WL#2985 "Partition pruning": addition2: perform partition pruning for

single-table UPDATE/DELETE.


mysql-test/r/partition_pruning.result:
  WL#2985 "Partition pruning": addition2: perform partition pruning for UPDATE/DELETE:
  testcases added
mysql-test/t/partition_pruning.test:
  WL#2985 "Partition pruning": addition2: perform partition pruning for UPDATE/DELETE:
  testcases added
sql/sql_delete.cc:
  WL#2985 "Partition pruning": addition2: perform partition pruning for UPDATE/DELETE:
  Added partition pruning call in mysql_delete()
sql/sql_update.cc:
  WL#2985 "Partition pruning": addition2: perform partition pruning for UPDATE/DELETE:
  Added partition pruning call in mysql_update()

mysql-test/r/partition_pruning.result

@@ -304,3 +304,42 @@ id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 explain partitions select * from t1 where b >  1 and b < 3 and (a =1 or a =2);
 id	select_type	table	partitions	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	p1_sp2,p2_sp2	ALL	NULL	NULL	NULL	NULL	3	Using where
+drop table t1;
+create table t1 (a int) partition by list(a) (
+partition p0 values in (1,2),
+partition p1 values in (3,4)
+);
+insert into t1 values (1),(1),(2),(2),(3),(4),(3),(4);
+flush status;
+update t1 set a=100 where a=5;
+show status like 'Handler_read_rnd_next';
+Variable_name	Value
+Handler_read_rnd_next	0
+flush status;
+update t1 set a=100 where a+1=5+1;
+show status like 'Handler_read_rnd_next';
+Variable_name	Value
+Handler_read_rnd_next	10
+flush status;
+delete from t1 where a=5;
+show status like 'Handler_read_rnd_next';
+Variable_name	Value
+Handler_read_rnd_next	0
+flush status;
+delete from t1 where a+1=5+1;
+show status like 'Handler_read_rnd_next';
+Variable_name	Value
+Handler_read_rnd_next	10
+create table t2 like t1;
+insert into t2 select * from t2;
+flush status;
+update t1,t2 set t1.a=1000, t2.a=1000 where t1.a=5 and t2.a=5;
+show status like 'Handler_read_rnd_next';
+Variable_name	Value
+Handler_read_rnd_next	3
+flush status;
+delete t1,t2 from t1, t2 where t1.a=5 and t2.a=5;
+show status like 'Handler_read_rnd_next';
+Variable_name	Value
+Handler_read_rnd_next	3
+drop table t1,t2;

mysql-test/t/partition_pruning.test

@@ -269,6 +269,52 @@ insert into t1 values (1,1),(2,2),(3,3);
 
 explain partitions select * from t1 where b >  1 and b < 3;
 explain partitions select * from t1 where b >  1 and b < 3 and (a =1 or a =2);
+drop table t1;
+
+# Test partition pruning for single-table UPDATE/DELETE.
+# TODO: Currently we test only "all partitions pruned away" case. Add more
+# tests when the patch that makes use of partition pruning results at
+# execution phase is pushed.
+
+create table t1 (a int) partition by list(a) (
+  partition p0 values in (1,2),
+  partition p1 values in (3,4)
+);
+insert into t1 values (1),(1),(2),(2),(3),(4),(3),(4);
+
+# This won't do any table access
+flush status;
+update t1 set a=100 where a=5;
+show status like 'Handler_read_rnd_next';
+
+# ... as compared to this, which will scan both partitions
+flush status;
+update t1 set a=100 where a+1=5+1;
+show status like 'Handler_read_rnd_next';
+
+# Same as above for DELETE:
+flush status;
+delete from t1 where a=5;
+show status like 'Handler_read_rnd_next';
+
+flush status;
+delete from t1 where a+1=5+1;
+show status like 'Handler_read_rnd_next';
+
+# Same as above multi-table UPDATE/DELETE
+create table t2 like t1;
+insert into t2 select * from t2;
+
+flush status;
+update t1,t2 set t1.a=1000, t2.a=1000 where t1.a=5 and t2.a=5;
+show status like 'Handler_read_rnd_next';
+# ^ This shows 3 accesses, these are caused by const table reads. 
+# They should vanish when partition pruning results are used.
+
+flush status;
+delete t1,t2 from t1, t2 where t1.a=5 and t2.a=5;
+show status like 'Handler_read_rnd_next';
+drop table t1,t2;
 
 # No tests for NULLs in RANGE(monotonic_expr()) - they depend on BUG#15447
 # being fixed.

sql/sql_delete.cc

@@ -100,6 +100,21 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
     /* Handler didn't support fast delete; Delete rows one by one */
   }
 
+#ifdef WITH_PARTITION_STORAGE_ENGINE
+  if (prune_partitions(thd, table, conds))
+  {
+    free_underlaid_joins(thd, select_lex);
+    thd->row_count_func= 0;
+    send_ok(thd);				// No matching records
+    DBUG_RETURN(0);
+  }
+  /* 
+    Update the table->records number (note: we probably could remove the
+    previous file->info() call)
+  */
+  table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
+#endif
+
   table->used_keys.clear_all();
   table->quick_keys.clear_all();		// Can't use 'only index'
   select=make_select(table, 0, 0, conds, 0, &error);
@@ -111,13 +126,11 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
     free_underlaid_joins(thd, select_lex);
     thd->row_count_func= 0;
     send_ok(thd,0L);
-
     /*
       We don't need to call reset_auto_increment in this case, because
       mysql_truncate always gives a NULL conds argument, hence we never
       get here.
     */
-
     DBUG_RETURN(0);				// Nothing to delete
   }
 

sql/sql_update.cc

@@ -244,6 +244,21 @@ int mysql_update(THD *thd,
   }
   // Don't count on usage of 'only index' when calculating which key to use
   table->used_keys.clear_all();
+
+#ifdef WITH_PARTITION_STORAGE_ENGINE
+  if (prune_partitions(thd, table, conds))
+  {
+    free_underlaid_joins(thd, select_lex);
+    send_ok(thd);				// No matching records
+    DBUG_RETURN(0);
+  }
+  /* 
+    Update the table->records number (note: we probably could remove the
+    previous file->info() call)
+  */
+  table->file->info(HA_STATUS_VARIABLE | HA_STATUS_NO_LOCK);
+#endif
+
   select= make_select(table, 0, 0, conds, 0, &error);
   if (error || !limit ||
       (select && select->check_quick(thd, safe_update, limit)))