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Commit 648b5474 authored by Varun Gupta's avatar Varun Gupta
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MDEV-22399: Remove multiple calls to enable and disable Handler::keyread and... 

MDEV-22399: Remove multiple calls to enable and disable Handler::keyread and perform it after the plan refinement phase is done

Introduce a function to enable keyreads for indexes and use this
function when all the decision of plan refinement phase are done.
parent 70d4e55d
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Showing with 111 additions and 71 deletions
sql/sql_select.cc
View file @ 648b5474
......@@ -1755,36 +1755,6 @@ JOIN::init_range_rowid_filters()
}
int JOIN::init_join_caches()
{
JOIN_TAB *tab;
for (tab= first_linear_tab(this, WITH_BUSH_ROOTS, WITHOUT_CONST_TABLES);
tab;
tab= next_linear_tab(this, tab, WITH_BUSH_ROOTS))
{
TABLE *table= tab->table;
if (table->file->keyread_enabled())
{
if (!(table->file->index_flags(table->file->keyread, 0, 1) & HA_CLUSTERED_INDEX))
table->mark_columns_used_by_index(table->file->keyread, table->read_set);
}
else if ((tab->read_first_record == join_read_first ||
tab->read_first_record == join_read_last) &&
!tab->filesort && table->covering_keys.is_set(tab->index) &&
!table->no_keyread)
{
table->prepare_for_keyread(tab->index, table->read_set);
}
if (tab->cache && tab->cache->init(select_options & SELECT_DESCRIBE))
revise_cache_usage(tab);
else
tab->remove_redundant_bnl_scan_conds();
}
return 0;
}
/**
global select optimisation.
......@@ -3007,8 +2977,7 @@ int JOIN::optimize_stage2()
if (make_aggr_tables_info())
DBUG_RETURN(1);
if (init_join_caches())
DBUG_RETURN(1);
init_join_cache_and_keyread();
if (init_range_rowid_filters())
DBUG_RETURN(1);
......@@ -13137,17 +13106,15 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
/* Only happens with outer joins */
tab->read_first_record= tab->type == JT_SYSTEM ? join_read_system
: join_read_const;
if (table->covering_keys.is_set(tab->ref.key) && !table->no_keyread)
table->file->ha_start_keyread(tab->ref.key);
else if ((!jcl || jcl > 4) && !tab->ref.is_access_triggered())
if (!(table->covering_keys.is_set(tab->ref.key) && !table->no_keyread) &&
(!jcl || jcl > 4) && !tab->ref.is_access_triggered())
push_index_cond(tab, tab->ref.key);
break;
case JT_EQ_REF:
tab->read_record.unlock_row= join_read_key_unlock_row;
/* fall through */
if (table->covering_keys.is_set(tab->ref.key) && !table->no_keyread)
table->file->ha_start_keyread(tab->ref.key);
else if ((!jcl || jcl > 4) && !tab->ref.is_access_triggered())
if (!(table->covering_keys.is_set(tab->ref.key) && !table->no_keyread) &&
(!jcl || jcl > 4) && !tab->ref.is_access_triggered())
push_index_cond(tab, tab->ref.key);
break;
case JT_REF_OR_NULL:
......@@ -13159,9 +13126,8 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
}
delete tab->quick;
tab->quick=0;
if (table->covering_keys.is_set(tab->ref.key) && !table->no_keyread)
table->file->ha_start_keyread(tab->ref.key);
else if ((!jcl || jcl > 4) && !tab->ref.is_access_triggered())
if (!(table->covering_keys.is_set(tab->ref.key) && !table->no_keyread) &&
(!jcl || jcl > 4) && !tab->ref.is_access_triggered())
push_index_cond(tab, tab->ref.key);
break;
case JT_ALL:
......@@ -13220,12 +13186,11 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
}
if (!table->no_keyread)
{
if (tab->select && tab->select->quick &&
tab->select->quick->index != MAX_KEY && //not index_merge
table->covering_keys.is_set(tab->select->quick->index))
table->file->ha_start_keyread(tab->select->quick->index);
else if (!table->covering_keys.is_clear_all() &&
!(tab->select && tab->select->quick))
if (!(tab->select && tab->select->quick &&
tab->select->quick->index != MAX_KEY && //not index_merge
table->covering_keys.is_set(tab->select->quick->index)) &&
(!table->covering_keys.is_clear_all() &&
!(tab->select && tab->select->quick)))
{ // Only read index tree
if (tab->loosescan_match_tab)
tab->index= tab->loosescan_key;
......@@ -13252,7 +13217,7 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
}
if (tab->select && tab->select->quick &&
tab->select->quick->index != MAX_KEY &&
!tab->table->file->keyread_enabled())
!tab->table->covering_keys.is_set(tab->select->quick->index))
push_index_cond(tab, tab->select->quick->index);
}
break;
......@@ -23604,15 +23569,6 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
bool quick_created=
(select && select->quick && select->quick!=save_quick);
/*
If ref_key used index tree reading only ('Using index' in EXPLAIN),
and best_key doesn't, then revert the decision.
*/
if (table->covering_keys.is_set(best_key) && !table->no_keyread)
table->file->ha_start_keyread(best_key);
else
table->file->ha_end_keyread();
if (!quick_created)
{
if (select) // Throw any existing quick select
......@@ -23653,7 +23609,6 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
tab->ref.key_parts= 0;
if (select_limit < table->stat_records())
tab->limit= select_limit;
table->file->ha_end_keyread();
}
}
else if (tab->type != JT_ALL || tab->select->quick)
......@@ -23754,14 +23709,6 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
{
delete save_quick;
save_quick= NULL;
/*
'delete save_quick' disabled key reads. Enable key read if the new
index is an covering key
*/
if (select->quick && !select->head->no_keyread &&
select->head->covering_keys.is_set(select->quick->index))
select->head->file->ha_start_keyread(select->quick->index);
}
if (orig_cond_saved && !changed_key)
tab->set_cond(orig_cond);
......@@ -23776,9 +23723,6 @@ test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
{
delete select->quick;
select->quick= save_quick;
if (select->quick && !select->head->no_keyread &&
select->head->covering_keys.is_set(select->quick->index))
select->head->file->ha_start_keyread(select->quick->index);
}
if (orig_cond_saved)
tab->set_cond(orig_cond);
......@@ -28593,7 +28537,6 @@ test_if_cheaper_ordering(const JOIN_TAB *tab, ORDER *order, TABLE *table,
*new_select_limit= has_limit ? best_select_limit : table_records;
if (new_used_key_parts != NULL)
*new_used_key_parts= best_key_parts;
table->file->ha_end_keyread();
DBUG_RETURN(TRUE);
}
......@@ -29327,6 +29270,103 @@ void build_notnull_conds_for_inner_nest_of_outer_join(JOIN *join,
}
/*
@brief
Initialize join cache and enable keyread
*/
void JOIN::init_join_cache_and_keyread()
{
JOIN_TAB *tab;
for (tab= first_linear_tab(this, WITH_BUSH_ROOTS, WITHOUT_CONST_TABLES);
tab;
tab= next_linear_tab(this, tab, WITH_BUSH_ROOTS))
{
TABLE *table= tab->table;
switch (tab->type) {
case JT_SYSTEM:
case JT_CONST:
case JT_FT:
case JT_UNKNOWN:
case JT_MAYBE_REF:
break;
case JT_EQ_REF:
case JT_REF_OR_NULL:
case JT_REF:
if (table->covering_keys.is_set(tab->ref.key) && !table->no_keyread)
table->file->ha_start_keyread(tab->ref.key);
break;
case JT_HASH:
case JT_ALL:
SQL_SELECT *select;
select= tab->select ? tab->select :
(tab->filesort ? tab->filesort->select : NULL);
if (select && select->quick && select->quick->index != MAX_KEY &&
table->covering_keys.is_set(select->quick->index) &&
!table->no_keyread)
table->file->ha_start_keyread(select->quick->index);
break;
case JT_HASH_NEXT:
case JT_NEXT:
if ((tab->read_first_record == join_read_first ||
tab->read_first_record == join_read_last) &&
table->covering_keys.is_set(tab->index) &&
!table->no_keyread)
{
DBUG_ASSERT(!tab->filesort);
table->file->ha_start_keyread(tab->index);
}
break;
default:
break;
/* purecov: end */
}
if (table->file->keyread_enabled())
{
/*
Here we set the read_set bitmap for all covering keys
except CLUSTERED indexes, with all the key-parts inside the key.
This is needed specifically for an index that contains virtual column.
Example:
Lets say we have this query
SELECT b FROM t1;
and the table definition is like
CREATE TABLE t1(
a varchar(10) DEFAULT NULL,
b varchar(255) GENERATED ALWAYS AS (a) VIRTUAL,
KEY key1 (b));
So we a virtual column b and an index key1 defined on the virtual
column. So if a query uses a vcol, base columns that it
depends on are automatically added to the read_set - because they're
needed to calculate the vcol.
But if we're doing keyread, vcol is taken
from the index, not calculated, and base columns do not need to be
in the read set. To ensure this we try to set the read_set to only
the key-parts of the indexes.
Another side effect of this is
Lets say you have a query
select a, b from t1
and there is an index key1 (a,b,c)
then as key1 is covering and we would have the keyread enable for
this key, so the below call will also set the read_set for column
c, which is not a problem as we read all the columns from the index
tuple.
*/
if (!(table->file->index_flags(table->file->keyread, 0, 1) & HA_CLUSTERED_INDEX))
table->mark_columns_used_by_index(table->file->keyread, table->read_set);
}
if (tab->cache && tab->cache->init(select_options & SELECT_DESCRIBE))
revise_cache_usage(tab);
else
tab->remove_redundant_bnl_scan_conds();
}
}
/**
@} (end of group Query_Optimizer)
*/
sql/sql_select.h
View file @ 648b5474
......@@ -1642,7 +1642,6 @@ class JOIN :public Sql_alloc
bool flatten_subqueries();
bool optimize_unflattened_subqueries();
bool optimize_constant_subqueries();
int init_join_caches();
bool make_range_rowid_filters();
bool init_range_rowid_filters();
bool make_sum_func_list(List<Item> &all_fields, List<Item> &send_fields,
......@@ -1826,6 +1825,7 @@ class JOIN :public Sql_alloc
bool add_having_as_table_cond(JOIN_TAB *tab);
bool make_aggr_tables_info();
bool add_fields_for_current_rowid(JOIN_TAB *cur, List<Item> *fields);
void init_join_cache_and_keyread();
};
enum enum_with_bush_roots { WITH_BUSH_ROOTS, WITHOUT_BUSH_ROOTS};
......
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