bzr commit into mysql-5.1 branch (kristofer.pettersson:2690) Bug#40386

[Kristofer Pettersson]

#At file:///home/thek/Development/cpp/mysqlbzr/mysql-5.1-bug40386/

 2690 Kristofer Pettersson	2008-10-31
      Bug#40386 Not flushing query cache after truncate
      
      This patch solves a regression which caused TRUNCATE TABLE on an InnoDB table
      to to keep an invalid result set in the query cache.
added:
  mysql-test/r/innodb_querycache.result
  mysql-test/t/innodb_querycache.test
modified:
  sql/sql_delete.cc

per-file messages:
  sql/sql_delete.cc
    * Always invalidate query cache since we don't know if any rows were removed.
=== added file 'mysql-test/r/innodb_querycache.result'
--- a/mysql-test/r/innodb_querycache.result	1970-01-01 00:00:00 +0000
+++ b/mysql-test/r/innodb_querycache.result	2008-10-31 14:52:01 +0000
@@ -0,0 +1,33 @@
+SET GLOBAL query_cache_size=1024*512;
+CREATE TABLE t1 (c1 int) ENGINE InnoDB;
+INSERT INTO t1 VALUES (12345);
+FLUSH STATUS;
+SELECT * FROM t1;
+c1
+12345
+SHOW STATUS LIKE 'Qcache_queries_in_cache';
+Variable_name	Value
+Qcache_queries_in_cache	1
+SELECT * FROM t1;
+c1
+12345
+SHOW STATUS LIKE 'Qcache_queries_in_cache';
+Variable_name	Value
+Qcache_queries_in_cache	1
+SHOW STATUS LIKE 'Qcache_hits';
+Variable_name	Value
+Qcache_hits	1
+TRUNCATE TABLE t1;
+SHOW STATUS LIKE 'Qcache_queries_in_cache';
+Variable_name	Value
+Qcache_queries_in_cache	0
+SELECT * FROM t1;
+c1
+SHOW STATUS LIKE 'Qcache_queries_in_cache';
+Variable_name	Value
+Qcache_queries_in_cache	1
+SHOW STATUS LIKE 'Qcache_hits';
+Variable_name	Value
+Qcache_hits	1
+DROP TABLE t1;
+SET GLOBAL query_cache_size=0;

=== added file 'mysql-test/t/innodb_querycache.test'
--- a/mysql-test/t/innodb_querycache.test	1970-01-01 00:00:00 +0000
+++ b/mysql-test/t/innodb_querycache.test	2008-10-31 14:52:01 +0000
@@ -0,0 +1,23 @@
+--source include/have_query_cache.inc
+--source include/have_innodb.inc
+
+#
+# Bug#40386 Not flushing query cache after truncate
+#
+SET GLOBAL query_cache_size=1024*512;
+CREATE TABLE t1 (c1 int) ENGINE InnoDB;
+INSERT INTO t1 VALUES (12345);
+FLUSH STATUS;
+SELECT * FROM t1;
+SHOW STATUS LIKE 'Qcache_queries_in_cache';
+SELECT * FROM t1;
+SHOW STATUS LIKE 'Qcache_queries_in_cache';
+SHOW STATUS LIKE 'Qcache_hits';
+TRUNCATE TABLE t1;
+SHOW STATUS LIKE 'Qcache_queries_in_cache';
+SELECT * FROM t1;
+SHOW STATUS LIKE 'Qcache_queries_in_cache';
+SHOW STATUS LIKE 'Qcache_hits';
+DROP TABLE t1;
+SET GLOBAL query_cache_size=0;
+

=== modified file 'sql/sql_delete.cc'
--- a/sql/sql_delete.cc	2008-07-17 18:26:55 +0000
+++ b/sql/sql_delete.cc	2008-10-31 14:52:01 +0000
@@ -355,13 +355,10 @@ bool mysql_delete(THD *thd, TABLE_LIST *
 
 cleanup:
   /*
-    Invalidate the table in the query cache if something changed. This must
-    be before binlog writing and ha_autocommit_...
+    Invalidate the table in the query cache because we don't know if something
+    changed. This must be before binlog writing and ha_autocommit_...
   */
-  if (deleted)
-  {
-    query_cache_invalidate3(thd, table_list, 1);
-  }
+  query_cache_invalidate3(thd, table_list, 1);
 
   delete select;
   transactional_table= table->file->has_transactions();