Answer Diff [120]
<<toc>>
¶
== MariaDB is a binary drop in replacement for MySQL ¶
¶
For all practical purposes, MariaDB is a binary drop in replacement of the same ¶
MySQL version (for example MySQL 5.1 -> MariaDB 5.1, MariaDB 5.2 & MariaDB 5.3 ¶
are compatible. MySQL 5.5 will be compatible with MariaDB 5.5). What this ¶
means is that: ¶
¶
* Data and table definition files (.frm) files are binary compatible. ¶
* All client APIs, protocols and structs are identical. ¶
* All filenames, binaries, paths, ports, sockets, and etc... should be the ¶
same. ¶
* All MySQL connectors (PHP, Perl, Python, Java, .NET, MyODBC, Ruby, MySQL C ¶
connector etc) work unchanged with MariaDB. ¶
** There are some [[installation-issues-with-php5|installation issues with PHP5]] ¶
that you should be aware of (a bug in how the old PHP5 client checks library ¶
compatibility). ¶
* The ##mysql-client## package also works with MariaDB server. ¶
¶
This means that for most cases, you can just uninstall MySQL and ¶
[[getting-installing-and-upgrading-mariadb|install MariaDB]] and you are good ¶
to go. (No need to convert any datafiles if you use same main version, like ¶
5.1). ¶
¶
We do monthly merges with the MySQL code base to ensure we keep up our ¶
compatibility and get any and all features and bug fixes Oracle adds. ¶
¶
We have also done a lot of work on the upgrade scripts to the point where it is now easier to ¶
[[upgrading-to-mariadb-from-mysql|upgrade from MySQL 5.0 to MariaDB 5.1]] than ¶
from MySQL 5.0 to MySQL 5.1. ¶
¶
That said, MariaDB has a lot of ¶
[[mariadb-versus-mysql-features|new options, extension, storage engines and bug fixes]] ¶
that are not in MySQL. You can find the feature set for the different MariaDB ¶
versions on the [[what-is-in-the-different-mariadb-releases|What is in the different MariaDB Releases]] page. ¶
¶
See also [[mariadb-versus-mysql-features | MariaDB versus MySQL - Features]]. ¶
¶
== Incompatibilities between MariaDB 5.1 and MySQL 5.1 ¶
¶
In some few cases MariaDB has to be incompatible to allow MariaDB to provide ¶
more and better information than MySQL. ¶
¶
Here is the list of all known user level incompatibilities you may see ¶
when using MariaDB 5.1 instead of MySQL 5.1. ¶
¶
* The installation package names starts with MariaDB instead of MySQL. ¶
* Timings may be different as MariaDB is in many cases faster than MySQL. ¶
* mysqld in MariaDB reads also the <<code>>[mariadb]<</code>> sections of your ¶
my.cnf files. ¶
* You can't use a binary only storage engine library with MariaDB if it's not ¶
compiled for exactly the same MariaDB version. (This is because the server ¶
internal structure THD is different between MySQL and MariaDB. This is common ¶
also between different MySQL versions). This should not be a problem as most ¶
people don't load new storage engines and MariaDB comes with more ¶
[[mariadb-storage-engines|more storage engines]] than MySQL. ¶
* ##CHECKSUM TABLE## may give different result as MariaDB doesn't ignore NULL's ¶
in the columns as MySQL 5.1 does (Future MySQL versions should calculate ¶
checksums the same way as MariaDB). You can get the 'old style' checksum in ¶
MariaDB by starting mysqld with the <<code>>--old<</code>> option. Note however that that ¶
the MyISAM and Aria storage engines in MariaDB are using the new checksum ¶
internally, so if you are using <<code>>--old<</code>>, the ##CHECKSUM## command will be ¶
slower as it needs to calculate the checksum row by row. ¶
* The slow query log has ¶
[[slow-query-log-extended-statistics|more information]] about the query, ¶
which may be a problem if you have a script which parses the slow query log. ¶
* MariaDB by default takes a bit more memory than MySQL because we have by ¶
default enabled the [[aria-formerly-known-as-maria|Aria storage engine]] for ¶
handling internal temporary tables. If you need MariaDB to take very little ¶
memory (at the expense of performance), you can set the value ¶
of ##aria_pagecache_buffer_size## to ##1M## (the default is ##128M##). ¶
* If you are using [[mysqld-startup-options|new command options]], ¶
[[mariadb-versus-mysql-features|new features of MariaDB]] or ¶
[[mariadb-storage-engines|new storage engines]], you can't move easily back ¶
and forth between MySQL and MariaDB anymore. ¶
¶
== Incompatibilities between MariaDB 5.2 and MySQL 5.1 ¶
¶
The list is the same as between MariaDB 5.1 and MySQL 5.1. ¶
¶
For all practical purposes, MariaDB 5.2 is a drop in replacement for MariaDB 5.1 and MySQL 5.1. ¶
¶
== Incompatibilities between MariaDB 5.3 and MySQL 5.1 and MariaDB 5.2 ¶
¶
* A few error messages related to wrong conversions are different as MariaDB ¶
provides more information in the message about what went wrong. ¶
* Error numbers for MariaDB specific errors has been moved to start from 1900 ¶
to not conflict with MySQL errors. ¶
* Microseconds now works in all contexts; MySQL did, in some contexts, lose the ¶
microsecond part from datetime and time. ¶
* The old <<code>>--maria-<</code>> startup options are removed. You should use ¶
the <<code>>--aria-<</code>> prefix instead. (MariaDB 5.2 supports both <<code>>--maria-<</code>> ¶
and <<code>>--aria-<</code>>) ¶
* ##[[show-processlist|SHOW PROCESSLIST]]## has an extra ##Progress## column ¶
which shows progress for some commands. You can disable it by ¶
starting ##mysqld## with the <<code>>--old<</code>> flag. ¶
* ##INFORMATION_SCHEMA.PROCESSLIST## has three new columns for progress ¶
reporting: ##STAGE##, ##MAX_STAGE##, and ##PROGRESS##. ¶
* [[comment-syntax|Long comments]] which start with <<code>>/*M!<</code>> ¶
or <<code>>/*M!#####<</code>> are executed. ¶
* If you use <<code>>max_user_connections=0<</code>> (which means any number ¶
of connections) when starting mysqld, you can't change the global variable ¶
anymore while mysqld remains running. This is because when mysqld is started ¶
with <<code>>max_user_connections=0<</code>> it does not allocate counting ¶
structures (which also involve a mutex for each connection). This would lead ¶
to wrong counters if you later changed the variable. If you want to be able ¶
to change this variable at runtime, set it to a high value at startup. ¶
* You can set <<code>>max_user_connections<</code>> (both the global variable ¶
and the ##GRANT## option) to ##-1## to stop users from connecting to the ¶
server. The global <<code>>max_user_connections<</code>> variable does not ¶
affect users with the <<code>>SUPER<</code>> privilege. ¶
* The [[ignore|IGNORE]] directive does not ignore all errors (like fatal errors), only things that are safe to ignore. ¶
¶
== Old, unsupported configuration options ¶
¶
If you are using any of the following options in your ##/etc/my.cnf## or other ¶
##my.cnf## file you should remove them. This is also true for MySQL 5.1 or ¶
newer: ¶
¶
* ##skip-bdb## ¶
¶
== Replacing a MySQL RPM == ¶
¶
If you uninstalled a MySQL RPM to install MariaDB, note that the MySQL RPM on ¶
uninstall renames ##/etc/my.cnf## to ##/etc/my.cnf.rpmsave##. ¶
¶
After installing MariaDB you should do the following to restore your old ¶
configuration options: ¶
¶
<<code>> ¶
mv -vi /etc/my.cnf.rpmsave /etc/my.cnf ¶
<</code>> ¶
¶
== MariaDB is a binary drop in replacement for MySQL ¶
¶
For all practical purposes, MariaDB is a binary drop in replacement of the same ¶
MySQL version (for example MySQL 5.1 -> MariaDB 5.1, MariaDB 5.2 & MariaDB 5.3 ¶
are compatible. MySQL 5.5 will be compatible with MariaDB 5.5). What this ¶
means is that: ¶
¶
* Data and table definition files (.frm) files are binary compatible. ¶
* All client APIs, protocols and structs are identical. ¶
* All filenames, binaries, paths, ports, sockets, and etc... should be the ¶
same. ¶
* All MySQL connectors (PHP, Perl, Python, Java, .NET, MyODBC, Ruby, MySQL C ¶
connector etc) work unchanged with MariaDB. ¶
** There are some [[installation-issues-with-php5|installation issues with PHP5]] ¶
that you should be aware of (a bug in how the old PHP5 client checks library ¶
compatibility). ¶
* The ##mysql-client## package also works with MariaDB server. ¶
¶
This means that for most cases, you can just uninstall MySQL and ¶
[[getting-installing-and-upgrading-mariadb|install MariaDB]] and you are good ¶
to go. (No need to convert any datafiles if you use same main version, like ¶
5.1). ¶
¶
We do monthly merges with the MySQL code base to ensure we keep up our ¶
compatibility and get any and all features and bug fixes Oracle adds. ¶
¶
We have also done a lot of work on the upgrade scripts to the point where it is now easier to ¶
[[upgrading-to-mariadb-from-mysql|upgrade from MySQL 5.0 to MariaDB 5.1]] than ¶
from MySQL 5.0 to MySQL 5.1. ¶
¶
That said, MariaDB has a lot of ¶
[[mariadb-versus-mysql-features|new options, extension, storage engines and bug fixes]] ¶
that are not in MySQL. You can find the feature set for the different MariaDB ¶
versions on the [[what-is-in-the-different-mariadb-releases|What is in the different MariaDB Releases]] page. ¶
¶
See also [[mariadb-versus-mysql-features | MariaDB versus MySQL - Features]]. ¶
¶
== Incompatibilities between MariaDB 5.1 and MySQL 5.1 ¶
¶
In some few cases MariaDB has to be incompatible to allow MariaDB to provide ¶
more and better information than MySQL. ¶
¶
Here is the list of all known user level incompatibilities you may see ¶
when using MariaDB 5.1 instead of MySQL 5.1. ¶
¶
* The installation package names starts with MariaDB instead of MySQL. ¶
* Timings may be different as MariaDB is in many cases faster than MySQL. ¶
* mysqld in MariaDB reads also the <<code>>[mariadb]<</code>> sections of your ¶
my.cnf files. ¶
* You can't use a binary only storage engine library with MariaDB if it's not ¶
compiled for exactly the same MariaDB version. (This is because the server ¶
internal structure THD is different between MySQL and MariaDB. This is common ¶
also between different MySQL versions). This should not be a problem as most ¶
people don't load new storage engines and MariaDB comes with more ¶
[[mariadb-storage-engines|more storage engines]] than MySQL. ¶
* ##CHECKSUM TABLE## may give different result as MariaDB doesn't ignore NULL's ¶
in the columns as MySQL 5.1 does (Future MySQL versions should calculate ¶
checksums the same way as MariaDB). You can get the 'old style' checksum in ¶
MariaDB by starting mysqld with the <<code>>--old<</code>> option. Note however that that ¶
the MyISAM and Aria storage engines in MariaDB are using the new checksum ¶
internally, so if you are using <<code>>--old<</code>>, the ##CHECKSUM## command will be ¶
slower as it needs to calculate the checksum row by row. ¶
* The slow query log has ¶
[[slow-query-log-extended-statistics|more information]] about the query, ¶
which may be a problem if you have a script which parses the slow query log. ¶
* MariaDB by default takes a bit more memory than MySQL because we have by ¶
default enabled the [[aria-formerly-known-as-maria|Aria storage engine]] for ¶
handling internal temporary tables. If you need MariaDB to take very little ¶
memory (at the expense of performance), you can set the value ¶
of ##aria_pagecache_buffer_size## to ##1M## (the default is ##128M##). ¶
* If you are using [[mysqld-startup-options|new command options]], ¶
[[mariadb-versus-mysql-features|new features of MariaDB]] or ¶
[[mariadb-storage-engines|new storage engines]], you can't move easily back ¶
and forth between MySQL and MariaDB anymore. ¶
¶
== Incompatibilities between MariaDB 5.2 and MySQL 5.1 ¶
¶
The list is the same as between MariaDB 5.1 and MySQL 5.1. ¶
¶
For all practical purposes, MariaDB 5.2 is a drop in replacement for MariaDB 5.1 and MySQL 5.1. ¶
¶
== Incompatibilities between MariaDB 5.3 and MySQL 5.1 and MariaDB 5.2 ¶
¶
* A few error messages related to wrong conversions are different as MariaDB ¶
provides more information in the message about what went wrong. ¶
* Error numbers for MariaDB specific errors has been moved to start from 1900 ¶
to not conflict with MySQL errors. ¶
* Microseconds now works in all contexts; MySQL did, in some contexts, lose the ¶
microsecond part from datetime and time. ¶
* The old <<code>>--maria-<</code>> startup options are removed. You should use ¶
the <<code>>--aria-<</code>> prefix instead. (MariaDB 5.2 supports both <<code>>--maria-<</code>> ¶
and <<code>>--aria-<</code>>) ¶
* ##[[show-processlist|SHOW PROCESSLIST]]## has an extra ##Progress## column ¶
which shows progress for some commands. You can disable it by ¶
starting ##mysqld## with the <<code>>--old<</code>> flag. ¶
* ##INFORMATION_SCHEMA.PROCESSLIST## has three new columns for progress ¶
reporting: ##STAGE##, ##MAX_STAGE##, and ##PROGRESS##. ¶
* [[comment-syntax|Long comments]] which start with <<code>>/*M!<</code>> ¶
or <<code>>/*M!#####<</code>> are executed. ¶
* If you use <<code>>max_user_connections=0<</code>> (which means any number ¶
of connections) when starting mysqld, you can't change the global variable ¶
anymore while mysqld remains running. This is because when mysqld is started ¶
with <<code>>max_user_connections=0<</code>> it does not allocate counting ¶
structures (which also involve a mutex for each connection). This would lead ¶
to wrong counters if you later changed the variable. If you want to be able ¶
to change this variable at runtime, set it to a high value at startup. ¶
* You can set <<code>>max_user_connections<</code>> (both the global variable ¶
and the ##GRANT## option) to ##-1## to stop users from connecting to the ¶
server. The global <<code>>max_user_connections<</code>> variable does not ¶
affect users with the <<code>>SUPER<</code>> privilege. ¶
* The [[ignore|IGNORE]] directive does not ignore all errors (like fatal errors), only things that are safe to ignore. ¶
¶
== Old, unsupported configuration options ¶
¶
If you are using any of the following options in your ##/etc/my.cnf## or other ¶
##my.cnf## file you should remove them. This is also true for MySQL 5.1 or ¶
newer: ¶
¶
* ##skip-bdb## ¶
¶
== Replacing a MySQL RPM == ¶
¶
If you uninstalled a MySQL RPM to install MariaDB, note that the MySQL RPM on ¶
uninstall renames ##/etc/my.cnf## to ##/etc/my.cnf.rpmsave##. ¶
¶
After installing MariaDB you should do the following to restore your old ¶
configuration options: ¶
¶
<<code>> ¶
mv -vi /etc/my.cnf.rpmsave /etc/my.cnf ¶
<</code>> ¶
¶
