![]() ![]() During this, we also had the limitations of earlier INSTANT ADD implementation in mind. We went back on whiteboard discussion to design something to make even the DROP COLUMN "instant". ![]() Mysql> alter table t1 drop column c2, algorithm=instant Mysql> alter table t1 add column c3 char (10) FIRST, ALGORITHM=INSTANT Mysql> alter table t1 add column c3 char (10) AFTER c1, ALGORITHM=INSTANT ĮRROR 1845 (0A000): ALGORITHM=INSTANT is not supported for this operation. Mysql> create table t1 (c1 char (10), c2 char (10)) Type '\c' to clear the current input statement. Other names may be trademarks of their respective Oracle is a registered trademark of Oracle Corporation and / or itsĪffiliates. Server version: 8.0.28 Source distributionĬopyright (c) 2000, 2022, Oracle and / or its affiliates. ![]() ADD COLUMN " had behaved in MySQL 8.0.28 (before MySQL 8.0.29 introduced the optimization, described in this article): This feature enables users to ADD new columns "INSTANTLY" to a table irrespective of table size. In other words, " don't touch any row but update the metadata only" is the core idea we came up with to solve it.Īcknowledging users requests, an early implementation of ADD COLUMN with ALGORITHM=INSTANT was added in MySQL 8.0.12. Therefore, if we could come up with a mechanism in which this "need" is omitted and we could achieve ADD/DROP COLUMN by just modifying the metadata. The root cause of problem statement is clear : " the need of modifying all existing records in the table for ADD/DROP COLUMN". And that's why o ne of the most asked feature requests from MySQL users is to have capability to ADD/DROP new/existing column(s) to/from an InnoDB Table, instantly. InnoDB, the default storage engine for MySQL, is not an exception here. And, as the number of rows in the table increases, time taken to modify all existing rows to reflect the table definition change because of ADD/DROP columns also increases. Now, if a new column is to be added or an old column is to be dropped from a table, the contents of existing rows should be changed to reflect the correct values of columns present in the table. There are no user contributed notes for this page.In databases, rows are persisted on disk and for every row, columns' value are stored on disk. Getting Started Introduction A simple tutorial Language Reference Basic syntax Types Variables Constants Expressions Operators Control Structures Functions Classes and Objects Namespaces Enumerations Errors Exceptions Fibers Generators Attributes References Explained Predefined Variables Predefined Exceptions Predefined Interfaces and Classes Predefined Attributes Context options and parameters Supported Protocols and Wrappers Security Introduction General considerations Installed as CGI binary Installed as an Apache module Session Security Filesystem Security Database Security Error Reporting User Submitted Data Hiding PHP Keeping Current Features HTTP authentication with PHP Cookies Sessions Dealing with XForms Handling file uploads Using remote files Connection handling Persistent Database Connections Command line usage Garbage Collection DTrace Dynamic Tracing Function Reference Affecting PHP's Behaviour Audio Formats Manipulation Authentication Services Command Line Specific Extensions Compression and Archive Extensions Cryptography Extensions Database Extensions Date and Time Related Extensions File System Related Extensions Human Language and Character Encoding Support Image Processing and Generation Mail Related Extensions Mathematical Extensions Non-Text MIME Output Process Control Extensions Other Basic Extensions Other Services Search Engine Extensions Server Specific Extensions Session Extensions Text Processing Variable and Type Related Extensions Web Services Windows Only Extensions XML Manipulation GUI Extensions Keyboard Shortcuts ? This help j Next menu item k Previous menu item g p Previous man page g n Next man page G Scroll to bottom g g Scroll to top g h Goto homepage g s Goto search ![]()
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