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MDEV-26301 Split optimization refills temporary table too many times

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This patch optimizes the number of refills for the lateral derived table
to which a materialized derived table subject to split optimization is
is converted. This optimized number of refills is now considered as the
expected number of refills of the materialized derived table when searching
for the best possible splitting of the table.
This commit is contained in:
Igor Babaev
2023-05-02 23:17:07 -07:00
committed by Oleksandr Byelkin
parent ec79f37718
commit ce7ffe61d8
5 changed files with 910 additions and 32 deletions
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31
sql/sql_select.h
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@ -394,6 +394,8 @@ typedef struct st_join_table {
*/
bool idx_cond_fact_out;
bool use_join_cache;
/* TRUE <=> it is prohibited to join this table using join buffer */
bool no_forced_join_cache;
uint used_join_cache_level;
ulong join_buffer_size_limit;
JOIN_CACHE *cache;
@ -520,6 +522,16 @@ typedef struct st_join_table {
bool preread_init_done;
/* true <=> split optimization has been applied to this materialized table */
bool is_split_derived;
/*
Bitmap of split materialized derived tables that can be filled just before
this join table is to be joined. All parameters of the split derived tables
belong to tables preceding this join table.
*/
table_map split_derived_to_update;
/*
Cost info to the range filter used when joining this join table
(Defined when the best join order has been already chosen)
@ -680,9 +692,10 @@ typedef struct st_join_table {
void partial_cleanup();
void add_keyuses_for_splitting();
SplM_plan_info *choose_best_splitting(double record_count,
table_map remaining_tables);
bool fix_splitting(SplM_plan_info *spl_plan, table_map remaining_tables,
SplM_plan_info *choose_best_splitting(uint idx,
table_map remaining_tables,
table_map *spl_pd_boundary);
bool fix_splitting(SplM_plan_info *spl_plan, table_map excluded_tables,
bool is_const_table);
} JOIN_TAB;
@ -947,9 +960,21 @@ public:
*/
KEYUSE *key;
/* Cardinality of current partial join ending with this position */
double partial_join_cardinality;
/* Info on splitting plan used at this position */
SplM_plan_info *spl_plan;
/*
If spl_plan is NULL the value of spl_pd_boundary is 0. Otherwise
spl_pd_boundary contains the bitmap of the table from the current
partial join ending at this position that starts the sub-sequence of
tables S from which no conditions are allowed to be used in the plan
spl_plan for the split table joined at this position.
*/
table_map spl_pd_boundary;
/* Cost info for the range filter used at this position */
Range_rowid_filter_cost_info *range_rowid_filter_info;