mariadb/mysql-test/main/long_unique_bugs_no_sp_protocol.result
Alexander Barkov 97fcafb9ec MDEV-32837 long unique does not work like unique key when using replace
write_record() when performing REPLACE has an optimization:
- if the unique violation happened in the last unique key, then do UPDATE
- otherwise, do DELETE+INSERT

This patch changes the way of detecting if this optimization
can be applied if the table has long (hash based) unique
(i.e. UNIQUE..USING HASH) constraints.

Problem:

The old condition did not take into account that
TABLE_SHARE and TABLE see long uniques differently:
- TABLE_SHARE sees as HA_KEY_ALG_LONG_HASH and HA_NOSAME
- TABLE sees as usual non-unique indexes
So the old condition could erroneously decide that the UPDATE optimization
is possible when there are still some unique hash constraints in the table.

Fix:

- If the current key is a long unique, it now works as follows:

  UPDATE can be done if the current long unique is the last
  long unique, and there are no in-engine (normal) uniques.

- For in-engine uniques nothing changes, it still works as before:

  If the current key is an in-engine (normal) unique:
  UPDATE can be done if it is the last normal unique.
2024-01-24 17:19:54 +04:00

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#
# Start of 10.5 tests
#
#
# MDEV-32837 long unique does not work like unique key when using replace
#
#
# Normal unique key + long unique key
#
CREATE TABLE t1 (a INT PRIMARY KEY, b INT, c INT, UNIQUE KEY `test` (b,c) USING HASH) ENGINE=MyISAM;
INSERT INTO t1 VALUES (1,1,1),(2,2,2);
FLUSH STATUS;
REPLACE INTO t1 VALUES (3,1,1);
SHOW STATUS WHERE Variable_name LIKE 'handler%' AND Value>0;
Variable_name Value
Handler_delete 1
Handler_read_key 2
Handler_read_rnd 1
Handler_write 1
SELECT * FROM t1 ORDER BY a;
a b c
2 2 2
3 1 1
FLUSH STATUS;
REPLACE INTO t1 VALUES (3,2,2);
SHOW STATUS WHERE Variable_name LIKE 'handler%' AND Value>0;
Variable_name Value
Handler_delete 1
Handler_read_key 3
Handler_read_rnd 2
Handler_update 1
Handler_write 1
SELECT * FROM t1;
a b c
3 2 2
DROP TABLE t1;
#
# Two long unique keys
#
CREATE TABLE t1 (a INT, b INT, c INT, UNIQUE KEY a (a) USING HASH,UNIQUE KEY `test` (b,c) USING HASH) ENGINE=MyISAM;
INSERT INTO t1 VALUES (1,1,1),(2,2,2);
FLUSH STATUS;
REPLACE INTO t1 VALUES (3,1,1);
SHOW STATUS WHERE Variable_name LIKE 'handler%' AND Value>0;
Variable_name Value
Handler_read_key 3
Handler_read_rnd 1
Handler_update 1
SELECT * FROM t1 ORDER BY a;
a b c
2 2 2
3 1 1
FLUSH STATUS;
REPLACE INTO t1 VALUES (3,2,2);
SHOW STATUS WHERE Variable_name LIKE 'handler%' AND Value>0;
Variable_name Value
Handler_delete 1
Handler_read_key 4
Handler_read_rnd 2
Handler_update 1
SELECT * FROM t1;
a b c
3 2 2
DROP TABLE t1;
#
# One long unique key
#
CREATE TABLE t1 (a INT, b INT, c INT, UNIQUE KEY `test` (b,c) USING HASH) ENGINE=MyISAM;
INSERT INTO t1 VALUES (1,1,1),(2,2,2);
FLUSH STATUS;
REPLACE INTO t1 VALUES (3,1,1);
SHOW STATUS WHERE Variable_name LIKE 'handler%' AND Value>0;
Variable_name Value
Handler_read_key 1
Handler_read_rnd 1
Handler_update 1
SELECT * FROM t1 ORDER BY a;
a b c
2 2 2
3 1 1
FLUSH STATUS;
REPLACE INTO t1 VALUES (3,2,2);
SHOW STATUS WHERE Variable_name LIKE 'handler%' AND Value>0;
Variable_name Value
Handler_read_key 1
Handler_read_rnd 1
Handler_update 1
SELECT * FROM t1;
a b c
3 1 1
3 2 2
DROP TABLE t1;
#
# End of 10.5 tests
#