Merge of query cache from 4.1 to 5.0

mysql-test/r/ndb_cache.result:
  Added 'order by' to select's
mysql-test/r/ndb_cache2.result:
  Added 'order by' to select's
mysql-test/t/ndb_cache.test:
  Added 'order by' to select's
mysql-test/t/ndb_cache2.test:
  Added 'order by' to select's
sql/ha_innodb.h:
  Changed function name
sql/ha_ndbcluster.cc:
  Merge from query cache from 4.1 to 5.0
  Added better comments
  ndb_get_table_statistics had changed, so there where some adaptions to make
sql/ha_ndbcluster.h:
  Changed name of function
sql/handler.h:
  Changed name of function
sql/sql_cache.cc:
  Changed name of function

mysql-test/r/ndb_cache.result

@@ -36,22 +36,22 @@ Variable_name	Value
 Qcache_hits	1
 insert into t1 value (2, 7, 8, 'Second row');
 insert into t1 value (4, 5, 6, 'Fourth row');
-select * from t1;
+select * from t1 order by pk;
 pk	a	b	c
+1	3	3	First row
 2	7	8	Second row
 4	5	6	Fourth row
-1	3	3	First row
 show status like "Qcache_inserts";
 Variable_name	Value
 Qcache_inserts	3
 show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	1
-select * from t1;
+select * from t1 order by pk;
 pk	a	b	c
+1	3	3	First row
 2	7	8	Second row
 4	5	6	Fourth row
-1	3	3	First row
 show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	2
@@ -81,10 +81,10 @@ show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	3
 use test;
-select * from t1;
+select * from t1 order by pk;
 pk	a	b	c
-2	7	8	Second row
 1	3	3	First row
+2	7	8	Second row
 select * from t1 where b=3;
 pk	a	b	c
 1	3	3	First row
@@ -96,11 +96,11 @@ use test;
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	0
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	4	3	First row
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	4	3	First row
@@ -110,11 +110,11 @@ Qcache_inserts	7
 show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	5
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	4	3	First row
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	4	3	First row
@@ -138,7 +138,7 @@ Qcache_inserts	7
 show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	7
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	4	3	First row
@@ -161,7 +161,7 @@ Qcache_inserts	8
 show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	7
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	5	3	First row
@@ -171,7 +171,7 @@ Qcache_inserts	9
 show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	7
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	5	3	First row

mysql-test/r/ndb_cache2.result

@@ -37,10 +37,10 @@ Variable_name	Value
 Qcache_hits	1
 insert into t1 value (2, 7, 8, 'Second row');
 insert into t1 value (4, 5, 6, 'Fourth row');
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
-2	7	8	Second row
 4	5	6	Fourth row
+2	7	8	Second row
 1	3	3	First row
 show status like "Qcache_inserts";
 Variable_name	Value
@@ -48,10 +48,10 @@ Qcache_inserts	3
 show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	1
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
-2	7	8	Second row
 4	5	6	Fourth row
+2	7	8	Second row
 1	3	3	First row
 show status like "Qcache_hits";
 Variable_name	Value
@@ -82,7 +82,7 @@ show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	3
 use test;
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	3	3	First row
@@ -97,11 +97,11 @@ use test;
 show status like "Qcache_queries_in_cache";
 Variable_name	Value
 Qcache_queries_in_cache	0
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	4	3	First row
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	4	3	First row
@@ -111,11 +111,11 @@ Qcache_inserts	7
 show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	5
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	4	3	First row
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	4	3	First row
@@ -139,7 +139,7 @@ Qcache_inserts	7
 show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	7
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	4	3	First row
@@ -162,7 +162,7 @@ Qcache_inserts	8
 show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	7
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	5	3	First row
@@ -172,7 +172,7 @@ Qcache_inserts	9
 show status like "Qcache_hits";
 Variable_name	Value
 Qcache_hits	7
-select * from t1;
+select * from t1 order by pk desc;
 pk	a	b	c
 2	7	8	Second row
 1	5	3	First row

mysql-test/t/ndb_cache.test

@@ -35,10 +35,10 @@ show status like "Qcache_hits";
 # Insert a new record and make sure the correct data is returned
 insert into t1 value (2, 7, 8, 'Second row');
 insert into t1 value (4, 5, 6, 'Fourth row');
-select * from t1;
+select * from t1 order by pk;
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
-select * from t1;
+select * from t1 order by pk;
 show status like "Qcache_hits";
 
 # Perform a "new" query and make sure the query cache is not hit
@@ -60,7 +60,7 @@ show status like "Qcache_hits";
 connect (con1,localhost,root,,);
 connection con1;
 use test;
-select * from t1;
+select * from t1 order by pk;
 select * from t1 where b=3;
 show status like "Qcache_hits";
 
@@ -70,13 +70,13 @@ connect (con2,localhost,root,,);
 connection con2;
 use test;
 show status like "Qcache_queries_in_cache";
-select * from t1;
-select * from t1;
+select * from t1 order by pk desc;
+select * from t1 order by pk desc;
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
 connection con1;
-select * from t1;
-select * from t1;
+select * from t1 order by pk desc;
+select * from t1 order by pk desc;
 show status like "Qcache_queries_in_cache";
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
@@ -92,7 +92,7 @@ show status like "Qcache_queries_in_cache";
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
 connection con2;
-select * from t1;
+select * from t1 order by pk desc;
 show status like "Qcache_queries_in_cache";
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
@@ -103,11 +103,11 @@ show status like "Qcache_queries_in_cache";
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
 connection con2;
-select * from t1;
+select * from t1 order by pk desc;
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
 connection con1;
-select * from t1;
+select * from t1 order by pk desc;
 show status like "Qcache_queries_in_cache";
 show status like "Qcache_inserts";
 show status like "Qcache_hits";

mysql-test/t/ndb_cache2.test

@@ -41,10 +41,10 @@ show status like "Qcache_hits";
 # Insert a new record and make sure the correct data is returned
 insert into t1 value (2, 7, 8, 'Second row');
 insert into t1 value (4, 5, 6, 'Fourth row');
-select * from t1;
+select * from t1 order by pk desc;
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
-select * from t1;
+select * from t1 order by pk desc;
 show status like "Qcache_hits";
 
 # Perform a "new" query and make sure the query cache is not hit
@@ -66,7 +66,7 @@ show status like "Qcache_hits";
 connect (con1,localhost,root,,);
 connection con1;
 use test;
-select * from t1;
+select * from t1 order by pk desc;
 select * from t1 where b=3;
 show status like "Qcache_hits";
 
@@ -76,13 +76,13 @@ connect (con2,localhost,root,,);
 connection con2;
 use test;
 show status like "Qcache_queries_in_cache";
-select * from t1;
-select * from t1;
+select * from t1 order by pk desc;
+select * from t1 order by pk desc;
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
 connection con1;
-select * from t1;
-select * from t1;
+select * from t1 order by pk desc;
+select * from t1 order by pk desc;
 show status like "Qcache_queries_in_cache";
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
@@ -95,7 +95,7 @@ show status like "Qcache_queries_in_cache";
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
 connection con2;
-select * from t1;
+select * from t1 order by pk desc;
 show status like "Qcache_queries_in_cache";
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
@@ -107,11 +107,11 @@ show status like "Qcache_queries_in_cache";
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
 connection con2;
-select * from t1;
+select * from t1 order by pk desc;
 show status like "Qcache_inserts";
 show status like "Qcache_hits";
 connection con1;
-select * from t1;
+select * from t1 order by pk desc;
 show status like "Qcache_queries_in_cache";
 show status like "Qcache_inserts";
 show status like "Qcache_hits";

sql/ha_innodb.h

@@ -180,7 +180,7 @@ class ha_innobase: public handler
         /*
           ask handler about permission to cache table during query registration
         */
-        my_bool cached_table_registration(THD *thd, char *table_key,
+        my_bool register_query_cache_table(THD *thd, char *table_key,
 					   uint key_length,
 					   qc_engine_callback *call_back,
 					   ulonglong *engine_data)

sql/ha_ndbcluster.cc

@@ -4026,7 +4026,6 @@ ha_ndbcluster::ha_ndbcluster(TABLE *table_arg):
   m_force_send(TRUE),
   m_autoincrement_prefetch(32),
   m_transaction_on(TRUE),
-  m_use_local_query_cache(FALSE),
   m_multi_cursor(NULL)
 { 
   int i;
@@ -4820,31 +4819,48 @@ uint ndb_get_commitcount(THD* thd, char* dbname, char* tabname,
     DBUG_RETURN(1);
   ndb->setDatabaseName(dbname);
   
-  if (ndb_get_table_statistics(ndb, tabname, 0, commit_count))
+  struct Ndb_statistics stat;
+  if (ndb_get_table_statistics(ndb, tabname, &stat))
     DBUG_RETURN(1);
+  *commit_count= stat.commit_count;
   DBUG_RETURN(0);
 }
 
 
-static
-my_bool
-ndbcluster_cache_retrieval_allowed(
-/*======================================*/
-				/* out: TRUE if permitted, FALSE if not;
-				note that the value FALSE means invalidation
-				of query cache if *engine_data is changed */
-	THD*	thd,		/* in: thd of the user who is trying to
-				store a result to the query cache or
-				retrieve it */
-	char*	full_name,	/* in: concatenation of database name,
+/*
+  Check if a cached query can be used.
+  This is done by comparing the supplied engine_data to commit_count of 
+  the table.
+  The commit_count is either retrieved from the share for the table, where 
+  it has been cached by the util thread. If the util thread is not started, 
+  NDB has to be contacetd to retrieve the commit_count, this will introduce
+  a small delay while waiting for NDB to answer.
+  
+  
+  SYNOPSIS
+  ndbcluster_cache_retrieval_allowed
+    thd            thread handle
+    full_name      concatenation of database name,
                    the null character '\0', and the table
-				name */
-	uint	full_name_len,	/* in: length of the full name, i.e.
-				len(dbname) + len(tablename) + 1 */
-        ulonglong *engine_data) /* in: value set in call to 
-				ha_ndbcluster::cached_table_registration
-				   out: if return FALSE this is used to invalidate 
-				all cached queries with this table*/
+                   name 
+    full_name_len  length of the full name, 
+                   i.e. len(dbname) + len(tablename) + 1
+
+    engine_data    parameter retrieved when query was first inserted into 
+                   the cache. If the value of engine_data is changed, 
+                   all queries for this table should be invalidated.
+
+  RETURN VALUE
+    TRUE  Yes, use the query from cache
+    FALSE No, don't use the cached query, and if engine_data
+          has changed, all queries for this table should be invalidated
+
+*/
+
+static my_bool 
+ndbcluster_cache_retrieval_allowed(THD*	thd, 
+				   char* full_name, uint full_name_len, 
+				   ulonglong *engine_data)
 {
   DBUG_ENTER("ndbcluster_cache_retrieval_allowed");
 
@@ -4861,7 +4877,7 @@ ndbcluster_cache_retrieval_allowed(
 
   if (ndb_get_commitcount(thd, dbname, tabname, &commit_count))
   {
-    *engine_data= *engine_data+1; // invalidate
+    *engine_data+= 1; // invalidate
     DBUG_RETURN(FALSE);
   }
   DBUG_PRINT("info", ("*engine_data=%llu, commit_count=%llu", 
@@ -4877,27 +4893,36 @@ ndbcluster_cache_retrieval_allowed(
   DBUG_RETURN(TRUE);
 }
 
-my_bool
-ha_ndbcluster::cached_table_registration(
-/*======================================*/
-				/* out: TRUE if permitted, FALSE if not;
-				note that the value FALSE means invalidation
-				of query cache if *engine_data is changed */
-	THD*	thd,		/* in: thd of the user who is trying to
-				store a result to the query cache or
-				retrieve it */
-	char*	full_name,	/* in: concatenation of database name,
+
+/**
+   Register a table for use in the query cache. Fetch the commit_count
+   for the table and return it in engine_data, this will later be used 
+   to check if the table has changed, before the cached query is reused.
+
+   SYNOPSIS
+   ha_ndbcluster::can_query_cache_table
+    thd            thread handle
+    full_name      concatenation of database name,
                    the null character '\0', and the table
-				name */
-	uint	full_name_len,	/* in: length of the full name, i.e.
-				len(dbname) + len(tablename) + 1 */
-	qc_engine_callback 
-	*engine_callback,       /* out: function to be called before using
-				   cache on this table */
-        ulonglong *engine_data) /* out: if return FALSE this is used to 
-				   invalidate all cached queries with this table*/
+                   name 
+    full_name_len  length of the full name, 
+                   i.e. len(dbname) + len(tablename) + 1
+    qc_engine_callback  function to be called before using cache on this table 
+    engine_data    out, commit_count for this table
+
+  RETURN VALUE
+    TRUE  Yes, it's ok to cahce this query
+    FALSE No, don't cach the query
+
+*/
+
+my_bool
+ha_ndbcluster::register_query_cache_table(THD* thd, 
+					  char* full_name, uint full_name_len,
+					  qc_engine_callback *engine_callback,
+					  ulonglong *engine_data) 
 {
-  DBUG_ENTER("ha_ndbcluster::cached_table_registration");
+  DBUG_ENTER("ha_ndbcluster::register_query_cache_table");
 
   bool is_autocommit= !(thd->options & (OPTION_NOT_AUTOCOMMIT | OPTION_BEGIN));
   DBUG_PRINT("enter",("dbname=%s, tabname=%s, is_autocommit=%d",
@@ -5139,10 +5164,6 @@ ndb_get_table_statistics(Ndb* ndb, const char * table,
     pOp->close(TRUE);
 
     ndb->closeTransaction(pTrans);
-    if(row_count)
-      *row_count= sum_rows;
-    if(commit_count)
-      *commit_count= sum_commits;
 
     ndbstat->row_count= sum_rows;
     ndbstat->commit_count= sum_commits;
@@ -5662,13 +5683,12 @@ extern "C" pthread_handler_decl(ndb_util_thread_func,arg __attribute__((unused))
       
       // Contact NDB to get commit count for table
       g_ndb->setDatabaseName(db);
-      Uint64 rows, commit_count;
-      if(ndb_get_table_statistics(g_ndb, tabname, 
-				  &rows, &commit_count) == 0){
+      struct Ndb_statistics stat;;
+      if(ndb_get_table_statistics(g_ndb, tabname, &stat) == 0){
 	DBUG_PRINT("ndb_util_thread", 
 		   ("Table: %s, rows: %llu, commit_count: %llu", 
-		    share->table_name, rows, commit_count));
-	share->commit_count= commit_count;
+		    share->table_name, stat.row_count, stat.commit_count));
+	share->commit_count= stat.commit_count;
       }
       else
       {

sql/ha_ndbcluster.h

@@ -157,11 +157,11 @@ class ha_ndbcluster: public handler
   static Thd_ndb* seize_thd_ndb();
   static void release_thd_ndb(Thd_ndb* thd_ndb);
   uint8 table_cache_type();
-  my_bool cached_table_registration(THD *thd, char *table_key,
+  my_bool register_query_cache_table(THD *thd, char *table_key,
 				     uint key_length,
 				     qc_engine_callback *engine_callback,
 				     ulonglong *engine_data);
- private:
+private:
   int alter_table_name(const char *to);
   int drop_table();
   int create_index(const char *name, KEY *key_info, bool unique);

sql/handler.h

@@ -592,10 +592,11 @@ public:
 
   /* Type of table for caching query */
   virtual uint8 table_cache_type() { return HA_CACHE_TBL_NONTRANSACT; }
-  /* ask handler about permission to cache table during query registration */
-  virtual my_bool cached_table_registration(THD *thd, char *table_key,
+  /* ask handler about permission to cache table when query is to be cached */
+  virtual my_bool register_query_cache_table(THD *thd, char *table_key,
 					     uint key_length,
-                                            qc_engine_callback *engine_callback,
+					     qc_engine_callback 
+					     *engine_callback,
 					     ulonglong *engine_data)
   {
     *engine_callback= 0;

sql/sql_cache.cc

@@ -2770,7 +2770,8 @@ my_bool Query_cache::ask_handler_allowance(THD *thd,
   for (; tables_used; tables_used= tables_used->next_global)
   {
     TABLE *table= tables_used->table;
-    if (!handler->cached_table_registration(thd, table->s->table_cache_key,
+    handler *handler= table->file;
+    if (!handler->register_query_cache_table(thd, table->s->table_cache_key,
 					     table->s->key_length,
 					     &tables_used->callback_func,
 					     &tables_used->engine_data))