![]() Mysql> ALTER TABLE t2 ALTER COLUMN a SET DEFAULT 20, ALTER COLUMN b SET DEFAULT 200, ALGORITHM = INSTANT Mysql> # Do two operations instantly in the same statement Mysql> ALTER TABLE t2 DROP COLUMN d, ALGORITHM = INSTANT Mysql> ALTER TABLE t2 ADD COLUMN (d INT GENERATED ALWAYS AS (a + 1) VIRTUAL), ALGORITHM = INSTANT Mysql> # ADD/DROP virtual column can be instant Mysql> ALTER TABLE t2 MODIFY COLUMN c ENUM('a', 'b', 'c', 'd', 'e'), ALGORITHM=INSTANT Mysql> ALTER TABLE t2 ADD COLUMN c ENUM('a', 'b', 'c'), ALGORITHM = INSTANT Mysql> ALTER TABLE t2 ALTER COLUMN b DROP DEFAULT, ALGORITHM = INSTANT Mysql> # DROP DEFAULT to a column can be instant Mysql> ALTER TABLE t2 ALTER COLUMN b SET DEFAULT 100, ALGORITHM = INSTANT Mysql> # SET DEFAULT to a column can be instant Mysql> ALTER TABLE t1 RENAME TO t2, ALGORITHM = INSTANT Mysql> # Rename the table through ALTER TABLE can be instant ![]() Mysql> ALTER TABLE t1 DROP KEY b, ADD KEY b(b) USING BTREE, ALGORITHM = INSTANT Mysql> # Modify the index can be instant if it's a trivial change Mysql> CREATE TABLE t1 (a INT, b INT, KEY(b)) If it can not be done, then server will try INPLACE algorithm and if that can not be supported by SE, server will finally try COPY algorithm. Furthermore, if ALGORITHM is not specified at all, server will first try the DEFAULT=INSTANT algorithm. This can now be achieved by (always) specifying ALGORITHM=INSTANT, this will guarantee that either the operation is done instantly or not at all. Many users have asked us about a way to avoid time consuming schema changes. ![]() The DDL is externalized after it completes. If replication was involved, user may have to wait a even longer time for slave to be ready.This steals resources from user transactions. The DDL operation is resource hungry and puts a high demand on CPU, Memory and IO.Disk space requirements will be more than double, roughly the same size as the existing table.For large tables it can take a long time especially in a Replication setup.Up until 8.0 ( see labs release), InnoDB used to add columns to a table by rebuilding the table even for the INPLACE DDL algorithm. INPLACE DDL is mostly handled by InnoDB while COPY row by row is handled in the server layer. Prior to MySQL 5.6 the only way to do DDL was to COPY the rows one by one. MySQL 5.6 was the first release to support INPLACE DDL. We would like to thank and acknowledge this important and timely contribution by Tencent Games. This INSTANT ADD COLUMN patch was contributed by the Tencent Games DBA Team. frm files are in an arcane format that is long past its use by date. Prior to MySQL 8.0 the meta-data (data dictionary) was stored in flat files called. The move to a new transactional data dictionary in MySQL 8.0 has made this task a lot easier for us. The ability to add ADD COLUMNs instantly is the first in a series of DDL statements that we plan to do instantly. Developers constantly need to add new columns to meet the constantly changing business requirements. With ever larger and rapidly growing datasets the ability to do DDL instantly is a must have feature in any web scale database. Support my content with a Tip.Instant DDL has been one of the most requested InnoDB features for a very long time. At no additional cost to you, should you make a purchase by clicking through one of them, I will receive a commission. Receive a copy of my ebook, “10 MySQL Tips For Everyone”, absolutely free when you subscribe to the OpenLampTech newsletter.ĭisclosure: Some of this blog post’s services and product links are affiliate links. The Newsletter for PHP and MySQL Developers □ 5 Truths I’ve Come To Realize As a Self-taught Developerĭisclosure: Some of this blog post’s services and product links are affiliate links.Need hosting for your next web application or WordPress site? I highly recommend Hostinger and use them to host my niche bass fishing site.Get a handle on Google Analytics with this course by the folks over at The Content Technologist.Any of the Web Squadron Mastery Modules can help you with your online web entrepreneurial endeavor(s).My opinions are my own.Ĭheck out this article from the OpenLampTech publication page, Book Recommendation – SQL Antipatterns. Like always, just because you can do something doesn’t mean you should. Your particular goals and needs may vary. Josh Otwell has a passion to grow as a PHP Developer, SQL expert, and technical blogger/writer.ĭisclaimer: The majority of examples in this post, are performed in a personal development/learning workstation environment and should not be considered production quality or ready.
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