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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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54
sql/opt_range.cc
View File

@ -1816,6 +1816,12 @@ QUICK_RANGE_SELECT::~QUICK_RANGE_SELECT()
DBUG_VOID_RETURN;
}
/*
QUICK_INDEX_SORT_SELECT works as follows:
- Do index scans, accumulate rowids in the Unique object
(Unique will also sort and de-duplicate rowids)
- Use rowids from unique to run a disk-ordered sweep
*/
QUICK_INDEX_SORT_SELECT::QUICK_INDEX_SORT_SELECT(THD *thd_param,
TABLE *table)
@ -1848,7 +1854,18 @@ QUICK_INDEX_SORT_SELECT::push_quick_back(QUICK_RANGE_SELECT *quick_sel_range)
if (head->file->primary_key_is_clustered() &&
quick_sel_range->index == head->s->primary_key)
{
/* A quick_select over a clustered primary key is handled specifically */
/*
A quick_select over a clustered primary key is handled specifically
Here we assume:
- PK columns are included in any other merged index
- Scan on the PK is disk-ordered.
(not meeting #2 will only cause performance degradation)
We could treat clustered PK as any other index, but that would
be inefficient. There is no point in doing scan on
CPK, remembering the rowid, then making rnd_pos() call with
that rowid.
*/
pk_quick_select= quick_sel_range;
DBUG_RETURN(0);
}
@ -4298,11 +4315,19 @@ double get_sweep_read_cost(const PARAM *param, ha_rows records)
DBUG_ENTER("get_sweep_read_cost");
if (param->table->file->primary_key_is_clustered())
{
/*
We are using the primary key to find the rows.
Calculate the cost for this.
*/
result= param->table->file->read_time(param->table->s->primary_key,
(uint)records, records);
}
else
{
/*
Rows will be retreived with rnd_pos(). Caluclate the expected
cost for this.
*/
double n_blocks=
ceil(ulonglong2double(param->table->file->stats.data_file_length) /
IO_SIZE);
@ -5013,7 +5038,7 @@ bool prepare_search_best_index_intersect(PARAM *param,
if ((*index_scan)->keynr == table->s->primary_key)
{
common->cpk_scan= cpk_scan= *index_scan;
break;
break;
}
}
}
@ -6187,7 +6212,6 @@ TRP_ROR_INTERSECT *get_best_ror_intersect(const PARAM *param, SEL_TREE *tree,
ROR_SCAN_INFO **cur_ror_scan;
ROR_SCAN_INFO *cpk_scan= NULL;
uint cpk_no;
bool cpk_scan_used= FALSE;
if (!(tree->ror_scans= (ROR_SCAN_INFO**)alloc_root(param->mem_root,
sizeof(ROR_SCAN_INFO*)*
@ -6199,11 +6223,20 @@ TRP_ROR_INTERSECT *get_best_ror_intersect(const PARAM *param, SEL_TREE *tree,
for (idx= 0, cur_ror_scan= tree->ror_scans; idx < param->keys; idx++)
{
ROR_SCAN_INFO *scan;
uint key_no;
if (!tree->ror_scans_map.is_set(idx))
continue;
key_no= param->real_keynr[idx];
if (key_no != cpk_no &&
param->table->file->index_flags(key_no,0,0) & HA_CLUSTERED_INDEX)
{
/* Ignore clustering keys */
tree->n_ror_scans--;
continue;
}
if (!(scan= make_ror_scan(param, idx, tree->keys[idx])))
return NULL;
if (param->real_keynr[idx] == cpk_no)
if (key_no == cpk_no)
{
cpk_scan= scan;
tree->n_ror_scans--;
@ -6289,15 +6322,14 @@ TRP_ROR_INTERSECT *get_best_ror_intersect(const PARAM *param, SEL_TREE *tree,
{
if (ror_intersect_add(intersect, cpk_scan, TRUE) &&
(intersect->total_cost < min_cost))
{
cpk_scan_used= TRUE;
intersect_best= intersect; //just set pointer here
}
}
else
cpk_scan= 0; // Don't use cpk_scan
/* Ok, return ROR-intersect plan if we have found one */
TRP_ROR_INTERSECT *trp= NULL;
if (min_cost < read_time && (cpk_scan_used || best_num > 1))
if (min_cost < read_time && (cpk_scan || best_num > 1))
{
if (!(trp= new (param->mem_root) TRP_ROR_INTERSECT))
DBUG_RETURN(trp);
@ -6316,7 +6348,7 @@ TRP_ROR_INTERSECT *get_best_ror_intersect(const PARAM *param, SEL_TREE *tree,
set_if_smaller(param->table->quick_condition_rows, best_rows);
trp->records= best_rows;
trp->index_scan_costs= intersect_best->index_scan_costs;
trp->cpk_scan= cpk_scan_used? cpk_scan: NULL;
trp->cpk_scan= cpk_scan;
DBUG_PRINT("info", ("Returning non-covering ROR-intersect plan:"
"cost %g, records %lu",
trp->read_cost, (ulong) trp->records));
@ -9511,10 +9543,10 @@ ha_rows check_quick_select(PARAM *param, uint idx, bool index_only,
bool pk_is_clustered= file->primary_key_is_clustered();
if (index_only &&
(file->index_flags(keynr, param->max_key_part, 1) & HA_KEYREAD_ONLY) &&
!(pk_is_clustered && keynr == param->table->s->primary_key))
!(file->index_flags(keynr, param->max_key_part, 1) & HA_CLUSTERED_INDEX))
*mrr_flags |= HA_MRR_INDEX_ONLY;
if (current_thd->lex->sql_command != SQLCOM_SELECT)
if (param->thd->lex->sql_command != SQLCOM_SELECT)
*mrr_flags |= HA_MRR_USE_DEFAULT_IMPL;
*bufsize= param->thd->variables.mrr_buff_size;