mirror of
https://github.com/MariaDB/server.git
synced 2025-01-16 20:12:31 +01:00
MDEV-30218: Incorrect optimization for rowid_filtering, correction
Enable use of Rowid Filter optimization with eq_ref access.
Use the following assumptions:
- Assume index-only access cost is 50% of non-index-only access cost.
- Take into account that "Eq_ref access cache" reduces the number of
lookups eq_ref access will make.
= This means the number of Rowid Filter checks is reduced also
= Eq_ref access cost is computed using that assumption (see
prev_record_reads() call), so we should use it in all cost '
computations.
This commit is contained in:
Sergei Petrunia
parent
dd24fa3063
commit
c8f9bb2718
3 changed files with 73 additions and 15 deletions
|
|
@ -336,7 +336,7 @@ WHERE l_shipdate BETWEEN '1997-01-01' AND '1997-01-31' AND
|
|||
o_totalprice between 200000 and 230000;
|
||||
id select_type table type possible_keys key key_len ref rows Extra
|
||||
1 SIMPLE lineitem range PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity i_l_shipdate 4 NULL 98 Using index condition
|
||||
1 SIMPLE orders eq_ref PRIMARY,i_o_totalprice PRIMARY 4 dbt3_s001.lineitem.l_orderkey 1 Using where
|
||||
1 SIMPLE orders eq_ref|filter PRIMARY,i_o_totalprice PRIMARY|i_o_totalprice 4|9 dbt3_s001.lineitem.l_orderkey 1 (5%) Using where; Using rowid filter
|
||||
set statement optimizer_switch='rowid_filter=on' for EXPLAIN FORMAT=JSON SELECT o_orderkey, l_linenumber, l_shipdate, o_totalprice
|
||||
FROM orders JOIN lineitem ON o_orderkey=l_orderkey
|
||||
WHERE l_shipdate BETWEEN '1997-01-01' AND '1997-01-31' AND
|
||||
|
|
@ -369,6 +369,14 @@ EXPLAIN
|
|||
"key_length": "4",
|
||||
"used_key_parts": ["o_orderkey"],
|
||||
"ref": ["dbt3_s001.lineitem.l_orderkey"],
|
||||
"rowid_filter": {
|
||||
"range": {
|
||||
"key": "i_o_totalprice",
|
||||
"used_key_parts": ["o_totalprice"]
|
||||
},
|
||||
"rows": 69,
|
||||
"selectivity_pct": 4.6
|
||||
},
|
||||
"rows": 1,
|
||||
"filtered": 4.6,
|
||||
"attached_condition": "orders.o_totalprice between 200000 and 230000"
|
||||
|
|
@ -381,7 +389,7 @@ WHERE l_shipdate BETWEEN '1997-01-01' AND '1997-01-31' AND
|
|||
o_totalprice between 200000 and 230000;
|
||||
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
|
||||
1 SIMPLE lineitem range PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity i_l_shipdate 4 NULL 98 98.00 100.00 100.00 Using index condition
|
||||
1 SIMPLE orders eq_ref PRIMARY,i_o_totalprice PRIMARY 4 dbt3_s001.lineitem.l_orderkey 1 1.00 4.60 11.22 Using where
|
||||
1 SIMPLE orders eq_ref|filter PRIMARY,i_o_totalprice PRIMARY|i_o_totalprice 4|9 dbt3_s001.lineitem.l_orderkey 1 (5%) 0.11 (10%) 4.60 100.00 Using where; Using rowid filter
|
||||
set statement optimizer_switch='rowid_filter=on' for ANALYZE FORMAT=JSON SELECT o_orderkey, l_linenumber, l_shipdate, o_totalprice
|
||||
FROM orders JOIN lineitem ON o_orderkey=l_orderkey
|
||||
WHERE l_shipdate BETWEEN '1997-01-01' AND '1997-01-31' AND
|
||||
|
|
@ -420,12 +428,25 @@ ANALYZE
|
|||
"key_length": "4",
|
||||
"used_key_parts": ["o_orderkey"],
|
||||
"ref": ["dbt3_s001.lineitem.l_orderkey"],
|
||||
"rowid_filter": {
|
||||
"range": {
|
||||
"key": "i_o_totalprice",
|
||||
"used_key_parts": ["o_totalprice"]
|
||||
},
|
||||
"rows": 69,
|
||||
"selectivity_pct": 4.6,
|
||||
"r_rows": 71,
|
||||
"r_lookups": 96,
|
||||
"r_selectivity_pct": 10.417,
|
||||
"r_buffer_size": "REPLACED",
|
||||
"r_filling_time_ms": "REPLACED"
|
||||
},
|
||||
"r_loops": 98,
|
||||
"rows": 1,
|
||||
"r_rows": 1,
|
||||
"r_rows": 0.1122,
|
||||
"r_total_time_ms": "REPLACED",
|
||||
"filtered": 4.6,
|
||||
"r_filtered": 11.224,
|
||||
"r_filtered": 100,
|
||||
"attached_condition": "orders.o_totalprice between 200000 and 230000"
|
||||
}
|
||||
}
|
||||
|
|
@ -569,7 +590,7 @@ l_quantity > 45 AND
|
|||
o_totalprice between 180000 and 230000;
|
||||
id select_type table type possible_keys key key_len ref rows Extra
|
||||
1 SIMPLE lineitem range|filter PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity,i_l_quantity i_l_shipdate|i_l_quantity 4|9 NULL 509 (12%) Using index condition; Using where; Using rowid filter
|
||||
1 SIMPLE orders eq_ref PRIMARY,i_o_totalprice PRIMARY 4 dbt3_s001.lineitem.l_orderkey 1 Using where
|
||||
1 SIMPLE orders eq_ref|filter PRIMARY,i_o_totalprice PRIMARY|i_o_totalprice 4|9 dbt3_s001.lineitem.l_orderkey 1 (9%) Using where; Using rowid filter
|
||||
set statement optimizer_switch='rowid_filter=on' for EXPLAIN FORMAT=JSON SELECT o_orderkey, l_linenumber, l_shipdate, l_quantity, o_totalprice
|
||||
FROM orders JOIN lineitem ON o_orderkey=l_orderkey
|
||||
WHERE l_shipdate BETWEEN '1997-01-01' AND '1997-06-30' AND
|
||||
|
|
@ -613,6 +634,14 @@ EXPLAIN
|
|||
"key_length": "4",
|
||||
"used_key_parts": ["o_orderkey"],
|
||||
"ref": ["dbt3_s001.lineitem.l_orderkey"],
|
||||
"rowid_filter": {
|
||||
"range": {
|
||||
"key": "i_o_totalprice",
|
||||
"used_key_parts": ["o_totalprice"]
|
||||
},
|
||||
"rows": 139,
|
||||
"selectivity_pct": 9.2667
|
||||
},
|
||||
"rows": 1,
|
||||
"filtered": 9.2667,
|
||||
"attached_condition": "orders.o_totalprice between 180000 and 230000"
|
||||
|
|
@ -626,7 +655,7 @@ l_quantity > 45 AND
|
|||
o_totalprice between 180000 and 230000;
|
||||
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
|
||||
1 SIMPLE lineitem range|filter PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity,i_l_quantity i_l_shipdate|i_l_quantity 4|9 NULL 509 (12%) 60.00 (11%) 11.69 100.00 Using index condition; Using where; Using rowid filter
|
||||
1 SIMPLE orders eq_ref PRIMARY,i_o_totalprice PRIMARY 4 dbt3_s001.lineitem.l_orderkey 1 1.00 9.27 26.67 Using where
|
||||
1 SIMPLE orders eq_ref|filter PRIMARY,i_o_totalprice PRIMARY|i_o_totalprice 4|9 dbt3_s001.lineitem.l_orderkey 1 (9%) 0.27 (25%) 9.27 100.00 Using where; Using rowid filter
|
||||
set statement optimizer_switch='rowid_filter=on' for ANALYZE FORMAT=JSON SELECT o_orderkey, l_linenumber, l_shipdate, l_quantity, o_totalprice
|
||||
FROM orders JOIN lineitem ON o_orderkey=l_orderkey
|
||||
WHERE l_shipdate BETWEEN '1997-01-01' AND '1997-06-30' AND
|
||||
|
|
@ -681,12 +710,25 @@ ANALYZE
|
|||
"key_length": "4",
|
||||
"used_key_parts": ["o_orderkey"],
|
||||
"ref": ["dbt3_s001.lineitem.l_orderkey"],
|
||||
"rowid_filter": {
|
||||
"range": {
|
||||
"key": "i_o_totalprice",
|
||||
"used_key_parts": ["o_totalprice"]
|
||||
},
|
||||
"rows": 139,
|
||||
"selectivity_pct": 9.2667,
|
||||
"r_rows": 144,
|
||||
"r_lookups": 59,
|
||||
"r_selectivity_pct": 25.424,
|
||||
"r_buffer_size": "REPLACED",
|
||||
"r_filling_time_ms": "REPLACED"
|
||||
},
|
||||
"r_loops": 60,
|
||||
"rows": 1,
|
||||
"r_rows": 1,
|
||||
"r_rows": 0.2667,
|
||||
"r_total_time_ms": "REPLACED",
|
||||
"filtered": 9.2667,
|
||||
"r_filtered": 26.667,
|
||||
"r_filtered": 100,
|
||||
"attached_condition": "orders.o_totalprice between 180000 and 230000"
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -132,7 +132,7 @@ id select_type table type possible_keys key key_len ref rows Extra
|
|||
1 PRIMARY t3 eq_ref PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX PRIMARY 34 test.t3.PARENTID 1 Using where
|
||||
1 PRIMARY t3 eq_ref PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX PRIMARY 34 test.t3.PARENTID 1 Using where
|
||||
1 PRIMARY t3 eq_ref PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX PRIMARY 34 test.t3.PARENTID 1 Using where
|
||||
1 PRIMARY t3 eq_ref PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX PRIMARY 34 test.t3.PARENTID 1 Using where
|
||||
1 PRIMARY t3 ref|filter PRIMARY,FFOLDERID_IDX,CMFLDRPARNT_IDX FFOLDERID_IDX|CMFLDRPARNT_IDX 34|35 test.t3.PARENTID 1 (29%) Using where; Using rowid filter
|
||||
drop table t1, t2, t3, t4;
|
||||
CREATE TABLE t1 (a int(10) , PRIMARY KEY (a)) Engine=InnoDB;
|
||||
INSERT INTO t1 VALUES (1),(2);
|
||||
|
|
|
|||
|
|
@ -7902,7 +7902,27 @@ best_access_path(JOIN *join,
|
|||
(s->table->file->index_flags(start_key->key,0,1) &
|
||||
HA_DO_RANGE_FILTER_PUSHDOWN))
|
||||
{
|
||||
double rows= record_count * records;
|
||||
double rows;
|
||||
if (type == JT_EQ_REF)
|
||||
{
|
||||
/*
|
||||
Treat EQ_REF access in a special way:
|
||||
1. We have no cost for index-only read. Assume its cost is 50% of
|
||||
the cost of the full read.
|
||||
|
||||
2. A regular ref access will do #record_count lookups, but eq_ref
|
||||
has "lookup cache" which reduces the number of lookups made.
|
||||
The estimation code uses prev_record_reads() call to estimate:
|
||||
|
||||
tmp = prev_record_reads(join_positions, idx, found_ref);
|
||||
|
||||
Set the effective number of rows from "tmp" here.
|
||||
*/
|
||||
keyread_tmp= tmp/ 2;
|
||||
rows= tmp;
|
||||
}
|
||||
else
|
||||
rows= record_count * records;
|
||||
|
||||
/*
|
||||
If we use filter F with selectivity s the the cost of fetching data
|
||||
|
|
@ -7945,10 +7965,6 @@ best_access_path(JOIN *join,
|
|||
we cannot use filters as the cost calculation below would cause
|
||||
tmp to become negative. The future resultion is to not limit
|
||||
cost with worst_seek.
|
||||
|
||||
We cannot use filter with JT_EQ_REF as in this case 'tmp' is
|
||||
number of rows from prev_record_read() and keyread_tmp is 0. These
|
||||
numbers are not usable with rowid filter code.
|
||||
*/
|
||||
double access_cost_factor= MY_MIN((rows - keyread_tmp) / rows, 1.0);
|
||||
if (!(records < s->worst_seeks &&
|
||||
|
|
@ -7956,7 +7972,7 @@ best_access_path(JOIN *join,
|
|||
trace_access_idx.add("rowid_filter_skipped", "worst/max seeks clipping");
|
||||
else if (access_cost_factor <= 0.0)
|
||||
trace_access_idx.add("rowid_filter_skipped", "cost_factor <= 0");
|
||||
else if (type != JT_EQ_REF)
|
||||
else
|
||||
{
|
||||
filter=
|
||||
table->best_range_rowid_filter_for_partial_join(start_key->key,
|
||||
|
|
|
|||
Loading…
Reference in a new issue