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SET @old_instant=
(SELECT variable_value FROM information_schema.global_status
WHERE variable_name = 'innodb_instant_alter_column');
CREATE TABLE t(a INT PRIMARY KEY, b INT, c INT, d INT, e INT)
ENGINE=InnoDB;
INSERT INTO t VALUES(1,2,3,4,5);
SELECT * FROM t;
b d a c e
NULL NULL 1 NULL NULL
ALTER TABLE t DROP b, DROP c, DROP d, DROP e,
ADD COLUMN b INT, ALGORITHM=INSTANT;
ERROR 0A000: ALGORITHM=INSTANT is not supported for this operation. Try ALGORITHM=INPLACE
ALTER TABLE t CHANGE COLUMN b beta INT AFTER a, ALGORITHM=INSTANT;
ALTER TABLE t DROP e, DROP c, DROP d, ALGORITHM=INSTANT;
SELECT * FROM t;
a beta
1 NULL
ALTER TABLE t DROP COLUMN beta, ALGORITHM=INSTANT;
ALTER TABLE t ADD COLUMN b INT NOT NULL, ALGORITHM=INSTANT;
ERROR 0A000: ALGORITHM=INSTANT is not supported for this operation. Try ALGORITHM=INPLACE
SELECT variable_value-@old_instant instants
FROM information_schema.global_status
WHERE variable_name = 'innodb_instant_alter_column';
instants
256
ALTER TABLE t ADD COLUMN b INT NOT NULL;
SELECT variable_value-@old_instant instants
FROM information_schema.global_status
WHERE variable_name = 'innodb_instant_alter_column';
instants
256
SELECT * FROM t;
a b
1 0
ALTER TABLE t ADD COLUMN (c CHAR(255) NOT NULL, d BIGINT NOT NULL),
ALGORITHM=INSTANT;
UPDATE t SET b=b+1,d=d+1,c='foo';
SELECT * FROM t;
a b c d
1 1 foo 1
SELECT variable_value-@old_instant instants
FROM information_schema.global_status
WHERE variable_name = 'innodb_instant_alter_column';
instants
502
DROP TABLE t;
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