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MDEV-21092,MDEV-21095,MDEV-29997: Optimizer Trace for index condition pushdown, partition pruning, exists-to-in

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Add Optimizer Tracing for:
        - Index Condition Pushdown
        - Partition Pruning
        - Exists-to-IN optimization
This commit is contained in:
Rex
2022-12-02 16:46:54 +12:00
committed by Sergei Petrunia
parent dba78f3c32
commit 07f21cfb14
9 changed files with 1062 additions and 446 deletions
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733
mysql-test/main/opt_trace.result
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File diff suppressed because it is too large Load Diff

57
mysql-test/main/opt_trace.test
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@ -932,7 +932,64 @@ explain format=json select * from three, t1 where t1.a=three.a and t1.b<5000 and
drop table three, t1;
--echo #
--echo # MDEV-21095: Index condition push down is not reflected in optimizer trace
--echo #
create table t10 (a int, b int, c int, key(a,b));
insert into t10 select seq, seq, seq from seq_1_to_10000;
explain format=json select * from t10 where a<3 and b!=5 and c<10;
set optimizer_trace='enabled=on';
select * from t10 where a<3 and b!=5 and c<10;
select json_detailed(json_extract(trace, '$**.attaching_conditions_to_tables')) as out1 from information_schema.optimizer_trace;
drop table t10;
--echo #
--echo # MDEV-21092: EXISTS to IN is not reflected in the optimizer trace
--echo #
set @@optimizer_switch = 'exists_to_in=on,in_to_exists=on,semijoin=on,materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on';
set optimizer_trace='enabled=on';
create table t1 (cn_c int, cn_n char(10), cn_a int );
create table t2 (ci_p int, ci_c int );
create table t3 (ci_p int, ci_c int );
SELECT cn_n FROM t1 WHERE (EXISTS (select 1 from t2 where ci_p > 100000 and cn_c = ci_c)
OR (cn_n LIKE 'L%') )
AND cn_a > 1000000;
select json_detailed(json_extract(trace, '$.steps[*].join_optimization[0].steps[0].transformation')) from information_schema.optimizer_trace;
drop table t1, t2, t3;
--echo #
--echo # MDEV-29997 Partition Pruning not included in optimizer tracing
--echo #
--source include/have_partition.inc
create table t2 (a int, b int) partition by hash(a) partitions 10;
create table t3 (a int, b int) partition by hash(a) partitions 10;
INSERT INTO t2 SELECT seq, seq from seq_1_to_10;
INSERT INTO t3 SELECT seq, seq from seq_1_to_10;
set optimizer_trace='enabled=on';
explain partitions select * from t2,t3 where t2.a in (2,3,4) and t3.a in (4,5);
select json_detailed(json_extract(trace, '$**.prune_partitions')) from information_schema.optimizer_trace;
drop table t2,t3;
create table t1 (
a int
) partition by range (a)
( partition p0 values less than(10),
partition p1 values less than (20),
partition p2 values less than (25)
);
insert into t1 values (5),(15),(22);
explain select * from t1 where a = 28;
select json_detailed(json_extract(trace, '$**.prune_partitions')) from information_schema.optimizer_trace;
drop table t1;
set @@optimizer_switch= @save_optimizer_switch;
set @@use_stat_tables= @save_use_stat_tables;
set @@histogram_size= @save_histogram_size;
set @@optimizer_use_condition_selectivity= @save_optimizer_use_condition_selectivity;

16
mysql-test/main/opt_trace_index_merge.result
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@ -256,16 +256,24 @@ explain select * from t1 where a=1 or b=1 {
"resulting_condition": "t1.a = 1 or t1.b = 1"
}
},
{
"make_join_readinfo": [
{
"table": "t1",
"index_condition": "t1.a = 1 or t1.b = 1"
}
]
}
]
}
},
{
"attaching_conditions_to_tables": {
"attached_conditions_computation": [],
"attached_conditions_summary": [
{
"table": "t1",
"attached": "t1.a = 1 or t1.b = 1"
}
]
}
"attached_condition": "t1.a = 1 or t1.b = 1"
}
]
}

17
mysql-test/main/opt_trace_index_merge_innodb.result
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@ -255,16 +255,25 @@ explain select * from t1 where pk1 != 0 and key1 = 1 {
"resulting_condition": "t1.key1 = 1 and t1.pk1 <> 0"
}
},
{
"make_join_readinfo": [
{
"table": "t1",
"index_condition": null
}
]
}
]
}
},
{
"attaching_conditions_to_tables": {
"attached_conditions_computation": [],
"attached_conditions_summary": [
{
"table": "t1",
"attached": "t1.pk1 <> 0"
}
]
}
"attached_condition": null,
"index_condition": "t1.pk1 <> 0"
}
]
}

32
mysql-test/main/opt_trace_security.result
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@ -132,16 +132,24 @@ select * from db1.t1 {
"rows": 3,
"cost": 0.010504815
},
{
"make_join_readinfo": [
{
"table": "t1",
"index_condition": null
}
]
}
]
}
},
{
"attaching_conditions_to_tables": {
"attached_conditions_computation": [],
"attached_conditions_summary": [
{
"table": "t1",
"attached": null
}
]
}
"attached_condition": null
}
]
}
@ -271,16 +279,24 @@ select * from db1.v1 {
"rows": 3,
"cost": 0.010504815
},
{
"make_join_readinfo": [
{
"table": "t1",
"index_condition": null
}
]
}
]
}
},
{
"attaching_conditions_to_tables": {
"attached_conditions_computation": [],
"attached_conditions_summary": [
{
"table": "t1",
"attached": null
}
]
}
"attached_condition": null
}
]
}

24
sql/item.cc
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@ -42,6 +42,7 @@
// RESOLVED_AGAINST_ALIAS, ...
#include "sql_expression_cache.h"
#include "sql_lex.h" // empty_clex_str
#include "my_json_writer.h" // for dbug_print_opt_trace()
const String my_null_string("NULL", 4, default_charset_info);
const String my_default_string("DEFAULT", 7, default_charset_info);
@ -10887,6 +10888,29 @@ const char *dbug_print_item(Item *item)
return "Couldn't fit into buffer";
}
/*
Return the optimizer trace collected so far for the current thread.
*/
const char *dbug_print_opt_trace()
{
if (current_thd)
{
if (current_thd->opt_trace.is_started())
{
String *s= const_cast<String *>(current_thd->opt_trace
.get_current_json()->output.get_string());
return s->c_ptr();
}
else
return "Trace empty";
}
else
return "No Thread";
}
const char *dbug_print_select(SELECT_LEX *sl)
{
char *buf= dbug_item_print_buf;

9
sql/item_subselect.cc
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@ -42,6 +42,7 @@
#include "sql_parse.h" // check_stack_overrun
#include "sql_cte.h"
#include "sql_test.h"
#include "opt_trace.h"
double get_post_group_estimate(JOIN* join, double join_op_rows);
@ -3342,6 +3343,14 @@ bool Item_exists_subselect::exists2in_processor(void *opt_arg)
set possible optimization strategies
*/
in_subs->emb_on_expr_nest= emb_on_expr_nest;
{
OPT_TRACE_TRANSFORM(thd, trace_wrapper, trace_transform,
in_subs->get_select_lex()->select_number,
"EXISTS (SELECT)", "IN (SELECT)");
trace_transform.add( "upper_not", ( upper_not?true:false ) );
}
res= check_and_do_in_subquery_rewrites(join);
first_select->join->prepare_stage2();

14
sql/opt_range.cc
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@ -4198,6 +4198,20 @@ end:
table->all_partitions_pruned_away= true;
retval= TRUE;
}
if (unlikely(thd->trace_started()))
{
String parts;
String_list parts_list;
make_used_partitions_str(thd->mem_root, prune_param.part_info, &parts,
parts_list);
Json_writer_object trace_wrapper(thd);
Json_writer_object trace_prune(thd, "prune_partitions");
trace_prune.add_table_name(table);
trace_prune.add("used_partitions", parts.c_ptr());
}
DBUG_RETURN(retval);
}

82
sql/sql_select.cc
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@ -349,6 +349,8 @@ static void fix_items_after_optimize(THD *thd, SELECT_LEX *select_lex);
static void optimize_rownum(THD *thd, SELECT_LEX_UNIT *unit, Item *cond);
static bool process_direct_rownum_comparison(THD *thd, SELECT_LEX_UNIT *unit,
Item *cond);
void trace_attached_conditions(THD *thd, JOIN *join);
void trace_join_readinfo(THD *thd, JOIN *join);
#ifndef DBUG_OFF
@ -3137,6 +3139,8 @@ int JOIN::optimize_stage2()
if (make_join_readinfo(this, select_opts_for_readinfo, no_jbuf_after))
DBUG_RETURN(1);
trace_join_readinfo(thd, this);
/* Perform FULLTEXT search before all regular searches */
if (!(select_options & SELECT_DESCRIBE))
if (init_ftfuncs(thd, select_lex, MY_TEST(order)))
@ -5112,6 +5116,8 @@ mysql_select(THD *thd, TABLE_LIST *tables, List<Item> &fields, COND *conds,
goto err; // 1
}
trace_attached_conditions(thd, join);
if (thd->lex->describe & DESCRIBE_EXTENDED)
{
join->conds_history= join->conds;
@ -13073,10 +13079,7 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
/*
Step #2: Extract WHERE/ON parts
*/
Json_writer_object trace_wrapper(thd);
Json_writer_object trace_conditions(thd, "attaching_conditions_to_tables");
Json_writer_array trace_attached_comp(thd,
"attached_conditions_computation");
uint i;
for (i= join->top_join_tab_count - 1; i >= join->const_tables; i--)
{
@ -13644,23 +13647,6 @@ make_join_select(JOIN *join,SQL_SELECT *select,COND *cond)
i++;
}
if (unlikely(thd->trace_started()))
{
trace_attached_comp.end();
Json_writer_array trace_attached_summary(thd,
"attached_conditions_summary");
for (tab= first_depth_first_tab(join); tab;
tab= next_depth_first_tab(join, tab))
{
if (!tab->table)
continue;
Item *const cond = tab->select_cond;
Json_writer_object trace_one_table(thd);
trace_one_table.
add_table_name(tab).
add("attached", cond);
}
}
}
DBUG_RETURN(0);
}
@ -31920,6 +31906,60 @@ bool JOIN::transform_all_conds_and_on_exprs_in_join_list(
}
void trace_attached_conditions(THD *thd, JOIN *join)
{
if (!unlikely(thd->trace_started()))
return;
Json_writer_object trace_wrapper(thd);
Json_writer_object trace_conditions(thd, "attaching_conditions_to_tables");
Json_writer_array trace_attached_comp(thd,
"attached_conditions_computation");
JOIN_TAB *tab;
trace_attached_comp.end();
Json_writer_array trace_attached_summary(thd,
"attached_conditions_summary");
for (tab= first_depth_first_tab(join);
tab;
tab= next_depth_first_tab(join, tab))
{
if (!tab->table)
continue;
Item *const remaining_cond = tab->select_cond;
Item *const idx_cond = tab->table->file->pushed_idx_cond;
Json_writer_object trace_one_table(thd);
trace_one_table.add_table_name(tab);
trace_one_table.add("attached_condition", remaining_cond);
if (idx_cond)
trace_one_table.add("index_condition", idx_cond);
}
}
void trace_join_readinfo(THD *thd, JOIN *join)
{
if (!unlikely(thd->trace_started()))
return;
Json_writer_object trace_wrapper(thd);
Json_writer_array trace_conditions(thd, "make_join_readinfo");
JOIN_TAB *tab;
for (tab= first_linear_tab(join, WITH_BUSH_ROOTS, WITHOUT_CONST_TABLES);
tab;
tab= next_linear_tab(join, tab, WITH_BUSH_ROOTS))
{
Json_writer_object trace_one_table(thd);
trace_one_table.add_table_name(tab);
trace_one_table.add("index_condition", tab->select_cond);
}
}
/**
@} (end of group Query_Optimizer)
*/