From: Date: August 22 2007 11:17am
Subject: bk commit into 5.0 tree (gshchepa:1.2498) BUG#30201
List-Archive: http://lists.mysql.com/commits/32858
X-Bug: 30201
Message-Id: <20070822091742.48D3C3D43AF@localhost.localdomain>

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5.0 repository of uchum. When uchum does a push these changes will
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ChangeSet@stripped, 2007-08-22 14:17:35+05:00, gshchepa@stripped +1 -0
  Fixed bug #30201.
  Killing a SELECT query with KILL QUERY or KILL CONNECTION
  causes a server crash if the query cache is enabled.
  
  Normal evaluation of a query may be interrupted by the
  KILL QUERY/CONNECTION statement, in this case the mysql_execute_command
  function returns TRUE, and the thd->killed flag has true value.
  In this case the result of the query may
  be cached incompletely (omitting call to query_cache_insert inside
  the net_real_write function), and next call to query_cache_end_of_result
  may lead to server crash.
  Thus, the query_cache_end_of_result function has been modified to abort
  query cache in the case of killed thread.
  

  sql/sql_cache.cc@stripped, 2007-08-22 14:14:09+05:00, gshchepa@stripped +21 -16
    Fixed bug #30201.
    The  query_cache_end_of_result function has been modified to abort query
    cache in the case of query execution failure. Also this function has been
    modified to remove incomplete query block.

diff -Nrup a/sql/sql_cache.cc b/sql/sql_cache.cc
--- a/sql/sql_cache.cc	2007-05-10 17:54:53 +05:00
+++ b/sql/sql_cache.cc	2007-08-22 14:14:09 +05:00
@@ -706,6 +706,12 @@ void query_cache_end_of_result(THD *thd)
   Query_cache_block *query_block;
   DBUG_ENTER("query_cache_end_of_result");
 
+  if (thd->killed)
+  {
+    query_cache_abort(&thd->net);
+    DBUG_VOID_RETURN;
+  }
+
   /* See the comment on double-check locking usage above. */
   if (thd->net.query_cache_query == 0)
     DBUG_VOID_RETURN;
@@ -727,27 +733,26 @@ void query_cache_end_of_result(THD *thd)
     DUMP(&query_cache);
     BLOCK_LOCK_WR(query_block);
     Query_cache_query *header= query_block->query();
-    Query_cache_block *last_result_block= header->result()->prev;
-    ulong allign_size= ALIGN_SIZE(last_result_block->used);
-    ulong len= max(query_cache.min_allocation_unit, allign_size);
-    if (last_result_block->length >= query_cache.min_allocation_unit + len)
-      query_cache.split_block(last_result_block,len);
+    Query_cache_block *last_result_block;
+    ulong allign_size;
+    ulong len;
 
-#ifndef DBUG_OFF
     if (header->result() == 0)
     {
-      DBUG_PRINT("error", ("end of data whith no result. query '%s'",
-                           header->query()));
-      query_cache.wreck(__LINE__, "");
-
-      /*
-        We do not need call of BLOCK_UNLOCK_WR(query_block); here because
-        query_cache.wreck() switched query cache off but left content
-        untouched for investigation (it is debugging method).
-      */
+      DBUG_PRINT("error", ("End of data with no result blocks; "
+                           "Query '%s' removed from cache.", header->query()));
+
+      BLOCK_UNLOCK_WR(query_block);
+      query_cache.free_query(query_block);
       goto end;
     }
-#endif
+
+    last_result_block= header->result()->prev;
+    allign_size= ALIGN_SIZE(last_result_block->used);
+    len= max(query_cache.min_allocation_unit, allign_size);
+    if (last_result_block->length >= query_cache.min_allocation_unit + len)
+      query_cache.split_block(last_result_block,len);
+
     header->found_rows(current_thd->limit_found_rows);
     header->result()->type= Query_cache_block::RESULT;
     header->writer(0);