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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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14
mysql-test/main/long_unique_bugs.result
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@ -82,6 +82,7 @@ Null YES
Index_type HASH
Comment
Index_comment
Ignored NO
insert into t1 values(1,1);
ERROR 23000: Duplicate entry '1' for key 'a'
DROP TABLE t1;
@ -128,6 +129,7 @@ Null
Index_type BTREE
Comment
Index_comment
Ignored NO
ALTER TABLE t1 ADD INDEX (pk);
DROP TABLE t1;
CREATE TABLE t1 (b int, a varchar(4000));
@ -280,14 +282,14 @@ DROP TABLE t1, t2;
SET binlog_row_image= FULL;
CREATE TABLE t1 (a int, b VARCHAR(1000), UNIQUE (a,b)) ENGINE=MyISAM;
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 0 a 1 a A NULL NULL NULL YES HASH
t1 0 a 2 b A NULL NULL NULL YES HASH
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t1 0 a 1 a A NULL NULL NULL YES HASH NO
t1 0 a 2 b A NULL NULL NULL YES HASH NO
CREATE TABLE t2 (a varchar(900), b VARCHAR(900), UNIQUE (a,b)) ENGINE=MyISAM;
show index from t2;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
t2 0 a 1 a A NULL NULL NULL YES HASH
t2 0 a 2 b A NULL NULL NULL YES HASH
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment Ignored
t2 0 a 1 a A NULL NULL NULL YES HASH NO
t2 0 a 2 b A NULL NULL NULL YES HASH NO
DROP TABLE t1,t2;
create temporary table tmp ( a int, b int, c blob not null, d int, e int default 0, f int, unique key (c)) engine=innodb;
create table t2 (x int);