3882 Ole John Aske 2012-05-02
WL#5940 changes according to 'round #2' comments from Evgeny P.
This is intended to be the last set of changes related to these comments.
The handler extension ::test_push_flag() has now been removed.
The two remaining HA_PUSH_<foo>-flags related to this extension
has been made obsolete by:
- HA_PUSH_BLOCK_CONST_TABLE is replaced with the 'test_flag'
HA_BLOCK_CONST_TABLE. Furthermore it was identified that
usage of this flag was obsolete at one of the places it was used.
(As 'system' table optimization is not possible for handlers
with non-EXACT statistics)
- HA_PUSH_MULTIPLE_DEPENDENCY has been entirely removed as this
covered a corner case with questionable advantage of being pushed.
Previous changes to join_no_more_records() has been reverted.
modified:
sql/ha_ndbcluster.cc
sql/ha_ndbcluster.h
sql/handler.h
sql/sql_executor.cc
sql/sql_optimizer.cc
sql/sql_select.cc
3881 Ole John Aske 2012-04-27
Added fix to pushed join JSON explain to WL#5940 branch
modified:
sql/opt_explain_json.cc
=== modified file 'sql/ha_ndbcluster.cc'
--- a/sql/ha_ndbcluster.cc 2012-04-25 11:41:51 +0000
+++ b/sql/ha_ndbcluster.cc 2012-05-02 12:33:07 +0000
@@ -12344,6 +12344,21 @@ ulonglong ha_ndbcluster::table_flags(voi
*/
if (thd->variables.binlog_format == BINLOG_FORMAT_STMT)
f= (f | HA_BINLOG_STMT_CAPABLE) & ~HA_HAS_OWN_BINLOGGING;
+
+ /**
+ * To maximize join pushability we want const-table optimization
+ * blocked if table is possibly pushable, that is:
+ * - Variable 'ndb_join_pushdown= on'
+ * - Lock mode is LM_CommittedRead
+ * - There are no BLOBs in this table
+ */
+ if (THDVAR(thd, join_pushdown) &&
+ get_ndb_lock_mode(m_lock.type) == NdbOperation::LM_CommittedRead &&
+ !(table_share && table_share->blob_fields > 0))
+ {
+ f= f | HA_BLOCK_CONST_TABLE;
+ }
+
return f;
}
@@ -14503,57 +14518,6 @@ ha_ndbcluster::parent_of_pushed_join() c
return NULL;
}
-bool
-ha_ndbcluster::test_push_flag(enum ha_push_flag flag) const
-{
- DBUG_ENTER("test_push_flag");
- switch (flag) {
- case HA_PUSH_BLOCK_CONST_TABLE:
- {
- /**
- * We don't support join push down if...
- * - not LM_CommittedRead
- * - uses blobs
- */
- THD *thd= current_thd;
- if (unlikely(!THDVAR(thd, join_pushdown)))
- DBUG_RETURN(false);
-
- if (table->read_set != NULL && uses_blob_value(table->read_set))
- {
- DBUG_RETURN(false);
- }
-
- NdbOperation::LockMode lm= get_ndb_lock_mode(m_lock.type);
-
- if (lm != NdbOperation::LM_CommittedRead)
- {
- DBUG_RETURN(false);
- }
-
- DBUG_RETURN(true);
- }
- case HA_PUSH_MULTIPLE_DEPENDENCY:
- /**
- * If any child operation within this pushed join refer
- * column values (paramValues), the pushed join has dependencies
- * in addition to the root operation itself.
- */
- if (m_pushed_join_operation==PUSHED_ROOT &&
- m_pushed_join_member->get_field_referrences_count() > 0) // Childs has field refs
- {
- DBUG_RETURN(true);
- }
- DBUG_RETURN(false);
-
- default:
- DBUG_ASSERT(0);
- DBUG_RETURN(false);
- }
- DBUG_RETURN(false);
-}
-
-
/**
@param[in] comment table comment defined by user
=== modified file 'sql/ha_ndbcluster.h'
--- a/sql/ha_ndbcluster.h 2012-03-30 06:52:25 +0000
+++ b/sql/ha_ndbcluster.h 2012-05-02 12:33:07 +0000
@@ -415,8 +415,6 @@ static void set_tabname(const char *path
bool maybe_pushable_join(const char*& reason) const;
int assign_pushed_join(const ndb_pushed_join* pushed_join);
- bool test_push_flag(enum ha_push_flag flag) const;
-
uint number_of_pushed_joins() const;
const TABLE* root_of_pushed_join() const;
const TABLE* parent_of_pushed_join() const;
=== modified file 'sql/handler.h'
--- a/sql/handler.h 2012-03-30 06:52:25 +0000
+++ b/sql/handler.h 2012-05-02 12:33:07 +0000
@@ -189,6 +189,12 @@ enum enum_alter_inplace_result {
*/
#define HA_READ_BEFORE_WRITE_REMOVAL (LL(1) << 38)
+/*
+ The handler don't want accesses to this table to
+ be const-table optimized
+*/
+#define HA_BLOCK_CONST_TABLE (LL(1) << 39)
+
/* bits in index_flags(index_number) for what you can do with index */
#define HA_READ_NEXT 1 /* TODO really use this flag */
#define HA_READ_PREV 2 /* supports ::index_prev */
@@ -410,21 +416,6 @@ namespace AQP {
class Join_plan;
};
-/* Flag used for for test_push_flag() */
-enum ha_push_flag {
-
- /* Handler want to block const table optimization */
- HA_PUSH_BLOCK_CONST_TABLE
-
- /* Handler reports a pushed join as having multiple dependencies
- if its results does not only depend on the root operation:
- ie. results from some child operations does not only depend
- on results from the root operation and/or other child operations
- within this pushed join
- */
- ,HA_PUSH_MULTIPLE_DEPENDENCY
-};
-
/**
struct xid_t is binary compatible with the XID structure as
in the X/Open CAE Specification, Distributed Transaction Processing:
@@ -2464,11 +2455,6 @@ public:
virtual const TABLE* parent_of_pushed_join() const
{ return NULL; }
- virtual bool test_push_flag(enum ha_push_flag flag) const
- {
- return FALSE;
- }
-
virtual int index_read_pushed(uchar * buf, const uchar * key,
key_part_map keypart_map)
{ return HA_ERR_WRONG_COMMAND; }
=== modified file 'sql/sql_executor.cc'
--- a/sql/sql_executor.cc 2012-03-30 06:52:25 +0000
+++ b/sql/sql_executor.cc 2012-05-02 12:33:07 +0000
@@ -3115,19 +3115,8 @@ join_read_last_key(JOIN_TAB *tab)
/* ARGSUSED */
static int
-join_no_more_records(READ_RECORD *info)
+join_no_more_records(READ_RECORD *info __attribute__((unused)))
{
- /**
- * When a pushed join completes, and its results did not only depend on
- * the key of this root operations: ('tab->ref.key_buff')
- * Results from this pushed join can not be reused
- * for later queries having the same root key.
- * (ref: join_read_key(), join_read_const() & join_read_system()
- */
- if (info->table->file->test_push_flag(HA_PUSH_MULTIPLE_DEPENDENCY))
- {
- info->table->status= STATUS_GARBAGE;
- }
return -1;
}
=== modified file 'sql/sql_optimizer.cc'
--- a/sql/sql_optimizer.cc 2012-04-25 11:52:33 +0000
+++ b/sql/sql_optimizer.cc 2012-05-02 12:33:07 +0000
@@ -3050,14 +3050,6 @@ make_join_statistics(JOIN *join, TABLE_L
*/
extract_method= extract_no_table;
}
- else if (table->file->test_push_flag(HA_PUSH_BLOCK_CONST_TABLE))
- {
- /*
- Handler implements pushed joins, and prefer const tables to
- be pushed together with rest of the pushed query.
- */
- extract_method= extract_no_table;
- }
else if (*s->on_expr_ref)
{
/* s is the only inner table of an outer join, extract empty tables */
@@ -3241,7 +3233,7 @@ const_table_extraction_done:
!tl->in_outer_join_nest() && // 2
!(tl->embedding && tl->embedding->sj_on_expr) && // 3
!(*s->on_expr_ref && (*s->on_expr_ref)->is_expensive()) &&// 4
- !table->file->test_push_flag(HA_PUSH_BLOCK_CONST_TABLE)) // 5
+ !(table->file->ha_table_flags() & HA_BLOCK_CONST_TABLE)) // 5
{
if (table->key_info[key].flags & HA_NOSAME)
{
=== modified file 'sql/sql_select.cc'
--- a/sql/sql_select.cc 2012-04-18 10:46:39 +0000
+++ b/sql/sql_select.cc 2012-05-02 12:33:07 +0000
@@ -1510,7 +1510,7 @@ bool create_ref_for_key(JOIN *join, JOIN
j->ref.null_ref_key= null_ref_key;
}
else if (keyuse_uses_no_tables &&
- !table->file->test_push_flag(HA_PUSH_BLOCK_CONST_TABLE))
+ !(table->file->ha_table_flags() & HA_BLOCK_CONST_TABLE))
{
/*
This happen if we are using a constant expression in the ON part
No bundle (reason: useless for push emails).
| Thread |
|---|
| • bzr push into mysql-trunk branch (ole.john.aske:3881 to 3882) WL#5940 | Ole John Aske | 2 May |
