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2.11.5 Preparing Your Installation for Upgrade
Before upgrading to the latest MySQL 8.0 release, ensure the upgrade readiness of your current MySQL 5.7 or MySQL 8.0 server instance by performing the preliminary checks described below. The upgrade process may fail otherwise.
The same checks and others can be performed using the MySQL Shell upgrade checker utility. For more information, see Upgrade Checker Utility.
Preliminary checks:
The following issues must not be present:
There must be no tables that use obsolete data types or functions.
In-place upgrade to MySQL 8.0 is not supported if tables contain old temporal columns in pre-5.6.4 format (
TIME
,DATETIME
, andTIMESTAMP
columns without support for fractional seconds precision). If your tables still use the old temporal column format, upgrade them before attempting an in-place upgrade to MySQL 8.0. For more information, see Server Changes.There must be no orphan
.frm
files.Triggers must not have a missing or empty definer or an invalid creation context (indicated by the
character_set_client
,collation_connection
,Database Collation
attributes displayed bySHOW TRIGGERS
or theINFORMATION_SCHEMA
TRIGGERS
table).
To check for these issues, execute this command:
mysqlcheck -u root -p --all-databases --check-upgrade
If mysqlcheck reports any errors, correct the issues.
There must be no partitioned tables that use a storage engine that does not have native partitioning support. To identify such tables, execute this query:
- SELECT TABLE_SCHEMA, TABLE_NAME
Any table reported by the query must be altered to use
InnoDB
or be made nonpartitioned. To change a table storage engine toInnoDB
, execute this statement:For information about converting
MyISAM
tables toInnoDB
, see Section 15.6.1.3, “Converting Tables from MyISAM to InnoDB”.To make a partitioned table nonpartitioned, execute this statement:
Some keywords may be reserved in MySQL 8.0 that were not reserved previously. See Section 9.3, “Keywords and Reserved Words”. This can cause words previously used as identifiers to become illegal. To fix affected statements, use identifier quoting. See Section 9.2, “Schema Object Names”.
There must be no tables in the MySQL 5.7
mysql
system database that have the same name as a table used by the MySQL 8.0 data dictionary. To identify tables with those names, execute this query:- SELECT TABLE_SCHEMA, TABLE_NAME
- (
- 'catalogs',
- 'character_sets',
- 'check_constraints',
- 'collations',
- 'column_statistics',
- 'column_type_elements',
- 'columns',
- 'dd_properties',
- 'events',
- 'foreign_key_column_usage',
- 'foreign_keys',
- 'index_column_usage',
- 'index_partitions',
- 'index_stats',
- 'indexes',
- 'parameter_type_elements',
- 'parameters',
- 'resource_groups',
- 'routines',
- 'schemata',
- 'st_spatial_reference_systems',
- 'table_partition_values',
- 'table_partitions',
- 'table_stats',
- 'tables',
- 'tablespace_files',
- 'tablespaces',
- 'triggers',
- 'view_routine_usage',
- 'view_table_usage'
- );
Any tables reported by the query must be renamed (use
RENAME TABLE
). This may also entail changes to applications that use the affected tables.There must be no tables that have foreign key constraint names longer than 64 characters. To identify tables with too-long constraint names, execute this query:
Any tables reported by the query must be altered to have constraint names no longer than 64 characters (use
ALTER TABLE
).The must be no obsolete SQL modes defined in your
sql_mode
system variable setting. Attempting to use an obsolete SQL mode will cause a startup failure on MySQL 8.0. Applications that use obsolete SQL modes should also be revised to avoid them. For information about SQL modes removed in MySQL 8.0, see Server Changes.There must be no tables or stored procedures with individual
ENUM
orSET
column elements that exceed 255 characters or 1020 bytes in length. Prior to MySQL 8.0, the maximum combined length ofENUM
orSET
column elements was 64K. In MySQL 8.0, the maximum character length of an individualENUM
orSET
column element is 255 characters, and the maximum byte length is 1020 bytes. (The 1020 byte limit supports multitibyte character sets). Before upgrading to MySQL 8.0, modify anyENUM
orSET
column elements that exceed the new limits. Failing to do so causes the upgrade to fail with an error.Before upgrading to MySQL 8.0.13 or higher, there must be no table partitions that reside in shared
InnoDB
tablespaces, which include the system tablespace and general tablespaces. Identify table partitions in shared tablespaces by queryingINFORMATION_SCHEMA
:If upgrading from MySQL 5.7, run this query:
If upgrading from an earlier MySQL 8.0 release, run this query:
Move table partitions from shared tablespaces to file-per-table tablespaces using
ALTER TABLE ... REORGANIZE PARTITION
:There must be no queries and stored program definitions from MySQL 8.0.12 or lower that use
ASC
orDESC
qualifiers forGROUP BY
clauses. Otherwise, upgrading to MySQL 8.0.13 or higher may fail, as may replicating to MySQL 8.0.13 or higher slave servers. For additional details, see SQL Changes.Your MySQL 5.7 installation must not use features that are not supported by MySQL 8.0. Any changes here are necessarily installation specific, but the following example illustrates the kind of thing to look for:
Some server startup options and system variables have been removed in MySQL 8.0. See Features Removed in MySQL 8.0, and Section 1.5, “Server and Status Variables and Options Added, Deprecated, or Removed in MySQL 8.0”. If you use any of these, an upgrade requires configuration changes.
Example: Because the data dictionary provides information about database objects, the server no longer checks directory names in the data directory to find databases. Consequently, the
--ignore-db-dir
option is extraneous and has been removed. To handle this, remove any instances of--ignore-db-dir
from your startup configuration. In addition, remove or move the named data directory subdirectories before upgrading to MySQL 8.0. (Alternatively, let the 8.0 server add those directories to the data dictionary as databases, then remove each of those databases usingDROP DATABASE
.)
Document created the 26/06/2006, last modified the 26/10/2018
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