fixed server crash on moving query block with pointers to same table in it (BUG#988)

removed server options


BitKeeper/deleted/.del-query_cache-master.opt~c4daeaa5e40881:
  Delete: mysql-test/t/query_cache-master.opt
mysql-test/r/query_cache.result:
  test for BUG#988
mysql-test/t/query_cache.test:
  test for BUG#988
  removed server options
sql/sql_cache.cc:
  fixed moving query block with pointers to same table in it

mysql-test/r/query_cache.result

+set GLOBAL query_cache_size=1355776;
 flush query cache;
 flush query cache;
 reset query cache;
 flush status;
-drop table if exists t1,t2,t3;
+drop table if exists t1,t2,t3,t4,t11,t21;
 drop database if exists mysqltest;
 create table t1 (a int not null);
 insert into t1 values (1),(2),(3);
@@ -640,3 +641,43 @@ Variable_name	Value
 Qcache_queries_in_cache	2
 SET OPTION SQL_SELECT_LIMIT=DEFAULT;
 drop table t1;
+flush query cache;
+reset query cache;
+flush status;
+set GLOBAL query_cache_size=1048576;
+create table t1 (a int not null);
+insert into t1 values (1),(2),(3);
+create table t2 (a text not null);
+create table t3 (a text not null);
+insert into t3 values("1111111111111111111111111111111111111111111111111111");
+insert into t2 select * from t3;
+insert into t3 select * from t2;
+insert into t2 select * from t3;
+insert into t3 select * from t2;
+insert into t2 select * from t3;
+insert into t3 select * from t2;
+insert into t2 select * from t3;
+insert into t3 select * from t2;
+insert into t2 select * from t3;
+insert into t3 select * from t2;
+drop table t2;
+create table t2 (a int not null);
+insert into t2 values (1),(2),(3);
+create table t4 (a int not null);
+insert into t4 values (1),(2),(3);
+select * from t4;
+select * from t2;
+select * from t1 as tt, t1 as ttt  where tt.a=1 and ttt.a=2;
+select * from t2;
+select * from t4;
+select * from t1 as tt, t1 as ttt  where tt.a=1 and ttt.a=2;
+select * from t2;
+select * from t4;
+select * from t1 as tt, t1 as ttt  where tt.a=1 and ttt.a=2;
+delete from t2 where a=1;
+flush query cache;
+select * from t3;
+delete from t4 where a=1;
+flush query cache;
+drop table t1,t2,t3,t4;
+set GLOBAL query_cache_size=0;

mysql-test/t/query_cache-master.opt

---set-variable=query_cache_size=1355776

mysql-test/t/query_cache.test

@@ -3,6 +3,7 @@
 #
 # Tests with query cache
 #
+set GLOBAL query_cache_size=1355776;
 
 # Reset query cache variables.
 
@@ -10,7 +11,7 @@ flush query cache; # This crashed in some versions
 flush query cache; # This crashed in some versions
 reset query cache;
 flush status;
-drop table if exists t1,t2,t3;
+drop table if exists t1,t2,t3,t4,t11,t21;
 drop database if exists mysqltest;
 
 #
@@ -450,3 +451,55 @@ select * from t1;
 show status like "Qcache_queries_in_cache";
 SET OPTION SQL_SELECT_LIMIT=DEFAULT;
 drop table t1;
+
+
+#
+# query cache crash on using same table twice in one query test
+#
+flush query cache;
+reset query cache;
+flush status;
+set GLOBAL query_cache_size=1048576;
+
+
+create table t1 (a int not null);
+insert into t1 values (1),(2),(3);
+create table t2 (a text not null);
+create table t3 (a text not null);
+insert into t3 values("1111111111111111111111111111111111111111111111111111");
+insert into t2 select * from t3;
+insert into t3 select * from t2;
+insert into t2 select * from t3;
+insert into t3 select * from t2;
+insert into t2 select * from t3;
+insert into t3 select * from t2;
+insert into t2 select * from t3;
+insert into t3 select * from t2;
+insert into t2 select * from t3;
+insert into t3 select * from t2;
+drop table t2;
+create table t2 (a int not null);
+insert into t2 values (1),(2),(3);
+create table t4 (a int not null);
+insert into t4 values (1),(2),(3);
+
+disable_result_log;
+select * from t4;
+select * from t2;
+select * from t1 as tt, t1 as ttt  where tt.a=1 and ttt.a=2;
+select * from t2;
+select * from t4;
+select * from t1 as tt, t1 as ttt  where tt.a=1 and ttt.a=2;
+select * from t2;
+select * from t4;
+select * from t1 as tt, t1 as ttt  where tt.a=1 and ttt.a=2;
+
+delete from t2 where a=1;
+flush query cache;
+select * from t3;
+enable_result_log;
+delete from t4 where a=1;
+flush query cache;
+
+drop table t1,t2,t3,t4;
+set GLOBAL query_cache_size=0;

sql/sql_cache.cc

@@ -2666,11 +2666,33 @@ my_bool Query_cache::move_by_type(byte **border,
     relink(block, new_block, next, prev, pnext, pprev);
     if (queries_blocks == block)
       queries_blocks = new_block;
+    Query_cache_block_table *beg_of_table_table= block->table(0),
+      *end_of_table_table= block->table(n_tables);
+    byte *beg_of_new_table_table= (byte*) new_block->table(0);
+      
     for (TABLE_COUNTER_TYPE j=0; j < n_tables; j++)
     {
       Query_cache_block_table *block_table = new_block->table(j);
-      block_table->next->prev = block_table;
-      block_table->prev->next = block_table;
+
+      // use aligment from begining of table if 'next' is in same block
+      if ((beg_of_table_table <= block_table->next) &&
+	  (block_table->next < end_of_table_table))
+	((Query_cache_block_table *)(beg_of_new_table_table + 
+				     (((byte*)block_table->next) -
+				      ((byte*)beg_of_table_table))))->prev=
+	 block_table;
+      else
+	block_table->next->prev= block_table;
+
+      // use aligment from begining of table if 'prev' is in same block
+      if ((beg_of_table_table <= block_table->prev) &&
+	  (block_table->prev < end_of_table_table))
+	((Query_cache_block_table *)(beg_of_new_table_table + 
+				     (((byte*)block_table->prev) -
+				      ((byte*)beg_of_table_table))))->next=
+	  block_table;
+      else
+	block_table->prev->next = block_table;
     }
     DBUG_PRINT("qcache", ("after circle tt"));
     *border += len;