From: Date: July 24 2006 5:33pm
Subject: bk commit into 4.1 tree (gkodinov:1.2537) BUG#21019
List-Archive: http://lists.mysql.com/commits/9504
X-Bug: 21019
Message-Id: <20060724153321.3177921EFC1@macbook.gmz>

Below is the list of changes that have just been committed into a local
4.1 repository of kgeorge. When kgeorge does a push these changes will
be propagated to the main repository and, within 24 hours after the
push, to the public repository.
For information on how to access the public repository
see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet@stripped, 2006-07-24 18:33:08+03:00, gkodinov@stripped +3 -0
  Bug #21019: First result of SELECT COUNT(*) different than consecutive runs
   When optimizing conditions like 'a = <some_val> OR a IS NULL' so that they're
   united into a single condition on the key and checked together it must check
   which value is the NULL value in a correct way : not only using ->is_null but
   also check if the expression doesn't depend on tables.

  mysql-test/r/select.result@stripped, 2006-07-24 18:32:59+03:00, gkodinov@stripped +26 -0
    Bug #21019: First result of SELECT COUNT(*) different than consecutive runs
     - test case

  mysql-test/t/select.test@stripped, 2006-07-24 18:33:00+03:00, gkodinov@stripped +15 -0
    Bug #21019: First result of SELECT COUNT(*) different than consecutive runs
     - test case

  sql/sql_select.cc@stripped, 2006-07-24 18:33:01+03:00, gkodinov@stripped +1 -1
    Bug #21019: First result of SELECT COUNT(*) different than consecutive runs
     - check whether a value is null in the correct way.

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	gkodinov
# Host:	macbook.gmz
# Root:	/Users/kgeorge/mysql/work/B21019-4.1-opt

--- 1.460/sql/sql_select.cc	2006-07-24 18:33:21 +03:00
+++ 1.461/sql/sql_select.cc	2006-07-24 18:33:21 +03:00
@@ -2144,7 +2144,7 @@ merge_key_fields(KEY_FIELD *start,KEY_FI
 	  old->level= and_level;
 	  old->optimize= KEY_OPTIMIZE_REF_OR_NULL;
 	  /* Remember the NOT NULL value */
-	  if (old->val->is_null())
+	  if (!old->val->used_tables() && old->val->is_null())
 	    old->val= new_fields->val;
           /* The referred expression can be NULL: */ 
           old->null_rejecting= 0;

--- 1.75/mysql-test/r/select.result	2006-07-24 18:33:21 +03:00
+++ 1.76/mysql-test/r/select.result	2006-07-24 18:33:21 +03:00
@@ -2744,3 +2744,29 @@ SELECT i='1e+01',i=1e+01, i in (1e+01), 
 i='1e+01'	i=1e+01	i in (1e+01)	i in ('1e+01')
 0	1	1	1
 DROP TABLE t1;
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 VALUES (1,1), (2,1), (4,10);
+CREATE TABLE t2 (a int PRIMARY KEY, b int, KEY b (b));
+INSERT INTO t2 VALUES (1,NULL), (2,10);
+ALTER TABLE t1 ENABLE KEYS;
+EXPLAIN SELECT STRAIGHT_JOIN SQL_NO_CACHE COUNT(*) FROM t2, t1 WHERE t1.b = t2.b OR t2.b IS NULL;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	b	b	5	NULL	2	Using index
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+SELECT STRAIGHT_JOIN SQL_NO_CACHE * FROM t2, t1 WHERE t1.b = t2.b OR t2.b IS NULL;
+a	b	a	b
+1	NULL	1	1
+1	NULL	2	1
+1	NULL	4	10
+2	10	4	10
+EXPLAIN SELECT STRAIGHT_JOIN SQL_NO_CACHE COUNT(*) FROM t2, t1 WHERE t1.b = t2.b OR t2.b IS NULL;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	b	b	5	NULL	2	Using index
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
+SELECT STRAIGHT_JOIN SQL_NO_CACHE * FROM t2, t1 WHERE t1.b = t2.b OR t2.b IS NULL;
+a	b	a	b
+1	NULL	1	1
+1	NULL	2	1
+1	NULL	4	10
+2	10	4	10
+DROP TABLE IF EXISTS t1,t2;

--- 1.58/mysql-test/t/select.test	2006-07-24 18:33:21 +03:00
+++ 1.59/mysql-test/t/select.test	2006-07-24 18:33:21 +03:00
@@ -2297,4 +2297,19 @@ INSERT INTO t1 VALUES (10);
 SELECT i='1e+01',i=1e+01, i in (1e+01), i in ('1e+01') FROM t1;
 DROP TABLE t1;
 
+#
+# Bug #21019: First result of SELECT COUNT(*) different than consecutive runs
+#
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 VALUES (1,1), (2,1), (4,10);
+
+CREATE TABLE t2 (a int PRIMARY KEY, b int, KEY b (b));
+INSERT INTO t2 VALUES (1,NULL), (2,10);
+ALTER TABLE t1 ENABLE KEYS;
+
+EXPLAIN SELECT STRAIGHT_JOIN SQL_NO_CACHE COUNT(*) FROM t2, t1 WHERE t1.b = t2.b OR t2.b IS NULL;
+SELECT STRAIGHT_JOIN SQL_NO_CACHE * FROM t2, t1 WHERE t1.b = t2.b OR t2.b IS NULL;
+EXPLAIN SELECT STRAIGHT_JOIN SQL_NO_CACHE COUNT(*) FROM t2, t1 WHERE t1.b = t2.b OR t2.b IS NULL;
+SELECT STRAIGHT_JOIN SQL_NO_CACHE * FROM t2, t1 WHERE t1.b = t2.b OR t2.b IS NULL;
+DROP TABLE IF EXISTS t1,t2;
 # End of 4.1 tests