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This is a full cost-based implementation of the optimization that employs

Browse Source 
splitting technique for equi-joins of materialized derived tables/views/CTEs.
(see mdev-13369 and mdev-13389).
This commit is contained in:
Igor Babaev
2017-12-30 12:29:09 -08:00
parent 7a66e0ab8f
commit 4f0299f8b3
23 changed files with 2511 additions and 600 deletions
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80
sql/sql_select.h
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@ -73,9 +73,45 @@ typedef struct keyuse_t {
*/
uint sj_pred_no;
/*
If this is NULL than KEYUSE is always enabled.
Otherwise it points to the enabling flag for this keyuse (true <=> enabled)
*/
bool *validity_ref;
bool is_for_hash_join() { return is_hash_join_key_no(key); }
} KEYUSE;
struct KEYUSE_EXT: public KEYUSE
{
/*
This keyuse can be used only when the partial join being extended
contains the tables from this table map
*/
table_map needed_in_prefix;
/* The enabling flag for keyuses usable for splitting */
bool validity_var;
};
/// Used when finding key fields
struct KEY_FIELD {
Field *field;
Item_bool_func *cond;
Item *val; ///< May be empty if diff constant
uint level;
uint optimize;
bool eq_func;
/**
If true, the condition this struct represents will not be satisfied
when val IS NULL.
*/
bool null_rejecting;
bool *cond_guard; /* See KEYUSE::cond_guard */
uint sj_pred_no; /* See KEYUSE::sj_pred_no */
};
#define NO_KEYPART ((uint)(-1))
class store_key;
@ -201,6 +237,8 @@ class SJ_TMP_TABLE;
class JOIN_TAB_RANGE;
class AGGR_OP;
class Filesort;
struct SplM_plan_info;
class SplM_opt_info;
typedef struct st_join_table {
st_join_table() {}
@ -614,8 +652,10 @@ typedef struct st_join_table {
bool use_order() const; ///< Use ordering provided by chosen index?
bool sort_table();
bool remove_duplicates();
Item *get_splitting_cond_for_grouping_derived(THD *thd);
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);
} JOIN_TAB;
@ -920,6 +960,9 @@ typedef struct st_position
Firstmatch_picker firstmatch_picker;
LooseScan_picker loosescan_picker;
Sj_materialization_picker sjmat_picker;
/* Info on splitting plan used at this position */
SplM_plan_info *spl_plan;
} POSITION;
typedef Bounds_checked_array<Item_null_result*> Item_null_array;
@ -1053,11 +1096,13 @@ protected:
/* Support for plan reoptimization with rewritten conditions. */
enum_reopt_result reoptimize(Item *added_where, table_map join_tables,
Join_plan_state *save_to);
/* Choose a subquery plan for a table-less subquery. */
bool choose_tableless_subquery_plan();
public:
void save_query_plan(Join_plan_state *save_to);
void reset_query_plan();
void restore_query_plan(Join_plan_state *restore_from);
/* Choose a subquery plan for a table-less subquery. */
bool choose_tableless_subquery_plan();
public:
JOIN_TAB *join_tab, **best_ref;
@ -1415,9 +1460,14 @@ public:
*/
bool implicit_grouping;
bool is_for_splittable_grouping_derived;
bool with_two_phase_optimization;
ORDER *partition_list;
/* Saved execution plan for this join */
Join_plan_state *save_qep;
/* Info on splittability of the table materialized by this plan*/
SplM_opt_info *spl_opt_info;
/* Contains info on keyuses usable for splitting */
Dynamic_array<KEYUSE_EXT> *ext_keyuses_for_splitting;
JOIN_TAB *sort_and_group_aggr_tab;
@ -1465,7 +1515,10 @@ public:
need_distinct= 0;
skip_sort_order= 0;
with_two_phase_optimization= 0;
is_for_splittable_grouping_derived= 0;
save_qep= 0;
spl_opt_info= 0;
ext_keyuses_for_splitting= 0;
spl_opt_info= 0;
need_tmp= 0;
hidden_group_fields= 0; /*safety*/
error= 0;
@ -1674,10 +1727,12 @@ public:
const char *message);
JOIN_TAB *first_breadth_first_tab() { return join_tab; }
bool check_two_phase_optimization(THD *thd);
bool check_for_splittable_grouping_derived(THD *thd);
bool inject_cond_into_where(Item *injected_cond);
bool push_splitting_cond_into_derived(THD *thd, Item *cond);
bool improve_chosen_plan(THD *thd);
bool check_for_splittable_materialized();
void add_keyuses_for_splitting();
bool inject_best_splitting_cond(table_map remaining_tables);
bool fix_all_splittings_in_plan();
bool transform_in_predicates_into_in_subq(THD *thd);
private:
/**
@ -2295,6 +2350,11 @@ bool open_tmp_table(TABLE *table);
void setup_tmp_table_column_bitmaps(TABLE *table, uchar *bitmaps);
double prev_record_reads(POSITION *positions, uint idx, table_map found_ref);
void fix_list_after_tbl_changes(SELECT_LEX *new_parent, List<TABLE_LIST> *tlist);
double get_tmp_table_lookup_cost(THD *thd, double row_count, uint row_size);
double get_tmp_table_write_cost(THD *thd, double row_count, uint row_size);
void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array);
bool sort_and_filter_keyuse(THD *thd, DYNAMIC_ARRAY *keyuse,
bool skip_unprefixed_keyparts);
struct st_cond_statistic
{