diff -ur mysql-5.1.34.orig/mysql-test/r/query_cache.result mysql-5.1.34/mysql-test/r/query_cache.result
--- mysql-5.1.34.orig/mysql-test/r/query_cache.result	2009-03-31 16:27:19.000000000 +0100
+++ mysql-5.1.34/mysql-test/r/query_cache.result	2009-05-28 19:18:17.000000000 +0100
@@ -38,10 +38,16 @@
 show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	1
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	0
 drop table t1;
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	0
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	1
 create table t1 (a int not null);
 insert into t1 values (1),(2),(3);
 create table t2 (a int not null);
@@ -69,10 +75,16 @@
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	1
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	1
 insert into t2  values (7);
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	0
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	2
 select * from t1;
 a
 1
@@ -89,10 +101,16 @@
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	1
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	2
 insert into t3 values (8);
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	0
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	3
 select * from t3;
 a
 1
@@ -106,10 +124,16 @@
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	1
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	3
 update t2 set a=9 where a=7;
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	0
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	4
 select * from t1;
 a
 1
@@ -119,10 +143,16 @@
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	1
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	4
 update t3 set a=10 where a=1;
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	0
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	5
 select * from t3;
 a
 10
@@ -136,10 +166,16 @@
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	1
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	5
 delete from t2 where a=9;
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	0
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	6
 select * from t1;
 a
 10
@@ -149,10 +185,16 @@
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	1
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	6
 delete from t3 where a=10;
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	0
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	7
 drop table t1, t2, t3;
 set query_cache_type=demand;
 create table t1 (a int not null);
@@ -197,11 +239,17 @@
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	1
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	7
 set query_cache_type=on;
 reset query cache;
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	0
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	7
 select sql_no_cache * from t1;
 a
 1
@@ -475,6 +523,9 @@
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	1
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	15
 insert delayed into t1 values (4);
 select a from t1;
 a
@@ -485,6 +536,9 @@
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	1
+show status like "Qcache_queries_invalidated";
+Variable_name	Value
+Qcache_queries_invalidated	16
 drop table t1;
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
diff -ur mysql-5.1.34.orig/mysql-test/t/query_cache.test mysql-5.1.34/mysql-test/t/query_cache.test
--- mysql-5.1.34.orig/mysql-test/t/query_cache.test	2009-03-31 16:26:32.000000000 +0100
+++ mysql-5.1.34/mysql-test/t/query_cache.test	2009-05-28 19:16:45.000000000 +0100
@@ -37,10 +37,12 @@
 show status like "Qcache_queries_in_cache";
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
+show status like "Qcache_queries_invalidated";
 
 drop table t1;
 
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 
 #
 # MERGE TABLES with INSERT/UPDATE and DELETE
@@ -55,32 +57,44 @@
 select * from t3;
 show status like "Qcache_hits";
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 insert into t2  values (7);
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 select * from t1;
 select * from t1;
 show status like "Qcache_hits";
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 insert into t3 values (8);
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 # update
 select * from t3;
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 update t2 set a=9 where a=7;
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 select * from t1;
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 update t3 set a=10 where a=1;
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 #delete
 select * from t3;
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 delete from t2 where a=9;
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 select * from t1;
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 delete from t3 where a=10;
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 drop table t1, t2, t3;
 #
 # SELECT SQL_CACHE ...
@@ -100,12 +114,14 @@
 select * from t1 where a IN (select a from t1 union select sql_cache a from t1);
 show status like "Qcache_hits";
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 set query_cache_type=on;
 #
 # RESET QUERY CACHE
 #
 reset query cache;
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 #
 # SELECT SQL_NO_CACHE
 #
@@ -299,10 +315,12 @@
 select * from t1;
 select * from t1;
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 insert delayed into t1 values (4);
 --sleep 5     # Wait for insert delayed to be executed.
 select a from t1;
 show status like "Qcache_queries_in_cache";
+show status like "Qcache_queries_invalidated";
 drop table t1;
 show status like "Qcache_queries_in_cache";
 
@@ -1302,7 +1320,7 @@
 CREATE TABLE t1 (a LONGBLOB);
 INSERT INTO t1 SET a = 'aaaa';
 INSERT INTO t1 SET a = 'aaaa';
-SELECT 1 FROM t1 GROUP BY
+	SELECT 1 FROM t1 GROUP BY
   (SELECT LAST_INSERT_ID() FROM t1 ORDER BY MIN(a) ASC LIMIT 1);
 DROP TABLE t1;
 
diff -ur mysql-5.1.34.orig/sql/mysqld.cc mysql-5.1.34/sql/mysqld.cc
--- mysql-5.1.34.orig/sql/mysqld.cc	2009-03-31 15:39:47.000000000 +0100
+++ mysql-5.1.34/sql/mysqld.cc	2009-05-28 13:48:55.000000000 +0100
@@ -7382,6 +7382,7 @@
   {"Qcache_inserts",           (char*) &query_cache.inserts,    SHOW_LONG},
   {"Qcache_lowmem_prunes",     (char*) &query_cache.lowmem_prunes, SHOW_LONG},
   {"Qcache_not_cached",        (char*) &query_cache.refused,    SHOW_LONG},
+  {"Qcache_queries_invalidated",(char*) &query_cache.invalidated, SHOW_LONG},
   {"Qcache_queries_in_cache",  (char*) &query_cache.queries_in_cache, SHOW_LONG_NOFLUSH},
   {"Qcache_total_blocks",      (char*) &query_cache.total_blocks, SHOW_LONG_NOFLUSH},
 #endif /*HAVE_QUERY_CACHE*/
diff -ur mysql-5.1.34.orig/sql/sql_cache.cc mysql-5.1.34/sql/sql_cache.cc
--- mysql-5.1.34.orig/sql/sql_cache.cc	2009-03-31 15:39:51.000000000 +0100
+++ mysql-5.1.34/sql/sql_cache.cc	2009-05-28 13:48:26.000000000 +0100
@@ -2664,6 +2664,7 @@
     Query_cache_block *query_block= list_root->next->block();
     BLOCK_LOCK_WR(query_block);
     free_query(query_block);
+    query_cache.invalidated++;
     DBUG_EXECUTE_IF("debug_cache_locks", sleep(10););
   }
 }
diff -ur mysql-5.1.34.orig/sql/sql_cache.h mysql-5.1.34/sql/sql_cache.h
--- mysql-5.1.34.orig/sql/sql_cache.h	2009-03-31 15:39:51.000000000 +0100
+++ mysql-5.1.34/sql/sql_cache.h	2009-05-28 13:23:13.000000000 +0100
@@ -268,7 +268,7 @@
   ulong query_cache_size, query_cache_limit;
   /* statistics */
   ulong free_memory, queries_in_cache, hits, inserts, refused,
-    free_memory_blocks, total_blocks, lowmem_prunes;
+    free_memory_blocks, total_blocks, lowmem_prunes, invalidated;
 
 
 private: