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Code Activity

Original idea from Zardosht Kasheff to add HA_CLUSTERED_INDEX

Browse Source 
- Added a lot of code comments
- Updated get_best_ror_intersec() to prefer index scan on not clustered keys before clustered keys.
- Use HA_CLUSTERED_INDEX to define if one should use HA_MRR_INDEX_ONLY
- For test of using index or filesort to resolve ORDER BY, use HA_CLUSTERED_INDEX flag instead of primary_key_is_clustered()
- Use HA_TABLE_SCAN_ON_INDEX instead of primary_key_is_clustered() to decide if ALTER TABLE ... ORDER BY will have any effect.

sql/ha_partition.h:
  Added comment with warning for code unsafe to use with multiple storage engines at the same time
sql/handler.h:
  Added HA_CLUSTERED_INDEX.
  Documented primary_key_is_clustered()
sql/opt_range.cc:
  Added code comments
  Updated get_best_ror_intersec() to ignore clustered keys.
  Optimized away cpk_scan_used and one instance of current_thd (Simpler code)
  Use HA_CLUSTERED_INDEX to define if one should use HA_MRR_INDEX_ONLY
sql/sql_select.cc:
  Changed comment to #ifdef
  For test of using index or filesort to resolve ORDER BY, use HA_CLUSTERED_INDEX flag instead of primary_key_is_clustered()
  (Change is smaller than what it looks beause of indentation change)
sql/sql_table.cc:
  Use HA_TABLE_SCAN_ON_INDEX instead of primary_key_is_clustered() to decide if ALTER TABLE ... ORDER BY will have any effect.
storage/innobase/handler/ha_innodb.h:
  Added support for HA_CLUSTERED_INDEX
storage/innodb_plugin/handler/ha_innodb.cc:
  Added support for HA_CLUSTERED_INDEX
storage/xtradb/handler/ha_innodb.cc:
  Added support for HA_CLUSTERED_INDEX
This commit is contained in:
Michael Widenius
2011-05-18 19:26:30 +03:00
parent 5c70f813f3
commit 3631146442
8 changed files with 123 additions and 63 deletions
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77
sql/sql_select.cc
View File

@ -8550,17 +8550,19 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
else if (!table->covering_keys.is_clear_all() &&
!(tab->select && tab->select->quick))
{ // Only read index tree
#ifdef BAD_OPTIMIZATION
/*
It has turned out that the below change, while speeding things
up for disk-bound loads, slows them down for cases when the data
is in disk cache (see BUG#35850):
// See bug #26447: "Using the clustered index for a table scan
// is always faster than using a secondary index".
It has turned out that the below change, while speeding things
up for disk-bound loads, slows them down for cases when the data
is in disk cache (see BUG#35850):
See bug #26447: "Using the clustered index for a table scan
is always faster than using a secondary index".
*/
if (table->s->primary_key != MAX_KEY &&
table->file->primary_key_is_clustered())
tab->index= table->s->primary_key;
else
*/
#endif
tab->index=find_shortest_key(table, & table->covering_keys);
tab->read_first_record= join_read_first;
/* Read with index_first / index_next */
@ -16525,9 +16527,9 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
*/
DBUG_ASSERT (ref_key != (int) nr);
bool is_covering= table->covering_keys.is_set(nr) ||
(nr == table->s->primary_key &&
table->file->primary_key_is_clustered());
bool is_covering= (table->covering_keys.is_set(nr) ||
(table->file->index_flags(nr, 0, 1) &
HA_CLUSTERED_INDEX));
/*
Don't use an index scan with ORDER BY without limit.
@ -16680,42 +16682,37 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
/*
filesort() and join cache are usually faster than reading in
index order and not using join cache, except in case that chosen
index is clustered primary key.
index is clustered key.
*/
if ((select_limit >= table_records) &&
(tab->type == JT_ALL &&
tab->join->tables > tab->join->const_tables + 1) &&
((unsigned) best_key != table->s->primary_key ||
!table->file->primary_key_is_clustered()))
if (best_key < 0 ||
((select_limit >= table_records) &&
(tab->type == JT_ALL &&
tab->join->tables > tab->join->const_tables + 1) &&
!(table->file->index_flags(best_key, 0, 1) & HA_CLUSTERED_INDEX)))
goto use_filesort;
if (best_key >= 0)
if (table->quick_keys.is_set(best_key) && best_key != ref_key)
{
if (table->quick_keys.is_set(best_key) && best_key != ref_key)
{
key_map map;
map.clear_all(); // Force the creation of quick select
map.set_bit(best_key); // only best_key.
select->quick= 0;
select->test_quick_select(join->thd, map, 0,
join->select_options & OPTION_FOUND_ROWS ?
HA_POS_ERROR :
join->unit->select_limit_cnt,
TRUE, FALSE);
}
order_direction= best_key_direction;
/*
saved_best_key_parts is actual number of used keyparts found by the
test_if_order_by_key function. It could differ from keyinfo->key_parts,
thus we have to restore it in case of desc order as it affects
QUICK_SELECT_DESC behaviour.
*/
used_key_parts= (order_direction == -1) ?
saved_best_key_parts : best_key_parts;
key_map map;
map.clear_all(); // Force the creation of quick select
map.set_bit(best_key); // only best_key.
select->quick= 0;
select->test_quick_select(join->thd, map, 0,
join->select_options & OPTION_FOUND_ROWS ?
HA_POS_ERROR :
join->unit->select_limit_cnt,
TRUE, FALSE);
}
else
goto use_filesort;
}
order_direction= best_key_direction;
/*
saved_best_key_parts is actual number of used keyparts found by the
test_if_order_by_key function. It could differ from keyinfo->key_parts,
thus we have to restore it in case of desc order as it affects
QUICK_SELECT_DESC behaviour.
*/
used_key_parts= (order_direction == -1) ?
saved_best_key_parts : best_key_parts;
}
check_reverse_order:
DBUG_ASSERT(order_direction != 0);