commit 9744fe24118b · 2024-07-29T15:42:10.000-04:00
e2e9928 introduced a test which generated dead tuples for vacuum with an UPDATE. The test only required enough dead TIDs for two rounds of index vacuuming. This can be accomplished with a DELETE instead of an UPDATE -- which generates about 50% less WAL and makes the test 20% faster in many cases. The test takes several seconds (more on slow buildfarm animals) because we need quite a few tuples to trigger two rounds of index vacuuming; so it is worth a follow-on commit to speed it up. Suggested-by: Masahiko Sawada Discussion: https://postgr.es/m/CAAKRu_bWmMjmqL%2BOZ2duEQ80u7cRvpsExLNZNjzk-pXX5skwMQ%40mail.gmail.com Backpatch-through: 14, the first version containing this test.
diff --git a/src/test/recovery/t/043_vacuum_horizon_floor.pl b/src/test/recovery/t/043_vacuum_horizon_floor.pl
@@ -70,7 +70,7 @@
 	CREATE TABLE ${table1}(col1 int) with (autovacuum_enabled=false);
 	INSERT INTO $table1 SELECT generate_series(1, 200000);
 	CREATE INDEX on ${table1}(col1);
-	UPDATE $table1 SET col1 = 0 WHERE col1 > 1;
+	DELETE FROM $table1 WHERE col1 > 1;
 	INSERT INTO $table1 VALUES(1);
 ]);
 
