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Commit 00675d25 authored by Sergei Petrunia's avatar Sergei Petrunia
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MDEV-9750: Quick memory exhaustion with 'extended_keys=on' ... 

Part #3: Introduce a user-visible @@optimizer_max_sel_arg_weight
to control the optimization.
parent 805fcc4c
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Showing with 138 additions and 6 deletions
mysql-test/main/range.result
View file @ 00675d25
......@@ -3146,6 +3146,9 @@ kp4 int,
key key1(kp1, kp2, kp3,kp4)
);
insert into t1 values (1,1,1,1),(2,2,2,2),(3,3,3,3);
show variables like 'optimizer_max_sel_arg_weight';
Variable_name Value
optimizer_max_sel_arg_weight 32000
set @tmp_9750=@@optimizer_trace;
set optimizer_trace=1;
explain select * from t1 where
......@@ -3179,6 +3182,94 @@ left(@json, 500)
"(1,1,6) <= (kp1,kp2,kp3) <= (1,1,6)",
"(1,1,7) <= (kp1,kp2,kp3) <= (1,1,7)",
"
## Repeat the above with low max_weight:
set @tmp9750_weight=@@optimizer_max_sel_arg_weight;
set optimizer_max_sel_arg_weight=20;
explain select * from t1 where
kp1 in (1,2,3,4,5,6,7,8,9,10) and
kp2 in (1,2,3,4,5,6,7,8,9,10) and
kp3 in (1,2,3,4,5,6,7,8,9,10) and
kp4 in (1,2,3,4,5,6,7,8,9,10)
;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index key1 key1 20 NULL 3 Using where; Using index
set @json= (select json_detailed(JSON_EXTRACT(trace, '$**.range_scan_alternatives'))
from information_schema.optimizer_trace);
select left(@json, 500);
left(@json, 500)
[
[
{
"index": "key1",
"ranges":
[
"(1) <= (kp1) <= (1)",
"(2) <= (kp1) <= (2)",
"(3) <= (kp1) <= (3)",
"(4) <= (kp1) <= (4)",
"(5) <= (kp1) <= (5)",
"(6) <= (kp1) <= (6)",
"(7) <= (kp1) <= (7)",
"(8) <= (kp1) <= (8)",
"(9) <= (kp1) <= (9)",
"(10) <= (kp1) <= (10)"
## Repeat the above with a bit higher max_weight:
set @tmp9750_weight=@@optimizer_max_sel_arg_weight;
set optimizer_max_sel_arg_weight=120;
explain select * from t1 where
kp1 in (1,2,3,4,5,6,7,8,9,10) and
kp2 in (1,2,3,4,5,6,7,8,9,10) and
kp3 in (1,2,3,4,5,6,7,8,9,10) and
kp4 in (1,2,3,4,5,6,7,8,9,10)
;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index key1 key1 20 NULL 3 Using where; Using index
set @json= (select json_detailed(JSON_EXTRACT(trace, '$**.range_scan_alternatives'))
from information_schema.optimizer_trace);
select left(@json, 1500);
left(@json, 1500)
[
[
{
"index": "key1",
"ranges":
[
"(1,1) <= (kp1,kp2) <= (1,1)",
"(1,2) <= (kp1,kp2) <= (1,2)",
"(1,3) <= (kp1,kp2) <= (1,3)",
"(1,4) <= (kp1,kp2) <= (1,4)",
"(1,5) <= (kp1,kp2) <= (1,5)",
"(1,6) <= (kp1,kp2) <= (1,6)",
"(1,7) <= (kp1,kp2) <= (1,7)",
"(1,8) <= (kp1,kp2) <= (1,8)",
"(1,9) <= (kp1,kp2) <= (1,9)",
"(1,10) <= (kp1,kp2) <= (1,10)",
"(2,1) <= (kp1,kp2) <= (2,1)",
"(2,2) <= (kp1,kp2) <= (2,2)",
"(2,3) <= (kp1,kp2) <= (2,3)",
"(2,4) <= (kp1,kp2) <= (2,4)",
"(2,5) <= (kp1,kp2) <= (2,5)",
"(2,6) <= (kp1,kp2) <= (2,6)",
"(2,7) <= (kp1,kp2) <= (2,7)",
"(2,8) <= (kp1,kp2) <= (2,8)",
"(2,9) <= (kp1,kp2) <= (2,9)",
"(2,10) <= (kp1,kp2) <= (2,10)",
"(3,1) <= (kp1,kp2) <= (3,1)",
"(3,2) <= (kp1,kp2) <= (3,2)",
"(3,3) <= (kp1,kp2) <= (3,3)",
"(3,4) <= (kp1,kp2) <= (3,4)",
"(3,5) <= (kp1,kp2) <= (3,5)",
"(3,6) <= (kp1,kp2) <= (3,6)",
"(3,7) <= (kp1,kp2) <= (3,7)",
"(3,8) <= (kp1,kp2) <= (3,8)",
"(3,9) <= (kp1,kp2) <= (3,9)",
"(3,10) <= (kp1,kp2
set optimizer_max_sel_arg_weight= @tmp9750_weight;
set optimizer_trace=@tmp_9750;
drop table t1;
set global innodb_stats_persistent= @innodb_stats_persistent_save;
......
mysql-test/main/range.test
View file @ 00675d25
......@@ -2133,6 +2133,8 @@ create table t1 (
insert into t1 values (1,1,1,1),(2,2,2,2),(3,3,3,3);
show variables like 'optimizer_max_sel_arg_weight';
# 20 * 20 * 20 *20 = 400*400 = 160,000 ranges
set @tmp_9750=@@optimizer_trace;
set optimizer_trace=1;
......@@ -2150,9 +2152,37 @@ set @json= (select json_detailed(JSON_EXTRACT(trace, '$**.range_scan_alternative
--echo # to keep the number of ranges at manageable level:
select left(@json, 500);
--echo ## Repeat the above with low max_weight:
set @tmp9750_weight=@@optimizer_max_sel_arg_weight;
set optimizer_max_sel_arg_weight=20;
explain select * from t1 where
kp1 in (1,2,3,4,5,6,7,8,9,10) and
kp2 in (1,2,3,4,5,6,7,8,9,10) and
kp3 in (1,2,3,4,5,6,7,8,9,10) and
kp4 in (1,2,3,4,5,6,7,8,9,10)
;
set @json= (select json_detailed(JSON_EXTRACT(trace, '$**.range_scan_alternatives'))
from information_schema.optimizer_trace);
select left(@json, 500);
--echo ## Repeat the above with a bit higher max_weight:
set @tmp9750_weight=@@optimizer_max_sel_arg_weight;
set optimizer_max_sel_arg_weight=120;
explain select * from t1 where
kp1 in (1,2,3,4,5,6,7,8,9,10) and
kp2 in (1,2,3,4,5,6,7,8,9,10) and
kp3 in (1,2,3,4,5,6,7,8,9,10) and
kp4 in (1,2,3,4,5,6,7,8,9,10)
;
set @json= (select json_detailed(JSON_EXTRACT(trace, '$**.range_scan_alternatives'))
from information_schema.optimizer_trace);
select left(@json, 1500);
set optimizer_max_sel_arg_weight= @tmp9750_weight;
set optimizer_trace=@tmp_9750;
drop table t1;
set global innodb_stats_persistent= @innodb_stats_persistent_save;
set global innodb_stats_persistent_sample_pages=
@innodb_stats_persistent_sample_pages_save;
sql/opt_range.cc
View file @ 00675d25
......@@ -415,7 +415,7 @@ static bool null_part_in_key(KEY_PART *key_part, const uchar *key,
uint length);
static bool is_key_scan_ror(PARAM *param, uint keynr, uint8 nparts);
static SEL_ARG *enforce_sel_arg_weight_limit(SEL_ARG *sel_arg);
static SEL_ARG *enforce_sel_arg_weight_limit(THD *thd, SEL_ARG *sel_arg);
#include "opt_range_mrr.cc"
......@@ -9971,7 +9971,8 @@ uint SEL_ARG::verify_weight()
static SEL_ARG *key_or_with_limit(RANGE_OPT_PARAM *param,
SEL_ARG *key1, SEL_ARG *key2)
{
SEL_ARG *res= enforce_sel_arg_weight_limit(key_or(param, key1, key2));
SEL_ARG *res= enforce_sel_arg_weight_limit(param->thd, key_or(param,
key1, key2));
#ifndef DBUG_OFF
if (res)
res->verify_weight();
......@@ -9984,7 +9985,9 @@ static SEL_ARG *key_and_with_limit(RANGE_OPT_PARAM *param,
SEL_ARG *key1, SEL_ARG *key2,
uint clone_flag)
{
SEL_ARG *res= enforce_sel_arg_weight_limit(key_and(param, key1, key2, clone_flag));
SEL_ARG *res= enforce_sel_arg_weight_limit(param->thd, key_and(param, key1,
key2,
clone_flag));
#ifndef DBUG_OFF
if (res)
res->verify_weight();
......@@ -10770,14 +10773,15 @@ void prune_sel_arg_graph(SEL_ARG *sel_arg, uint max_part)
limit.
*/
SEL_ARG *enforce_sel_arg_weight_limit(SEL_ARG *sel_arg)
SEL_ARG *enforce_sel_arg_weight_limit(THD *thd, SEL_ARG *sel_arg)
{
if (!sel_arg || sel_arg->type != SEL_ARG::KEY_RANGE)
if (!sel_arg || sel_arg->type != SEL_ARG::KEY_RANGE ||
!thd->variables.optimizer_max_sel_arg_weight)
return sel_arg;
while (1)
{
if (sel_arg->weight <= SEL_ARG::MAX_WEIGHT)
if (sel_arg->weight <= thd->variables.optimizer_max_sel_arg_weight)
return sel_arg;
uint max_part= sel_arg->get_max_key_part();
......
sql/sql_class.h
View file @ 00675d25
......@@ -766,6 +766,7 @@ typedef struct system_variables
uint column_compression_threshold;
uint column_compression_zlib_level;
uint in_subquery_conversion_threshold;
ulong optimizer_max_sel_arg_weight;
ulonglong max_rowid_filter_size;
vers_asof_timestamp_t vers_asof_timestamp;
......
sql/sys_vars.cc
View file @ 00675d25
......@@ -6367,6 +6367,12 @@ static Sys_var_uint Sys_in_subquery_conversion_threshold(
SESSION_VAR(in_subquery_conversion_threshold), CMD_LINE(REQUIRED_ARG),
VALID_RANGE(0, UINT_MAX), DEFAULT(IN_SUBQUERY_CONVERSION_THRESHOLD), BLOCK_SIZE(1));
static Sys_var_ulong Sys_optimizer_max_sel_arg_weight(
"optimizer_max_sel_arg_weight",
"The maximum weight of the SEL_ARG graph. Set to 0 for no limit",
SESSION_VAR(optimizer_max_sel_arg_weight), CMD_LINE(REQUIRED_ARG),
VALID_RANGE(0, ULONG_MAX), DEFAULT(SEL_ARG::MAX_WEIGHT), BLOCK_SIZE(1));
static Sys_var_enum Sys_secure_timestamp(
"secure_timestamp", "Restricts direct setting of a session "
"timestamp. Possible levels are: YES - timestamp cannot deviate from "
......
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