Definition of ib file set To avoid confusion, for the purposes of this discussion we define the term “ib-file set” to mean the set of operating system files that InnoDB manages as a unit. The ib-file set includes the following files: • The system...
Deviations from SQL Standards MySQL's implementation of foreign keys differs from the SQL standard in the following key respects: • If there are several rows in the parent table that have the same referenced key value, InnoDB acts in foreign key ...
Downgrading MySQL This section describes what to do to downgrade to an older MySQL version, in the unlikely case that the previous version worked better than the new one. It is always a good idea to make a backup beforehand, in case a downgrad...
DYNAMIC and COMPRESSED Row Formats This section discusses the DYNAMIC and COMPRESSED row formats for InnoDB tables. You can only create these kinds of tables when the innodb_file_format [1752] configuration option is set to Barracuda. (The Barrac...
ENUM and SET Constraints ENUM and SET columns provide an efficient way to define columns that can contain only a given set of values. See Section 11.4.4, “The ENUM Type”, and Section 11.4.5, “The SET Type”. However, before MySQL 5.0.2, ENUM and SET columns do not provide true constraints on entry...
Environment Variables This section lists all the environment variables that are used directly or indirectly by MySQL. Most of these can also be found in other places in this manual. Note that any options on the command line take precedence o...
Error Conditions for Online DDL Here are the primary reasons why an online DDL operation could fail: • If a LOCK clause specifies a low degree of locking (SHARED or NONE) that is not compatib...
Extracting the Install Archive To install MySQL manually, do the following: 1. If you are upgrading from a previous version please refer to Section 2.3.7, “Upgrading MySQL on Windows”, before beginning the upgrade process. 2. Make sure that you...
Filesort Probes The filesort probes are triggered whenever a filesort operation is applied to a table. For more information on filesort and the conditions under which it occurs, see Section 8.13.13, “ORDER BY Optimization”. filesort-start(database, table) filesort-done(status, rows) • filesort...
Further Reading More information about AUTO_INCREMENT is available here: • How to assign the AUTO_INCREMENT attribute to a column: Section 13.1.17, “CREATE TABLE Syntax”, and Section 13.1.7, “AL...
