Fix for BUG#12228: SP cache code:

* Cleanup SP Cache code, now SP Cache only deletes sp_head objects in 
  sp_cache_flush_obsolete() invalidates all pointers to routines in the cache.
* Use new SP Cache use contract in the code.

There is no test case because it doesn't seem to be possible to cause thread races to end
the same way they end in heavy-load test. This patch removes the crash in heavy test.


mysql-test/r/type_bit.result:
  Drop the tables this test tries to create
mysql-test/r/view.result:
  Drop function this test creates
mysql-test/t/type_bit.test:
  Drop the tables this test tries to create
mysql-test/t/view.test:
  Drop function this test creates
sql/sp.cc:
  Fix for BUG#12228: When a routine is deleted/modified, invalidate all cached SPs in all
  threads. We need to do so because sp_lex_keeper::{prelocking_tables, query_tables_own_last}
  in one SP may depend on another SP sp_lex_keeper::m_lex is using.
sql/sp_cache.cc:
  Fix for BUG#12228:
  * Move class sp_cache to here from sp_cache.h, document the functions.
  * sp_cache_insert, sp_cache_remove, sp_cache_invalidate and sp_cache_lookup must not delete
    sp_head* objects as they may be called during SP execution when sp_head objects are used.
  * Added sp_cache_flush_obsolete() function that may delete sp_head objects.
  * Removed sp_cache_remove as there is no need for it now - when we change one SP we should
    invalidate all other SPs, because sp_lex_keeper::{prelocking_tables, 
    query_tables_own_last} from one SP depend on content of another SP (used in 
    sp_lex_keeper::m_lex).
sql/sp_cache.h:
  Fix for BUG#12228:
  * Move class sp_cache to sp_cache.cc it is not needed in .h file
  * Added comments
sql/sql_parse.cc:
  Fix for BUG#12228: Call new sp_cache_flush_obsolete() function before running the query
sql/sql_prepare.cc:
  Fix for BUG#12228: Call new sp_cache_flush_obsolete() function before preparing/executing a PS

1 files changed, 23 insertions, 78 deletions

diff --git a/sql/sp_cache.h b/sql/sp_cache.h
index 14b2db97f5f..402647db9ea 100644
--- a/sql/sp_cache.h
+++ b/sql/sp_cache.h
@@ -25,94 +25,39 @@
 /*
   Stored procedures/functions cache. This is used as follows:
    * Each thread has its own cache.
-   * Each sp_head object is put into its thread cache before it is used, and 
+   * Each sp_head object is put into its thread cache before it is used, and
      then remains in the cache until deleted.
 */
 
 class sp_head;
 class sp_cache;
 
-/* Initialize the SP caching once at startup */
-void sp_cache_init();
+/*
+  Cache usage scenarios:
+  1. Application-wide init:
+    sp_cache_init();
+
+  2. SP execution in thread:
+  2.1 While holding sp_head* pointers:
+  
+    // look up a routine in the cache (no checks if it is up to date or not)
+    sp_cache_lookup(); 
+    
+    sp_cache_insert();
+    sp_cache_invalidate();
+  
+  2.2 When not holding any sp_head* pointers (at query end):
+    sp_cache_flush_obsolete();
+  
+  3. Before thread exit:
+    sp_cache_clear();
+*/
 
-/* Clear the cache *cp and set *cp to NULL */
+void sp_cache_init();
 void sp_cache_clear(sp_cache **cp);
-
-/* Insert an SP into cache. If 'cp' points to NULL, it's set to a new cache */
 void sp_cache_insert(sp_cache **cp, sp_head *sp);
-
-/* Lookup an SP in cache */
 sp_head *sp_cache_lookup(sp_cache **cp, sp_name *name);
-
-/* 
-  Remove an SP from cache, and also bump the Cversion number so all other 
-  caches are invalidated. 
-  Returns true if something was removed.
-*/
-bool sp_cache_remove(sp_cache **cp, sp_name *name);
-
-/* Invalidate all existing SP caches by bumping Cversion number. */
 void sp_cache_invalidate();
-
-
-/*
- *
- * The cache class. Don't use this directly, use the C API above
- *
- */
-
-class sp_cache
-{
-public:
-
-  ulong version;
-
-  sp_cache();
-
-  ~sp_cache();
-
-  void
-  init();
-
-  void
-  cleanup();
-
-  inline void
-  insert(sp_head *sp)
-  {
-    my_hash_insert(&m_hashtable, (const byte *)sp);
-  }
-
-  inline sp_head *
-  lookup(char *name, uint namelen)
-  {
-    return (sp_head *)hash_search(&m_hashtable, (const byte *)name, namelen);
-  }
-
-  inline bool
-  remove(char *name, uint namelen)
-  {
-    sp_head *sp= lookup(name, namelen);
-
-    if (sp)
-    {
-      hash_delete(&m_hashtable, (byte *)sp);
-      return TRUE;
-    }
-    return FALSE;
-  }
-
-  inline void
-  remove_all()
-  {
-    cleanup();
-    init();
-  }
-
-private:
-
-  HASH m_hashtable;
-
-}; // class sp_cache
+void sp_cache_flush_obsolete(sp_cache **cp);
 
 #endif /* _SP_CACHE_H_ */