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MDEV-7317: Make an index ignorable to the optimizer

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This feature adds the functionality of ignorability for indexes.
Indexes are not ignored be default.

To control index ignorability explicitly for a new index,
use IGNORE or NOT IGNORE as part of the index definition for
CREATE TABLE, CREATE INDEX, or ALTER TABLE.

Primary keys (explicit or implicit) cannot be made ignorable.

The table INFORMATION_SCHEMA.STATISTICS get a new column named IGNORED that
would store whether an index needs to be ignored or not.
This commit is contained in:
Varun Gupta
2021-02-25 19:59:51 +05:30
parent 71d30d01aa
commit f691d9865b
108 changed files with 2541 additions and 1422 deletions
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36
mysql-test/suite/sys_vars/r/myisam_stats_method_func.result
View File

@@ -23,16 +23,16 @@ Table Op Msg_type Msg_text
test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
SHOW INDEX FROM t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
t1 1 a 1 a A 10 NULL NULL YES BTREE
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 1 a 1 a A 10 NULL NULL YES BTREE NO
INSERT INTO t1 VALUES (11);
DELETE FROM t1 WHERE a = 11;
CHECK TABLE t1;
Table Op Msg_type Msg_text
test.t1 check status OK
SHOW INDEX FROM t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
t1 1 a 1 a A 10 NULL NULL YES BTREE
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 1 a 1 a A 10 NULL NULL YES BTREE NO
'Set nulls to be equal'
SET myisam_stats_method = nulls_equal;
set @save_use_stat_tables= @@use_stat_tables;
@@ -44,16 +44,16 @@ Table Op Msg_type Msg_text
test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
SHOW INDEX FROM t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
t1 1 a 1 a A 5 NULL NULL YES BTREE
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 1 a 1 a A 5 NULL NULL YES BTREE NO
INSERT INTO t1 VALUES (11);
DELETE FROM t1 WHERE a = 11;
CHECK TABLE t1;
Table Op Msg_type Msg_text
test.t1 check status OK
SHOW INDEX FROM t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
t1 1 a 1 a A 5 NULL NULL YES BTREE
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 1 a 1 a A 5 NULL NULL YES BTREE NO
'Set nulls to be ignored'
SET myisam_stats_method = nulls_ignored;
SHOW VARIABLES LIKE 'myisam_stats_method';
@@ -73,22 +73,22 @@ Table Op Msg_type Msg_text
test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
SHOW INDEX FROM t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
t1 1 a 1 a A 2 NULL NULL YES BTREE
t1 1 a 2 b A 4 NULL NULL YES BTREE
t1 1 a 3 c A 4 NULL NULL YES BTREE
t1 1 a 4 d A 4 NULL NULL YES BTREE
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 1 a 1 a A 2 NULL NULL YES BTREE NO
t1 1 a 2 b A 4 NULL NULL YES BTREE NO
t1 1 a 3 c A 4 NULL NULL YES BTREE NO
t1 1 a 4 d A 4 NULL NULL YES BTREE NO
DELETE FROM t1;
ANALYZE TABLE t1;
Table Op Msg_type Msg_text
test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
SHOW INDEX FROM t1;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
t1 1 a 1 a A 0 NULL NULL YES BTREE
t1 1 a 2 b A 0 NULL NULL YES BTREE
t1 1 a 3 c A 0 NULL NULL YES BTREE
t1 1 a 4 d A 0 NULL NULL YES BTREE
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 1 a 1 a A 0 NULL NULL YES BTREE NO
t1 1 a 2 b A 0 NULL NULL YES BTREE NO
t1 1 a 3 c A 0 NULL NULL YES BTREE NO
t1 1 a 4 d A 0 NULL NULL YES BTREE NO
SET myisam_stats_method = DEFAULT;
set @@use_stat_tables= @save_use_stat_tables;
DROP TABLE t1;