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1 General Information about MySQLThis is the MySQL reference manual; it documents MySQL version 3.22.29. MySQL is a very fast, multi-threaded, multi-user and robust SQL (Structured Query Language) database server. For Unix and OS/2 platforms, MySQL is basically free; for Microsoft platforms you must get a MySQL license after a trial time of 30 days. See section 3 MySQL licensing and support. The MySQL home page provides the latest information about MySQL. For a discussion of MySQL's capabilities, see section 1.5 The main features of MySQL. For installation instructions, see section 4 Installing MySQL. For tips on porting MySQL to new machines or operating systems, see section G Comments on porting to other systems. For information about upgrading from a 3.21 release, see section 4.16.2 Upgrading from a 3.21 version to 3.22. For a tutorial introduction to MySQL, see section 8 MySQL Tutorial. For examples of SQL and benchmarking information, see the benchmarking directory ('sql-bench' in the distribution). For a history of new features and bug fixes, see section D MySQL change history. For a list of currently known bugs and misfeatures, see section E Known errors and design deficiencies in MySQL. For future plans, see section F List of things we want to add to MySQL in the future (The TODO). For a list of all the contributors to this project, see section C Contributors to MySQL. IMPORTANT: Send bug (error) reports, questions and comments to the mailing list at
For source distributions, the If you have any suggestions concerning additions or corrections to this manual, please send them to the manual team at (docs@mysql.com). 1.1 What is MySQL?
MySQL is a true multi-user, multi-threaded SQL database
server. SQL (Structured Query Language) is the most popular and
standardized database language in the world. MySQL is a
client/server implementation that consists of a server daemon
SQL is a standardized language that makes it easy to store, update and access information. For example, you can use SQL to retrieve product information and store customer information for a web site. MySQL is also fast and flexible enough to allow you to store logs and pictures in it. The main goals of MySQL are speed, robustness and ease of use. MySQL was originally developed because we needed a SQL server that could handle very large databases an order of magnitude faster than what any database vendor could offer to us on inexpensive hardware. We have now been using MySQL since 1996 in an environment with more than 40 databases containing 10,000 tables, of which more than 500 have more than 7 million rows. This is about 100 gigabytes of mission-critical data. The base upon which MySQL is built is a set of routines that have been used in a highly demanding production environment for many years. Although MySQL is still under development, it already offers a rich and highly useful function set. The official way to pronounce MySQL is "My Ess Que Ell" (Not MY-SEQUEL). 1.2 About this manualThis manual is currently available in Texinfo, plain text, Info, HTML, PostScript and PDF versions. Because of their size, PostScript and PDF versions are not included with the main MySQL distribution, but are available for separate download at http://www.mysql.com.
The primary document is the Texinfo file. The HTML version is produced
automatically with a modified version of This manual is written and maintained by David Axmark, Michael (Monty) Widenius, Paul DuBois and Kim Aldale. For other contributors, see section C Contributors to MySQL. 1.2.1 Conventions used in this manualThis manual uses certain typographical conventions:
When commands are shown that are meant to be executed by a particular
program, the program is indicated by the prompt shown with the command. For
example, shell> type a shell command here mysql> type a mysql command here
Shell commands are shown using Bourne shell syntax. If you are using a
shell> VARNAME=value some_command
For shell> setenv VARNAME value shell> some_command
Database, table and column names often must be substituted into commands. To
indicate that such substitution is necessary, this manual uses
mysql> SELECT col_name FROM db_name.tbl_name; This means that if you were to enter a similar statement, you would supply your own database, table and column names, perhaps like this: mysql> SELECT author_name FROM biblio_db.author_list;
SQL statements may be written in uppercase or lowercase. When this manual
shows a SQL statement, uppercase is used for particular keywords if those
keywords are under discussion (to emphasize them) and lowercase is used for
the rest of the statement. So you might see the following in a discussion of
the mysql> SELECT count(*) FROM tbl_name;
On the other hand, in a discussion of the mysql> select COUNT(*) from tbl_name; If no particular emphasis is intended, all keywords are written uniformly in uppercase. In syntax descriptions, square brackets ('[' and ']') are used to indicate optional words or clauses: DROP TABLE [IF EXISTS] tbl_name When a syntax element consists of a number of alternatives, the alternatives are separated by vertical bars ('|'). When one member from a set of choices may be chosen, the alternatives are listed within square brackets. When one member from a set of choices must be chosen, the alternatives are listed within braces ('{' and '}'):
TRIM([[BOTH | LEADING | TRAILING] [remstr] FROM] str)
{DESCRIBE | DESC} tbl_name {col_name | wild}
1.3 History of MySQL
We once started off with the intention of using The derivation of the name MySQL is not perfectly clear. Our base directory and a large number of our libraries and tools have had the prefix "my" for well over 10 years. However, Monty's daughter (some years younger) is also named My. So which of the two gave its name to MySQL is still a mystery, even for us. 1.4 Books about MySQLWhile this manual is still the right place for up to date techical information, its primary goal is to contain everything there is to know about MySQL. And it is sometimes nice to have a bound book to read in bed or while you travel. Here are a list of books about MySQL (in English).
Foreword by Michael "Monty" Widenius, MySQL Moderator In MySQL, Paul DuBois provides you with a comprehensive guide to one of the most popular relational database systems. Paul has contributed to the online documentation for MySQL, and is an active member of the MySQL community. The principal MySQL developer, Monty Widenius, and a network of his fellow developers reviewed the manuscript, providing Paul with the kind of insight no one else could supply. Instead of merely giving you a general overview of MySQL, Paul teaches you how to make the most of its capabilities. Through two sample database applications that run throughout the book, he gives you solutions to problems you're sure to face. He helps you integrate MySQL efficiently with third-party tools, such as PHP and Perl, enabling you to generate dynamic Web pages through database queries. He teaches you to write programs that access MySQL databases, and also provides a comprehensive set of references to column types, operators, functions, SQL syntax, MySQL programming, C API, Perl DBI, and PHP API. MySQL simply gives you the kind of information you won't find anywhere else. If you use MySQL, this book provides you with:
This book teaches you how to use MySQL and mSQL, two popular and robust database products that support key subsets of SQL on both Linux and UNIX systems. Anyone who knows basic C, Java, Perl, or Python can write a program to interact with a database, either as a stand-alone application or through a Web page. This book takes you through the whole process, from installation and configuration to programming interfaces and basic administration. Includes ample tutorial material. 1.5 The main features of MySQLThe following list describes some of the important characteristics of MySQL:
1.6 How stable is MySQL?This section addresses the questions, "how stable is MySQL?" and, "can I depend on MySQL in this project?" Here we will try to clarify some issues and to answer some of the more important questions that seem to concern many people. This section has been put together from information gathered from the mailing list (which is very active in reporting bugs). At TcX, MySQL has worked without any problems in our projects since mid-1996. When MySQL was released to a wider public, we noticed that there were some pieces of "untested code" that were quickly found by the new users who made queries in a manner different than our own. Each new release has had fewer portability problems than the previous one (even though each has had many new features), and we hope that it will be possible to label one of the next releases "stable". Each release of MySQL has been usable and there have been problems only when users start to use code from "the gray zones". Naturally, outside users can't know what the gray zones are; this section attempts to indicate those that are currently known. The descriptions deal with the 3.22.x version of MySQL. All known and reported bugs are fixed in the latest version, with the exception of the bugs listed in the bugs section, which are things that are "design"-related. See section E Known errors and design deficiencies in MySQL. MySQL is written in multiple layers and different independent modules. These modules are listed below with an indication of how well-tested each of them is:
TcX provides email support for paying customers, but the MySQL mailing list usually provides answers to common questions. Bugs are usually fixed right away with a patch; for serious bugs, there is almost always a new release. 1.7 Year 2000 complianceMySQL itself has no problems with Year 2000 (Y2K) compliance:
You may run into problems with applications that use MySQL in a
way that is not Y2K-safe. For example, many old applications store
or manipulate years using 2-digit values (which are ambiguous) rather than
4-digit values. This problem may be compounded by applications that use
values such as Unfortunately, these problems may be difficult to fix, since different applications may be written by different programmers, each of whom may use a different set of conventions and date-handling functions. Here is a simple demonstration illustrating that MySQL doesn't have any problems with dates until the year 2030!
mysql> DROP TABLE IF EXISTS y2k;
mysql> CREATE TABLE y2k (date date, date_time datetime, time_stamp timestamp);
mysql> INSERT INTO y2k VALUES ("1998-12-31","1998-12-31 23:59:59",19981231235959);
mysql> INSERT INTO y2k VALUES ("1999-01-01","1999-01-01 00:00:00",19990101000000);
mysql> INSERT INTO y2k VALUES ("1999-09-09","1999-09-09 23:59:59",19990909235959);
mysql> INSERT INTO y2k VALUES ("2000-01-01","2000-01-01 00:00:00",20000101000000);
mysql> INSERT INTO y2k VALUES ("2000-02-28","2000-02-28 00:00:00",20000228000000);
mysql> INSERT INTO y2k VALUES ("2000-02-29","2000-02-29 00:00:00",20000229000000);
mysql> INSERT INTO y2k VALUES ("2000-03-01","2000-03-01 00:00:00",20000301000000);
mysql> INSERT INTO y2k VALUES ("2000-12-31","2000-12-31 23:59:59",20001231235959);
mysql> INSERT INTO y2k VALUES ("2001-01-01","2001-01-01 00:00:00",20010101000000);
mysql> INSERT INTO y2k VALUES ("2004-12-31","2004-12-31 23:59:59",20041231235959);
mysql> INSERT INTO y2k VALUES ("2005-01-01","2005-01-01 00:00:00",20050101000000);
mysql> INSERT INTO y2k VALUES ("2030-01-01","2030-01-01 00:00:00",20300101000000);
mysql> INSERT INTO y2k VALUES ("2050-01-01","2050-01-01 00:00:00",20500101000000);
mysql> SELECT * FROM y2k;
+------------+---------------------+----------------+
| date | date_time | time_stamp |
+------------+---------------------+----------------+
| 1998-12-31 | 1998-12-31 23:59:59 | 19981231235959 |
| 1999-01-01 | 1999-01-01 00:00:00 | 19990101000000 |
| 1999-09-09 | 1999-09-09 23:59:59 | 19990909235959 |
| 2000-01-01 | 2000-01-01 00:00:00 | 20000101000000 |
| 2000-02-28 | 2000-02-28 00:00:00 | 20000228000000 |
| 2000-02-29 | 2000-02-29 00:00:00 | 20000229000000 |
| 2000-03-01 | 2000-03-01 00:00:00 | 20000301000000 |
| 2000-12-31 | 2000-12-31 23:59:59 | 20001231235959 |
| 2001-01-01 | 2001-01-01 00:00:00 | 20010101000000 |
| 2004-12-31 | 2004-12-31 23:59:59 | 20041231235959 |
| 2005-01-01 | 2005-01-01 00:00:00 | 20050101000000 |
| 2030-01-01 | 2030-01-01 00:00:00 | 20300101000000 |
| 2050-01-01 | 2050-01-01 00:00:00 | 00000000000000 |
+------------+---------------------+----------------+
13 rows in set (0.00 sec)
This shows that the
The Even though MySQL is Y2K-compliant, it is your responsibility to provide unambiguous input. See section 7.3.6.1 Y2K issues and date types for MySQL's rules for dealing with ambiguous date input data (data containing 2-digit year values). 1.8 General SQL information and tutorialsThis book has been recommended by a several people on the MySQL mailing list: Judith S. Bowman, Sandra L. Emerson and Marcy Darnovsky The Practical SQL Handbook: Using Structured Query Language Second Edition Addison-Wesley ISBN 0-201-62623-3 http://www.awl.com This book has also received some recommendations by MySQL users: Martin Gruber Understanding SQL ISBN 0-89588-644-8 Publisher Sybex 510 523 8233 Alameda, CA USA A SQL tutorial is available on the net at http://www.geocities.com/SiliconValley/Vista/2207/sql1.html SQL in 21 Tagen (online book in German language): http://www.mut.de/leseecke/buecher/sql/inhalt.htm 1.9 Useful MySQL-related links1.9.1 Tutorials
1.9.2 Porting MySQL / Using MySQL on different systems
1.9.3 Perl related links1.9.4 MySQL discussion forums1.9.5 Commercial applications that support MySQL
1.9.6 SQL Clients/Report writers
1.9.7 Web development tools that support MySQL
1.9.8 Databse design tools with MySQL support1.9.9 Web servers with MySQL tools1.9.10 Extensions for other programs
1.9.11 Using
|
| Number of licenses | Price per copy | Total |
| 1 | US $200 | US $200 |
| 10 pack | US $150 | US $1500 |
| 50 pack | US $120 | US $6000 |
For high volume (OEM) purchases, the following prices apply:
| Number of licenses | Price per copy | Minimum at one time | Minimum payment |
| 100-999 | US $40 | 100 | US $4000 |
| 1000-2499 | US $25 | 200 | US $5000 |
| 2500-4999 | US $20 | 400 | US $8000 |
For OEM purchases, you must act as the middle-man for eventual problems or extension requests from your users. We also require that OEM customers have at least an extended email support contract.
If you have a low-margin high-volume product, you can always talk to us about other terms (for example, a percent of the sale price). If you do, please be informative about your product, pricing, market and any other information that may be relevant.
After buying 1 MySQL license, you will get a personal copy of
the myisampack utility. You are not allowed to redistribute this
utility but you can distribute tables packed with it.
A full-price license is not a support agreement and includes very minimal support. This means that we try to answer any relevant question. If the answer is in the documentation, we will direct you to the appropriate section. If you have not purchased a license or support, we probably will not answer at all.
If you discover what we consider a real bug, we are likely to fix it in any case. But if you pay for support we will notify you about the fix status instead of just fixing it in a later release.
More comprehensive support is sold separately. Descriptions of what each level of support includes are given in section 3.6 Types of commercial support. Costs for the various types of commercial support are shown below. Support level prices are in EURO (European Union Euro). One EURO is about 1.17 USD.
| Type of support | Cost per year |
| Basic email support | EURO 170 |
| Extended email support | EURO 1000 |
| Login support | EURO 2000 |
| Extended login support | EURO 5000 |
You may upgrade from any lower level of support to a higher level of support for the difference between the prices of the two support levels.
3.5.1 Payment information
Currently we can take SWIFT payments, cheques or credit cards.
Payment should be made to:
Postgirot Bank AB 105 06 STOCKHOLM, SWEDEN TCX DataKonsult AB BOX 6434 11382 STOCKHOLM, SWEDEN SWIFT address: PGSI SESS Account number: 96 77 06 - 3
Specify: license and/or support and your name and email address.
In Europe and Japan you can use EuroGiro (that should be less expensive) to the same account.
If you want to pay by cheque, make it payable to "Monty Program KB" and mail it to the address below:
TCX DataKonsult AB BOX 6434, Torsgatan 21 11382 STOCKHOLM, SWEDEN
If you want to pay by credit card over the Internet, you can use TcX's secure license form.
You can also print a copy of the license form, fill it in and send it by fax to:
+46-8-729 69 05
If you want us to bill you, you can use the license form and write "bill us" in the comment field. You can also mail a message to with your company information and ask us to bill you.
3.5.2 Contact information
For commercial licensing, or if you have any questions about any of the information in this section, please contact the MySQL licensing team. The much preferred method is by E-Mail to these may take much longer (Fax +46-8-729 69 05).
David Axmark Detron HB Kungsgatan 65 B 753 21 UPPSALA SWEDEN Voice Phone +46-18-10 22 80 (Timezone GMT+1. Swedish and English spoken)
3.6 Types of commercial support
3.6.1 Basic email support
Basic email support is a very inexpensive support option and should be thought of more as a way to support our development of MySQL than as a real support option.
At this support level, the MySQL mailing lists are the preferred means of communication. Questions normally should be mailed to the primary mailing list (mysql@lists.mysql.com) or one of the other regular lists (for example, mysql-win32@lists.mysql.com for Windows-related MySQL questions), as someone else already may have experienced and solved the problem you have. See section 2.2 Asking questions or reporting bugs.
However, by purchasing basic email support, you also have access to the support address mysql-support@mysql.com, which is not available as part of the minimal support that you get by purchasing a MySQL license. This means that for especially critical questions, you can cross-post your message to mysql-support@mysql.com. (If the message contains sensitive data, you should post only to mysql-support@mysql.com.)
REMEMBER! to ALWAYS include your registration number and expiration date when you send a message to
Basic email support includes the following types of service:
- If your question is already answered in the manual, we will inform you of the correct section in which you can find the answer. If the answer is not in the manual, we will point you in the right direction to solve your problem.
- We guarantee a timely answer for your email messages. We can't guarantee that we can solve any problem, but at least you will receive an answer if we can contact you by email.
- We will help with unexpected problems when you install MySQL from a binary distribution on supported platforms. This level of support does not cover installing MySQL from a source distribution. "Supported" platforms are those for which MySQL is known to work. See section 4.2 Operating systems supported by MySQL.
- We will help you with bugs and missing features. Any bugs that are found are fixed for the next MySQL release. If the bug is critical for you, we will mail you a patch for it as soon the bug is fixed. Critical bugs always have the highest priority for us, to ensure that they are fixed as soon as possible.
- Your suggestions for the further development of MySQL will be taken into consideration. By taking email support you have already helped the further development of MySQL. If you want to have more input, upgrade to a higher level of support.
- If you want us to help optimize your system, you must upgrade to a higher level of support.
-
We include a binary version of the
myisampackpacking tool for creating fast compressed read-only databases. The current server includes support for reading such databases but not the packing tool used to create them.
3.6.2 Extended email support
Extended email support includes everything in basic email support with these additions:
- Your email will be dealt with before mail from basic email support users and non-registered users.
- Your suggestions for the further development of MySQL will receive strong consideration. Simple extensions that suit the basic goals of MySQL are implemented in a matter of days. By taking extended email support you have already helped the further development of MySQL.
-
Typical questions that are covered by extended email support are:
- We will answer and (within reason) solve questions that relate to possible bugs in MySQL. As soon as the bug is found and corrected, we will mail a patch for it.
- We will help with unexpected problems when you install MySQL from a source or binary distribution on supported platforms.
- We will answer questions about missing features and offer hints how to work around them.
-
We will provide hints on optimizing
mysqldfor your situation.
- You are allowed to influence the priority of items on the MySQL TODO. This will ensure that the features you really need will be implemented sooner than they might be otherwise.
3.6.3 Login support
Login support includes everything in extended email support with these additions:
- Your email will be dealt with even before mail from extended email support users.
- Your suggestions for the further development of MySQL will be taken into very high consideration. Realistic extensions that can be implemented in a couple of hours and that suit the basic goals of MySQL will be implemented as soon as possible.
- If you have a very specific problem, we can try to log in on your system to solve the problem "in place."
-
Like any database vendor, we can't guarantee that we can rescue any data from
crashed tables, but if the worst happens we will help you rescue as much as
possible. MySQL has proven itself very reliable, but anything is
possible due to circumstances beyond our control (for example, if your system
crashes or someone kills the server by executing a
kill -9command). - We will provide hints on optimizing your system and your queries.
- You are allowed to call a MySQL developer (in moderation) and discuss your MySQL-related problems.
3.6.4 Extended login support
Extended login support includes everything in login support with these additions:
- Your email has the highest possible priority.
- We will actively examine your system and help you optimize it and your queries. We may also optimize and/or extend MySQL to better suit your needs.
-
You may also request special extensions just for you. For example:
mysql> select MY_CALCULATION(col_name1,col_name2) from tbl_name;
- We will provide a binary distribution of all important MySQL releases for your system, as long as we can get an account on a similar system. In the worst case, we may require access to your system to be able to create a binary distribution.
- If you can provide accommodations and pay for traveler fares, you can even get a MySQL developer to visit you and offer you help with your troubles. Extended login support entitles you to one personal encounter per year, but we are as always very flexible towards our customers!
4 Installing MySQL
This chapter describes how to obtain and install MySQL:
- For a list of sites from which you can obtain MySQL, see section 4.1 How to get MySQL.
- To see which platforms are supported, see section 4.2 Operating systems supported by MySQL.
- Several versions of MySQL are available, in both binary and source distributions. To determine which version and type of distribution you should use, see section 4.4 How and when updates are released.
- Installation instructions for binary and source distributions are described in section 4.6 Installing a MySQL binary distribution, and section 4.7 Installing a MySQL source distribution. Each set of instructions includes a section on system-specific problems you may run into.
- For post-installation procedures, see section 4.15 Post-installation setup and testing. These procedures apply whether you install MySQL using a binary or source distribution.
4.1 How to get MySQL
Check the MySQL home page for information about the current version and for downloading instructions.
However, the Internet connection at TcX is not so fast; we would prefer that you do the actual downloading from one of the mirror sites listed below.
Please report bad or out of date mirrors to webmaster@mysql.com.
Europe:
-
Austria [Univ. of Technology/Vienna]
WWW
FTP
-
Bulgaria [Naturella]
FTP
-
Croatia [HULK]
WWW
FTP
-
Czech Republic [Masaryk University in Brno]
WWW
FTP
-
Czech Republic [www.sopik.cz]
WWW
-
Denmark [Borsen]
WWW
-
Denmark [SunSITE]
WWW
FTP
-
Estonia [OKinteractive]
WWW
-
France [minet]
WWW
-
Finland [EUnet]
WWW
-
Finland [clinet]
FTP
-
Germany [Bonn University, Bonn]
WWW
FTP
-
Germany [Wolfenbuettel]
WWW
FTP
-
Germany [Staufen]
WWW
-
Germany [Cable & Wireless]
FTP
-
Greece [NTUA, Athens]
WWW
FTP
-
Island [GM]
WWW
WWW
-
Italy [Teta Srl]
WWW
-
Ireland [Ireland On-Line/Dublin]
WWW
FTP
-
Poland [Sunsite]
WWW
FTP
-
Portugal [lerianet]
WWW
FTP
-
Russia [DirectNet]
WWW
-
Russia [IZHCOM]
WWW
FTP
-
Russia [Scientific Center/Chernogolovka]
FTP
-
Romania [Timisoara]
WWW
FTP
-
Romania [Bucharest]
WWW
FTP
-
Spain [MasterD]
WWW
-
Sweden [Sunet]
WWW
FTP
-
Switzerland [Sunsite]
WWW
FTP
-
UK [Omnipotent/UK]
WWW
FTP
-
UK [PLiG/UK]
WWW
FTP
-
UK [SunSITE]
WWW
FTP
-
Ukraine [PACO]
WWW
FTP
North America:
-
Canada [Tryc]
WWW
-
Canada [Cyberus]
WWW
FTP
-
USA [Hurricane Electric/San Jose]
WWW
-
USA [Circle Net/North Carolina]
WWW
-
USA [Gina net/Florida]
WWW
-
USA [pingzero/Los Angeles]
WWW
-
USA [Wisconsin University/Wisconsin]
WWW
FTP
-
USA [DIGEX]
FTP
South America:
Brazil [Matrix]
Chile [Vision]
Asia:
-
China [Freecode]
WWW
-
China [Netfirm]
WWW
-
Korea [KREONet]
WWW
-
Japan [Soft Agency]
WWW
-
Japan [Nagoya Syouka University]
WWW
FTP
-
Singapore [HJC]
WWW
FTP
-
Taiwan [HT]
WWW
Australia:
-
Australia [AARNet/Queensland]
WWW
FTP
-
Australia [Tas]
WWW
FTP
-
Australia [Blue Planet/Melbourne]
WWW
-
Australia [ITworks Consulting/Victoria]
WWW
Africa:
South-Africa [Mweb/]
4.2 Operating systems supported by MySQL
We use GNU Autoconf so it is possible to port MySQL to all modern systems with working Posix threads and a C++ compiler. (To compile only the client code, a C++ compiler is required but not threads.) We use and develop the software ourselves primarily on Sun Solaris (versions 2.5 & 2.6) and to a lesser extent on RedHat Linux 5.0.
MySQL has been reported to compile sucessfully on the following operating system/thread package combinations. Note that for many operating systems, the native thread support works only in the latest versions.
- AIX 4.x with native threads
- BSDI 2.x with the included MIT-pthreads package
- BSDI 3.0, 3.1 and 4.x with native threads
- DEC UNIX 4.x with native threads
- FreeBSD 2.x with the included MIT-pthreads package
- FreeBSD 3.x with native threads
- HP-UX 10.20 with the included MIT-pthreads package
- HP-UX 11.x with the native threads.
-
Linux 2.0+ with LinuxThreads 0.7.1 or
glibc2.0.7 - MacOS X Server
- NetBSD 1.3/1.4 Intel and NetBSD 1.3 Alpha (Requires GNU make)
- OpenBSD 2.x with the included MIT-pthreads package
- OS/2 Warp 3, FixPack 29 and OS/2 Warp 4, FixPack 4
- SGI Irix 6.x with native threads
- Solaris 2.5, 2.6 and 2.7 with native threads on SPARC and x86
- SunOS 4.x with the included MIT-pthreads package
- SCO OpenServer with a recent port of the FSU Pthreads package
- SCO UnixWare 7.0.1
- Tru64 Unix
- Win95, Win98 and NT (the newest version is currently available only for users with a MySQL license or MySQL email support). For those who wish to test before they buy, we have released MySQL 3.21.29 (an older version) as shareware.
4.3 Which MySQL version to use
The first decision to make is whether you want to use the latest development release or the last stable release:
-
Normally, if you are beginning to use MySQL for the first time or
trying to port it to some system for which there is no binary distribution,
we recommend going with the development release (currently 3.22.x). This is
because there are usually no really serious bugs in the development release,
and you can easily test it on your machine with the
crash-meand benchmark tests. See section 10.8 Using your own benchmarks. - Otherwise, if you are running an old system and want to upgrade, but don't want to take chances with 3.22, you should upgrade to 3.21.33. We have tried to fix only fatal bugs and make small, relatively safe changes to that version.
The second decision to make is whether you want to use a source distribution or a binary distribution:
- If you want to run MySQL on a platform for which a current binary distribution exists, use that. Generally, it will be easier to install than a source distribution.
- If you want to read (and/or modify) the C and C++ code that makes up MySQL, you should get a source distribution. The source code is always the ultimate manual. Source distributions also contain more tests and examples than binary distributions.
The MySQL naming scheme uses release numbers that consist of three
numbers and a suffix. For example, a release name like
mysql-3.21.17-beta is interpreted like this:
-
The first number (
3) describes the file format. All version 3 releases have the same file format. When a version 4 appears, every table will have to be converted to the new format (nice tools for this will be included, of course). -
The second number (
21) is the release level. Normally there are two to choose from. One is the release/stable branch (currently21) and the other is the development branch (currently22) . Normally both are stable, but the development version may have quirks, missing documentation on new features or may fail to compile on some systems. -
The third number (
17) is the version number within the release level. This is incremented for each new distribution. Usually you want the latest version for the release level you have choosen. -
The suffix (
beta) indicates the stability level of the release. The possible suffixes are:alphaindicates that the release contains some large section of new code that hasn't been 100% tested. Known bugs (usually there are none) should be documented in the News section. See section D MySQL change history. There are also new commands and extensions in most alpha releases.-
betameans that all new code has been tested. No major new features were added. There should be no known bugs. -
gammais a beta that has been around a while and seems to work fine. This is what many other companies call a release. - If there is no suffix, it means that the version has been run for a while at many different sites with no reports of bugs other than platform-specific bugs. This is what we call a stable release.
All versions of MySQL are run through our standard tests and benchmarks to ensure that they are relatively safe to use. Since the standard tests are extended over time to check for all previously found bugs, the test suite keeps getting better.
Note that all releases have been tested at least with:
- An internal test suite
- This is part of a production system for a customer. It has many tables with hundreds of megabytes of data.
- The MySQL benchmark suite
- This runs a range of common queries. It is also a test to see whether the latest batch of optimizations actually made the code faster. See section 10.8 Using your own benchmarks.
- The
crash-metest - This tries to determine what features the database supports and what its capabilities and limitations are. See section 10.8 Using your own benchmarks.
Another test is that we use the newest MySQL version in our internal production environment, on at least one machine. We have more than 100 gigabytes of data to work with.
4.4 How and when updates are released
MySQL is evolving quite rapidly here at TcX and we want to share this with other MySQL users. We try to make a release when we have very useful features that others seem to have a need for.
We also try to help out users who request features that are easy to implement. We also take note of what our licensed users want to have and we especially take note of what our extended email supported customers want and try to help them out.
No one has to download a new release. The News section will tell you if the new release has something you really want. See section D MySQL change history.
We use the following policy when updating MySQL:
- For each minor update, the last number in the version string is incremented. When there are major new features or minor incompatibilities with previous versions, the second number in the version string is incremented. When the file format changes, the first number is increased.
- Stable tested releases are meant to appear about 1-2 times a year, but if small bugs are found, a release with only bug-fixes will be released.
- Working releases are meant to appear about every 1-8 weeks.
- Binary distributions for some platforms will be made by us for major releases. Other people may make binary distributions for other systems but probably less frequently.
- We usually make patches available as soon as we have located and fixed small bugs.
- For non-critical but annoying bugs, we will make patches available if they are sent to us. Otherwise we will combine many of them into a larger patch.
- If there is, by any chance, a fatal bug in a release we will make a new release as soon as possible. We would like other companie