A binary upgrade or downgrade is one that installs one version of MySQL “in place” over an existing version, without dumping and reloading tables:
Stop the server for the existing version if it is running.
Install a different version of MySQL. This is an upgrade if the new version is higher than the original version, a downgrade if the version is lower.
Start the server for the new version.
In many cases, the tables from the previous version of MySQL can be used without problem by the new version. However, sometimes changes occur that require tables or table indexes to be rebuilt, as described in this section. If you have tables that are affected by any of the issues described here, rebuild the tables or indexes as necessary using the instructions given in Section 2.4.4, “Rebuilding or Repairing Tables or Indexes”.
Table Incompatibilities
After a binary upgrade to MySQL 5.1 from a MySQL 5.0 installation
that contains ARCHIVE
tables,
accessing those tables causes the server to crash, even if you
have run mysql_upgrade or
CHECK TABLE ... FOR
UPGRADE
. To work around this problem, use
mysqldump to dump all
ARCHIVE
tables before upgrading, and
reload them into MySQL 5.1 after upgrading. The same problem
occurs for binary downgrades from MySQL 5.1 to 5.0.
Index Incompatibilities
If you perform a binary upgrade without dumping and reloading
tables, you cannot upgrade directly from MySQL 4.1 to 5.1 or
higher. This occurs due to an incompatible change in the
MyISAM
table index format in MySQL 5.0. Upgrade
from MySQL 4.1 to 5.0 and repair all MyISAM
tables. Then upgrade from MySQL 5.0 to 5.1 and check and repair
your tables.
Modifications to the handling of character sets or collations might change the character sort order, which causes the ordering of entries in any index that uses an affected character set or collation to be incorrect. Such changes result in several possible problems:
Comparison results that differ from previous results
Inability to find some index values due to misordered index entries
Misordered ORDER BY
results
Tables that CHECK TABLE
reports
as being in need of repair
The solution to these problems is to rebuild any indexes that use an affected character set or collation, either by dropping and re-creating the indexes, or by dumping and reloading the entire table. For information about rebuilding indexes, see Section 2.4.4, “Rebuilding or Repairing Tables or Indexes”.
To check whether a table has indexes that must be rebuilt, consult the following list. It indicates which versions of MySQL introduced character set or collation changes that require indexes to be rebuilt. Each entry indicates the version in which the change occurred and the character sets or collations that the change affects. If the change is associated with a particular bug report, the bug number is given.
The list applies both for binary upgrades and downgrades. For example, Bug#27877 was fixed in MySQL 5.1.24 and 5.4.0, so it applies to upgrades from versions older than 5.1.24 to 5.1.24 or newer, and to downgrades from 5.1.24 or newer to versions older than 5.1.24.
In many cases, you can use
CHECK TABLE ... FOR
UPGRADE
to identify tables for which index rebuilding is
required. (It will report: Table upgrade required. Please
do "REPAIR TABLE `tbl_name`" or dump/reload to fix it!
)
In these cases, you can also use mysqlcheck
--check-upgrade or mysql_upgrade,
which execute CHECK TABLE
. However,
the use of CHECK TABLE
applies only
after upgrades, not downgrades. Also, CHECK
TABLE
is not applicable to all storage engines. For
details about which storage engines CHECK
TABLE
supports, see Section 12.4.2.3, “CHECK TABLE
Syntax”.
Changes that cause index rebuilding to be necessary:
MySQL 5.0.48, 5.1.21 (Bug#29461)
Affects indexes for columns that use any of these character
sets: eucjpms
, euc_kr
,
gb2312
, latin7
,
macce
, ujis
Affected tables can be detected by
CHECK TABLE ...
FOR UPGRADE
as of MySQL 5.1.29, 5.4.0 (see
Bug#39585).
MySQL 5.0.48, 5.1.23 (Bug#27562)
Affects indexes that use the
ascii_general_ci
collation for columns that
contain any of these characters: '`'
GRAVE
ACCENT, '['
LEFT SQUARE BRACKET,
'\'
REVERSE SOLIDUS, ']'
RIGHT SQUARE BRACKET, '~'
TILDE
Affected tables can be detected by
CHECK TABLE ...
FOR UPGRADE
as of MySQL 5.1.29, 5.4.0 (see
Bug#39585).
MySQL 5.1.24, 5.4.0 (Bug#27877)
Affects indexes that use the
utf8_general_ci
or
ucs2_general_ci
collation for columns that
contain 'ß'
LATIN SMALL LETTER SHARP S
(German).
Affected tables can be detected by
CHECK TABLE ...
FOR UPGRADE
as of MySQL 5.1.30, 5.4.0 (see
Bug#40053).
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