Databases Reference
In-Depth Information
Percona Server has three primary goals:
Transparency
Added instrumentation permits users to inspect the server internals and behavior
more closely. This includes features such as counters in
SHOW STATUS
, tables in the
INFORMATION_SCHEMA
, and especially added verbosity in the slow query log.
Performance
Percona Server includes many improvements to performance and scalability. Raw
performance is important, but Percona Server also enhances predictability and the
stability of performance. Most of the focus is on InnoDB.
Operational flexibility
Percona Server contains many features that remove limitations. Although some of
the limitations seem small, they can make it hard for operations staff and system
administrators to run MySQL as a reliable and stable component of their infra-
structure.
Percona Server is a backwards-compatible drop-in replacement for MySQL, with min-
imal changes that do not alter SQL syntax, the client/server protocol, or file formats
on disk.
1
Anything that runs on MySQL will run without modification on Percona
Server. Switching to Percona Server requires only shutting down MySQL and starting
Percona Server, with no need to export and reimport data. Switching back is similarly
painless, and this is actually very important: many problems have been solved by
switching temporarily, using the improved instrumentation to diagnose the problem,
and then reverting to standard MySQL.
We choose enhancements that deviate from standard MySQL only where needed and
that provide significant benefit. We believe that most users are best served by sticking
to the official version of MySQL as distributed by Oracle, and strive to remain as close
to this as possible.
Percona Server includes the Percona XtraDB storage engine, Percona's enhanced ver-
sion of InnoDB. This is also a backward-compatible replacement. For example, if you
create a table with the InnoDB storage engine, Percona Server recognizes it automati-
cally and uses Percona XtraDB instead. Percona XtraDB is also included in MariaDB.
Some of the enhancements in Percona Server have been included into Oracle's version
of MySQL, and many others have been reimplemented in slightly different ways. As a
result, Percona Server has become a sort of early-access preview to features that some-
times appear later in standard MySQL. Many of the enhancements in Percona Server
5.1 and 5.5 are probably going to be reimplemented in MySQL 5.6.
1. Historically, there have been a few changes to file formats, but these are disabled by default and can be
enabled if desired.
