MySQL 5.1 is the current development release series.

MySQL 5.0 is the current stable (production-quality) release series. New releases are issued for bugfixes only; no new features are being added that could effect stability.

MySQL 4.1 is the previous stable (production-quality) release series. New releases are issued for critical bugfixes and security fixes. No significant new features are to be added to this series.

MySQL 4.0 and 3.23 are the old stable (production-quality) release series. These versions are now retired, so new releases are issued only to fix extremely critical bugs (primarily security issues).

The first number (5) is the major version and describes the file format. All MySQL 5 releases have the same file format.

The second number (0) is the release level. Taken together, the major version and release level constitute the release series number.

The third number (12) is the version number within the release series. This is incremented for each new release. Usually you want the latest version for the series you have chosen.

alpha indicates that the release is for preview purposes only. Known bugs should be documented in the News section (see Appendix E, MySQL Change History). Most alpha releases implement new commands and extensions. Active development that may involve major code changes can occur in an alpha release. However, we do conduct testing before issuing a release.

beta indicates that the release is appropriate for use with new development. Within beta releases, the features and compatibility should remain consistent. However, beta releases may contain numerous and major unaddressed bugs.

All APIs, externally visible structures, and columns for SQL statements will not change during future beta, release candidate, or production releases.

rc indicates a Release Candidate. Release candidates are believed to be stable, having passed all of MySQL's internal testing, and with all known fatal runtime bugs fixed. However, the release has not been in widespread use long enough to know for sure that all bugs have been identified. Only minor fixes are added. (A release candidate is what formerly was known as a gamma release.)

If there is no suffix, it indicates that the release is a General Availability (GA) or Production release. GA releases are stable, having successfully passed through all earlier release stages and are believed to be reliable, free of serious bugs, and suitable for use in production systems. Only critical bugfixes are applied to the release.

An internal test suite

The mysql-test directory contains an extensive set of test cases. We run these tests for every server binary. See Section 24.1.2, “MySQL Test Suite”, for more information about this test suite.

The MySQL benchmark suite

This suite runs a range of common queries. It is also a test to determine whether the latest batch of optimizations actually made the code faster. See Section 7.1.4, “The MySQL Benchmark Suite”.

The crash-me test

This test tries to determine what features the database supports and what its capabilities and limitations are. See Section 7.1.4, “The MySQL Benchmark Suite”.

Binary distributions generally are easier to install than source distributions.

To satisfy different user requirements, we provide several servers in binary distributions. mysqld is an optimized server that is a smaller, faster binary. mysqld-debug is compiled with debugging support.

Each of these servers is compiled from the same source distribution, though with different configuration options. All native MySQL clients can connect to servers from either MySQL version.

You want to install MySQL at some explicit location. The standard binary distributions are ready to run at any installation location, but you might require even more flexibility to place MySQL components where you want.

You want to configure mysqld to ensure that features are available that might not be included in the standard binary distributions. Here is a list of the most common extra options that you may want to use to ensure feature availability:

You want to configure mysqld without some features that are included in the standard binary distributions. For example, distributions normally are compiled with support for all character sets. If you want a smaller MySQL server, you can recompile it with support for only the character sets you need.

You have a special compiler (such as pgcc) or want to use compiler options that are better optimized for your processor. Binary distributions are compiled with options that should work on a variety of processors from the same processor family.

You want to use the latest sources from one of the BitKeeper repositories to have access to all current bugfixes. For example, if you have found a bug and reported it to the MySQL development team, the bugfix is committed to the source repository and you can access it there. The bugfix does not appear in a release until a release actually is issued.

You want to read (or modify) the C and C++ code that makes up MySQL. For this purpose, you should get a source distribution, because the source code is always the ultimate manual.

Source distributions contain more tests and examples than binary distributions.

Enterprise Server releases are meant to appear every 18 months, supplemented by quarterly service packs and monthly rapid updates. Community Server releases are meant to appear 2–3 times per year.

Releases are issued within each series. Enterprise Server releases are numbered using even numbers (for example, 5.0.20). Community Server releases are numbered using odd numbers (for example, 5.0.21).

Binary distributions for some platforms are made by us for major releases. Other people may make binary distributions for other systems, but probably less frequently.

We make fixes available as soon as we have identified and corrected small or non-critical but annoying bugs. The fixes are available in source form immediately from our public BitKeeper repositories, and are included in the next release.

If by any chance a security vulnerability or critical bug is found in a release, our policy is to fix it in a new release as soon as possible. (We would like other companies to do this, too!)

We monitor bugs from our customer support list, the bugs database at http://bugs.mysql.com/, and the MySQL external mailing lists.

All reported bugs for live versions are entered into the bugs database.

When we fix a bug, we always try to make a test case for it and include it into our test system to ensure that the bug can never recur without being detected. (About 90% of all fixed bugs have test cases.)

We create test cases for each new feature that we add to MySQL.

Before we start to build a new MySQL release, we ensure that all reported repeatable bugs for that MySQL version (3.23.x, 4.0.x, 4.1.x, 5.0.x, 5.1.x, and so on) are fixed. If something is impossible to fix due to some internal design decision in MySQL, we document this in the manual. See Section B.1.8, “Known Issues in MySQL”.

We do a build on all platforms for which we support binaries and run our test suite and benchmark suite on all of them.

We do not publish a binary for a platform for which the test or benchmark suite fails. If the problem is due to a general error in the source, we fix it and do the build plus tests on all systems again from scratch.

The build and test process takes a week. If we receive a report regarding a fatal bug during this process (for example, one that causes a core dump), we fix the problem and restart the build process.

After publishing the binaries on http://dev.mysql.com/, we send out an announcement message to the mysql and announce mailing lists. See Section 1.7.1, “MySQL Mailing Lists”. The announcement message contains a list of all changes to the release and any known problems with the release. The Known Problems section in the release notes has been needed for only a handful of releases.

To quickly give our users access to the latest MySQL features, we try to produce a new MySQL release every 4-8 weeks. Source code snapshots are built daily and are available at http://downloads.mysql.com/snapshots.php.

If, despite our best efforts, we receive any bug reports after a release is issued that a critical problem exists for the build on a specific platform, we fix it at once and build a new 'a' release for that platform. Thanks to our large user base, problems are found and resolved very quickly.

Our track record for making stable releases is quite good. In the last 150 releases, we had to do a new build for fewer than 10 of them. In three of these cases, the bug was a faulty glibc library on one of our build machines that took us a long time to track down.

Linux 2.4.xx x86 with gcc 2.95.3:

CFLAGS="-O2 -mcpu=pentiumpro" CXX=gcc CXXFLAGS="-O2 -mcpu=pentiumpro
-felide-constructors" ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --enable-assembler --disable-shared
--with-client-ldflags=-all-static --with-mysqld-ldflags=-all-static

Linux 2.4.x x86 with icc (Intel C++ Compiler 8.1 or later releases):

CC=icc CXX=icpc CFLAGS="-O3 -unroll2 -ip -mp -no-gcc -restrict"
CXXFLAGS="-O3 -unroll2 -ip -mp -no-gcc -restrict" ./configure
--prefix=/usr/local/mysql --localstatedir=/usr/local/mysql/data
--libexecdir=/usr/local/mysql/bin --with-extra-charsets=complex
--enable-thread-safe-client --enable-local-infile --enable-assembler
--disable-shared --with-client-ldflags=-all-static
--with-mysqld-ldflags=-all-static --with-embedded-server --with-innodb

Note that versions 8.1 and newer of the Intel compiler have separate drivers for 'pure' C (icc) and C++ (icpc); if you use icc version 8.0 or older for building MySQL, you will need to set CXX=icc.

Linux 2.4.xx Intel Itanium 2 with ecc (Intel C++ Itanium Compiler 7.0):

CC=ecc CFLAGS="-O2 -tpp2 -ip -nolib_inline" CXX=ecc CXXFLAGS="-O2
-tpp2 -ip -nolib_inline" ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile

Linux 2.4.xx Intel Itanium with ecc (Intel C++ Itanium Compiler 7.0):

CC=ecc CFLAGS=-tpp1 CXX=ecc CXXFLAGS=-tpp1 ./configure
--prefix=/usr/local/mysql --with-extra-charsets=complex
--enable-thread-safe-client --enable-local-infile

Linux 2.4.xx alpha with ccc (Compaq C V6.2-505 / Compaq C++ V6.3-006):

CC=ccc CFLAGS="-fast -arch generic" CXX=cxx CXXFLAGS="-fast -arch
generic -noexceptions -nortti" ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --with-mysqld-ldflags=-non_shared
--with-client-ldflags=-non_shared --disable-shared

Linux 2.x.xx ppc with gcc 2.95.4:

CC=gcc CFLAGS="-O3 -fno-omit-frame-pointer" CXX=gcc CXXFLAGS="-O3
-fno-omit-frame-pointer -felide-constructors -fno-exceptions
-fno-rtti" ./configure --prefix=/usr/local/mysql
--localstatedir=/usr/local/mysql/data --libexecdir=/usr/local/mysql/bin
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --disable-shared --with-embedded-server
--with-innodb

Linux 2.4.xx s390 with gcc 2.95.3:

CFLAGS="-O2" CXX=gcc CXXFLAGS="-O2 -felide-constructors" ./configure
--prefix=/usr/local/mysql --with-extra-charsets=complex
--enable-thread-safe-client --enable-local-infile --disable-shared
--with-client-ldflags=-all-static --with-mysqld-ldflags=-all-static

Linux 2.4.xx x86_64 (AMD64) with gcc 3.2.1:

CXX=gcc ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --disable-shared

Sun Solaris 8 x86 with gcc 3.2.3:

CC=gcc CFLAGS="-O3 -fno-omit-frame-pointer" CXX=gcc CXXFLAGS="-O3
-fno-omit-frame-pointer -felide-constructors -fno-exceptions
-fno-rtti" ./configure --prefix=/usr/local/mysql
--localstatedir=/usr/local/mysql/data --libexecdir=/usr/local/mysql/bin
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --disable-shared --with-innodb

Sun Solaris 8 SPARC with gcc 3.2:

CC=gcc CFLAGS="-O3 -fno-omit-frame-pointer" CXX=gcc CXXFLAGS="-O3
-fno-omit-frame-pointer -felide-constructors -fno-exceptions
-fno-rtti" ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --enable-assembler --with-named-z-libs=no
--with-named-curses-libs=-lcurses --disable-shared

Sun Solaris 8 SPARC 64-bit with gcc 3.2:

CC=gcc CFLAGS="-O3 -m64 -fno-omit-frame-pointer" CXX=gcc CXXFLAGS="-O3
-m64 -fno-omit-frame-pointer -felide-constructors -fno-exceptions
-fno-rtti" ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --with-named-z-libs=no
--with-named-curses-libs=-lcurses --disable-shared

Sun Solaris 9 SPARC with gcc 2.95.3:

CC=gcc CFLAGS="-O3 -fno-omit-frame-pointer" CXX=gcc CXXFLAGS="-O3
-fno-omit-frame-pointer -felide-constructors -fno-exceptions
-fno-rtti" ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --enable-assembler --with-named-curses-libs=-lcurses
--disable-shared

Sun Solaris 9 SPARC with cc-5.0 (Sun Forte 5.0):

CC=cc-5.0 CXX=CC ASFLAGS="-xarch=v9" CFLAGS="-Xa -xstrconst -mt
-D_FORTEC_ -xarch=v9" CXXFLAGS="-noex -mt -D_FORTEC_ -xarch=v9"
./configure --prefix=/usr/local/mysql --with-extra-charsets=complex
--enable-thread-safe-client --enable-local-infile --enable-assembler
--with-named-z-libs=no --enable-thread-safe-client --disable-shared

IBM AIX 4.3.2 ppc with gcc 3.2.3:

CFLAGS="-O2 -mcpu=powerpc -Wa,-many " CXX=gcc CXXFLAGS="-O2
-mcpu=powerpc -Wa,-many -felide-constructors -fno-exceptions
-fno-rtti" ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --with-named-z-libs=no --disable-shared

IBM AIX 4.3.3 ppc with xlC_r (IBM Visual Age C/C++ 6.0):

CC=xlc_r CFLAGS="-ma -O2 -qstrict -qoptimize=2 -qmaxmem=8192"
CXX=xlC_r CXXFLAGS ="-ma -O2 -qstrict -qoptimize=2 -qmaxmem=8192"
./configure --prefix=/usr/local/mysql --localstatedir=/usr/local/mysql/data
--libexecdir=/usr/local/mysql/bin --with-extra-charsets=complex
--enable-thread-safe-client --enable-local-infile --with-named-z-libs=no
--disable-shared --with-innodb

IBM AIX 5.1.0 ppc with gcc 3.3:

CFLAGS="-O2 -mcpu=powerpc -Wa,-many" CXX=gcc CXXFLAGS="-O2 -mcpu=powerpc
-Wa,-many -felide-constructors -fno-exceptions -fno-rtti" ./configure
--prefix=/usr/local/mysql --with-extra-charsets=complex
--enable-thread-safe-client --enable-local-infile --with-named-z-libs=no
--disable-shared

IBM AIX 5.2.0 ppc with xlC_r (IBM Visual Age C/C++ 6.0):

CC=xlc_r CFLAGS="-ma -O2 -qstrict -qoptimize=2 -qmaxmem=8192"
CXX=xlC_r CXXFLAGS="-ma -O2 -qstrict -qoptimize=2 -qmaxmem=8192"
./configure --prefix=/usr/local/mysql --localstatedir=/usr/local/mysql/data
--libexecdir=/usr/local/mysql/bin --with-extra-charsets=complex
--enable-thread-safe-client --enable-local-infile --with-named-z-libs=no
--disable-shared --with-embedded-server --with-innodb

HP-UX 10.20 pa-risc1.1 with gcc 3.1:

CFLAGS="-DHPUX -I/opt/dce/include -O3 -fPIC" CXX=gcc CXXFLAGS="-DHPUX
-I/opt/dce /include -felide-constructors -fno-exceptions -fno-rtti
-O3 -fPIC" ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --with-pthread --with-named-thread-libs=-ldce
--with-lib-ccflags=-fPIC --disable-shared

HP-UX 11.00 pa-risc with aCC (HP ANSI C++ B3910B A.03.50):

CC=cc CXX=aCC CFLAGS=+DAportable CXXFLAGS=+DAportable ./configure
--prefix=/usr/local/mysql --localstatedir=/usr/local/mysql/data
--libexecdir=/usr/local/mysql/bin --with-extra-charsets=complex
--enable-thread-safe-client --enable-local-infile --disable-shared
--with-embedded-server --with-innodb

HP-UX 11.11 pa-risc2.0 64bit with aCC (HP ANSI C++ B3910B A.03.33):

CC=cc CXX=aCC CFLAGS=+DD64 CXXFLAGS=+DD64 ./configure
--prefix=/usr/local/mysql --with-extra-charsets=complex
--enable-thread-safe-client --enable-local-infile --disable-shared

HP-UX 11.11 pa-risc2.0 32bit with aCC (HP ANSI C++ B3910B A.03.33):

CC=cc CXX=aCC CFLAGS="+DAportable" CXXFLAGS="+DAportable" ./configure
--prefix=/usr/local/mysql --localstatedir=/usr/local/mysql/data
--libexecdir=/usr/local/mysql/bin --with-extra-charsets=complex
--enable-thread-safe-client --enable-local-infile --disable-shared
--with-innodb

HP-UX 11.22 ia64 64bit with aCC (HP aC++/ANSI C B3910B A.05.50):

CC=cc CXX=aCC CFLAGS="+DD64 +DSitanium2" CXXFLAGS="+DD64 +DSitanium2"
./configure --prefix=/usr/local/mysql --localstatedir=/usr/local/mysql/data
--libexecdir=/usr/local/mysql/bin --with-extra-charsets=complex
--enable-thread-safe-client --enable-local-infile --disable-shared
--with-embedded-server --with-innodb

Apple Mac OS X 10.2 powerpc with gcc 3.1:

CC=gcc CFLAGS="-O3 -fno-omit-frame-pointer" CXX=gcc CXXFLAGS="-O3
-fno-omit-frame-pointer -felide-constructors -fno-exceptions
-fno-rtti" ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --disable-shared

FreeBSD 4.7 i386 with gcc 2.95.4:

CFLAGS=-DHAVE_BROKEN_REALPATH ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --enable-assembler --with-named-z-libs=not-used
--disable-shared

FreeBSD 4.7 i386 using LinuxThreads with gcc 2.95.4:

CFLAGS="-DHAVE_BROKEN_REALPATH -D__USE_UNIX98 -D_REENTRANT
-D_THREAD_SAFE -I/usr/local/include/pthread/linuxthreads"
CXXFLAGS="-DHAVE_BROKEN_REALPATH -D__USE_UNIX98 -D_REENTRANT
-D_THREAD_SAFE -I/usr/local/include/pthread/linuxthreads" ./configure
--prefix=/usr/local/mysql --localstatedir=/usr/local/mysql/data
--libexecdir=/usr/local/mysql/bin --enable-thread-safe-client
--enable-local-infile --enable-assembler
--with-named-thread-libs="-DHAVE_GLIBC2_STYLE_GETHOSTBYNAME_R
-D_THREAD_SAFE -I /usr/local/include/pthread/linuxthreads
-L/usr/local/lib -llthread -llgcc_r" --disable-shared
--with-embedded-server --with-innodb

QNX Neutrino 6.2.1 i386 with gcc 2.95.3qnx-nto 20010315:

CC=gcc CFLAGS="-O3 -fno-omit-frame-pointer" CXX=gcc CXXFLAGS="-O3
-fno-omit-frame-pointer -felide-constructors -fno-exceptions
-fno-rtti" ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --disable-shared

SCO Unix 3.2v5.0.7 i386 with gcc 2.95.3:

CFLAGS="-O3 -mpentium" LDFLAGS=-static CXX=gcc CXXFLAGS="-O3 -mpentium
-felide-constructors" ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --with-named-z-libs=no --enable-thread-safe-client
--disable-shared

SCO UnixWare 7.1.4 i386 with CC 3.2:

CC=cc CFLAGS="-O" CXX=CC ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --with-named-z-libs=no --enable-thread-safe-client
--disable-shared --with-readline

SCO OpenServer 6.0.0 i386 with CC 3.2:

CC=cc CFLAGS="-O" CXX=CC ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --with-named-z-libs=no --enable-thread-safe-client
--disable-shared --with-readline

Compaq Tru64 OSF/1 V5.1 732 alpha with cc/cxx (Compaq C V6.3-029i / DIGITAL C++ V6.1-027):

CC="cc -pthread" CFLAGS="-O4 -ansi_alias -ansi_args -fast -inline
speed -speculate all" CXX="cxx -pthread" CXXFLAGS="-O4 -ansi_alias
-fast -inline speed -speculate all -noexceptions -nortti" ./configure
--prefix=/usr/local/mysql --with-extra-charsets=complex
--enable-thread-safe-client --enable-local-infile
--with-named-thread-libs="-lpthread -lmach -lexc -lc" --disable-shared
--with-mysqld-ldflags=-all-static

SGI Irix 6.5 IP32 with gcc 3.0.1:

CC=gcc CFLAGS="-O3 -fno-omit-frame-pointer" CXXFLAGS="-O3
-fno-omit-frame-pointer -felide-constructors -fno-exceptions
-fno-rtti" ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --disable-shared

FreeBSD/sparc64 5.0 with gcc 3.2.1:

CFLAGS=-DHAVE_BROKEN_REALPATH ./configure --prefix=/usr/local/mysql
--localstatedir=/usr/local/mysql/data --libexecdir=/usr/local/mysql/bin
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --disable-shared --with-innodb

Linux 2.2.xx SPARC with egcs 1.1.2:

CC=gcc CFLAGS="-O3 -fno-omit-frame-pointer" CXX=gcc CXXFLAGS="-O3
-fno-omit-frame-pointer -felide-constructors -fno-exceptions
-fno-rtti" ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex --enable-thread-safe-client
--enable-local-infile --enable-assembler --disable-shared

Linux 2.2.x with x686 with gcc 2.95.2:

CFLAGS="-O3 -mpentiumpro" CXX=gcc CXXFLAGS="-O3 -mpentiumpro
-felide-constructors -fno-exceptions -fno-rtti" ./configure
--prefix=/usr/local/mysql --enable-assembler
--with-mysqld-ldflags=-all-static --disable-shared
--with-extra-charsets=complex

SunOS 4.1.4 2 sun4c with gcc 2.7.2.1:

CC=gcc CXX=gcc CXXFLAGS="-O3 -felide-constructors" ./configure
--prefix=/usr/local/mysql --disable-shared --with-extra-charsets=complex
--enable-assembler

SunOS 5.5.1 (and above) sun4u with egcs 1.0.3a or 2.90.27 or gcc 2.95.2 and newer:

CC=gcc CFLAGS="-O3" CXX=gcc CXXFLAGS="-O3 -felide-constructors
-fno-exceptions -fno-rtti" ./configure --prefix=/usr/local/mysql
--with-low-memory --with-extra-charsets=complex --enable-assembler

SunOS 5.6 i86pc with gcc 2.8.1:

CC=gcc CXX=gcc CXXFLAGS=-O3 ./configure --prefix=/usr/local/mysql
--with-low-memory --with-extra-charsets=complex

BSDI BSD/OS 3.1 i386 with gcc 2.7.2.1:

CC=gcc CXX=gcc CXXFLAGS=-O ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex

BSDI BSD/OS 2.1 i386 with gcc 2.7.2:

CC=gcc CXX=gcc CXXFLAGS=-O3 ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex

AIX 4.2 with gcc 2.7.2.2:

CC=gcc CXX=gcc CXXFLAGS=-O3 ./configure --prefix=/usr/local/mysql
--with-extra-charsets=complex

The Essentials Package: This package has a filename similar to mysql-essential-5.0.42-win32.msi and contains the minimum set of files needed to install MySQL on Windows, including the Configuration Wizard. This package does not include optional components such as the embedded server and benchmark suite.

The Complete Package: This package has a filename similar to mysql-5.0.42-win32.zip and contains all files needed for a complete Windows installation, including the Configuration Wizard. This package includes optional components such as the embedded server and benchmark suite.

The Noinstall Archive: This package has a filename similar to mysql-noinstall-5.0.42-win32.zip and contains all the files found in the Complete install package, with the exception of the Configuration Wizard. This package does not include an automated installer, and must be manually installed and configured.

The installation or data directory locations are different from the default locations (C:\Program Files\MySQL\MySQL Server 5.0 and C:\Program Files\MySQL\MySQL Server 5.0\data).

You need to tune the server settings.

Named pipes are enabled only if you start the server with the --enable-named-pipe option. It is necessary to use this option explicitly because some users have experienced problems with shutting down the MySQL server when named pipes were used.

Named-pipe connections are allowed only by the mysqld-nt and mysqld-debug servers.

On the Windows desktop, right-click on the My Computer icon, and select Properties

Next select the Advanced tab from the System Properties menu that appears, and click the Environment Variables button.

Under System Variables, select Path, and then click the Edit button. The Edit System Variable dialogue should appear.

Place your cursor at the end of the text appearing in the space marked Variable Value. (Use the End key to ensure that your cursor is positioned at the very end of the text in this space.) Then enter the complete pathname of your MySQL bin directory (for example, C:\Program Files\MySQL\MySQL Server 5.0\bin), Note that there should be a semicolon separating this path from any values present in this field. Dismiss this dialogue, and each dialogue in turn, by clicking OK until all of the dialogues that were opened have been dismissed. You should now be able to invoke any MySQL executable program by typing its name at the DOS prompt from any directory on the system, without having to supply the path. This includes the servers, the mysql client, and all MySQL command-line utilities such as mysqladmin and mysqldump.

You should not add the MySQL bin directory to your Windows PATH if you are running multiple MySQL servers on the same machine.

You can specify a service name immediately following the --install option. The default service name is MySQL.

If a service name is given, it can be followed by a single option. By convention, this should be --defaults-file=file_name to specify the name of an option file from which the server should read options when it starts.

It is possible to use a single option other than --defaults-file, but this is discouraged. --defaults-file is more flexible because it enables you to specify multiple startup options for the server by placing them in the named option file. Also, in MySQL 5.0, use of an option different from --defaults-file is not supported until 5.0.3.

As of MySQL 5.0.1, you can also specify a --local-service option following the service name. This causes the server to run using the LocalService Windows account that has limited system privileges. This account is available only for Windows XP or newer. If both --defaults-file and --local-service are given following the service name, they can be in any order.

If the service-installation command specifies no service name or the default service name (MySQL) following the --install option, the server uses the a service name of MySQL and reads options from the [mysqld] group in the standard option files.

If the service-installation command specifies a service name other than MySQL following the --install option, the server uses that service name. It reads options from the group that has the same name as the service, and reads options from the standard option files.

The server also reads options from the [mysqld] group from the standard option files. This allows you to use the [mysqld] group for options that should be used by all MySQL services, and an option group with the same name as a service for use by the server installed with that service name.

If the service-installation command specifies a --defaults-file option after the service name, the server reads options only from the [mysqld] group of the named file and ignores the standard option files.

If the MySQL server cannot find the mysql privileges database or other critical files, you may see these messsages:

System error 1067 has occurred.
Fatal error: Can't open privilege tables: Table 'mysql.host' doesn't exist

These messages often occur when the MySQL base or data directories are installed in different locations than the default locations (C:\Program Files\MySQL\MySQL Server 5.0 and C:\Program Files\MySQL\MySQL Server 5.0\data, respectively).

This situation may occur when MySQL is upgraded and installed to a new location, but the configuration file is not updated to reflect the new location. In addition, there may be old and new configuration files that conflict. Be sure to delete or rename any old configuration files when upgrading MySQL.

If you have installed MySQL to a directory other than C:\Program Files\MySQL\MySQL Server 5.0, you need to ensure that the MySQL server is aware of this through the use of a configuration (my.ini) file. The my.ini file needs to be located in your Windows directory, typically C:\WINDOWS. You can determine its exact location from the value of the WINDIR environment variable by issuing the following command from the command prompt:

C:\> echo %WINDIR%

An option file can be created and modified with any text editor, such as Notepad. For example, if MySQL is installed in E:\mysql and the data directory is D:\MySQLdata, you can create the option file and set up a [mysqld] section to specify values for the basedir and datadir parameters:

[mysqld]
# set basedir to your installation path
basedir=E:/mysql
# set datadir to the location of your data directory
datadir=D:/MySQLdata

Note that Windows pathnames are specified in option files using (forward) slashes rather than backslashes. If you do use backslashes, you must double them:

[mysqld]
# set basedir to your installation path
basedir=C:\\Program Files\\MySQL\\MySQL Server 5.0
# set datadir to the location of your data directory
datadir=D:\\MySQLdata

MySQL Enterprise For expert advice on the start-up options appropriate to your circumstances, subscribe to the MySQL Network Monitoring and Advisory Service. For more information see, http://www.mysql.com/products/enterprise/advisors.html.

If you change the datadir value in your MySQL configuration file, you must move the contents of the existing MySQL data directory before restarting the MySQL server.

See Section 2.4.8.7, “Creating an Option File”.

If you reinstall or upgrade MySQL without first stopping and removing the existing MySQL service and install MySQL using the MySQL Configuration Wizard, you may see this error:

Error: Cannot create Windows service for MySql. Error: 0

This occurs when the Configuration Wizard tries to install the service and finds an existing service with the same name.

One solution to this problem is to choose a service name other than mysql when using the configuration wizard. This allows the new service to be installed correctly, but leaves the outdated service in place. Although this is harmless, it is best to remove old services that are no longer in use.

To permanently remove the old mysql service, execute the following command as a user with administrative privileges, on the command-line:

C:\> sc delete mysql
[SC] DeleteService SUCCESS

If the sc utility is not available for your version of Windows, download the delsrv utility from http://www.microsoft.com/windows2000/techinfo/reskit/tools/existing/delsrv-o.asp and use the delsrv mysql syntax.

Limited number of ports

Windows systems have about 4,000 ports available for client connections, and after a connection on a port closes, it takes two to four minutes before the port can be reused. In situations where clients connect to and disconnect from the server at a high rate, it is possible for all available ports to be used up before closed ports become available again. If this happens, the MySQL server appears to be unresponsive even though it is running. Note that ports may be used by other applications running on the machine as well, in which case the number of ports available to MySQL is lower.

For more information about this problem, see http://support.microsoft.com/default.aspx?scid=kb;en-us;196271.

Concurrent reads

MySQL depends on the pread() and pwrite() system calls to be able to mix INSERT and SELECT. Currently, we use mutexes to emulate pread() and pwrite(). We intend to replace the file level interface with a virtual interface in the future so that we can use the readfile()/writefile() interface to get more speed. The current implementation limits the number of open files that MySQL 5.0 can use to 2,048, which means that you cannot run as many concurrent threads on Windows as on Unix.

Blocking read

MySQL uses a blocking read for each connection. That has the following implications if named-pipe connections are enabled:

We plan to fix this problem in the future.

ALTER TABLE

While you are executing an ALTER TABLE statement, the table is locked from being used by other threads. This has to do with the fact that on Windows, you can't delete a file that is in use by another thread. In the future, we may find some way to work around this problem.

DROP TABLE

DROP TABLE on a table that is in use by a MERGE table does not work on Windows because the MERGE handler does the table mapping hidden from the upper layer of MySQL. Because Windows does not allow dropping files that are open, you first must flush all MERGE tables (with FLUSH TABLES) or drop the MERGE table before dropping the table.

DATA DIRECTORY and INDEX DIRECTORY

The DATA DIRECTORY and INDEX DIRECTORY options for CREATE TABLE are ignored on Windows, because Windows doesn't support symbolic links. These options also are ignored on systems that have a non-functional realpath() call.

DROP DATABASE

You cannot drop a database that is in use by some thread.

Case-insensitive names

Filenames are not case sensitive on Windows, so MySQL database and table names are also not case sensitive on Windows. The only restriction is that database and table names must be specified using the same case throughout a given statement. See Section 9.2.2, “Identifier Case Sensitivity”.

The ‘\’ pathname separator character

Pathname components in Windows are separated by the ‘\’ character, which is also the escape character in MySQL. If you are using LOAD DATA INFILE or SELECT ... INTO OUTFILE, use Unix-style filenames with ‘/’ characters:

mysql> LOAD DATA INFILE 'C:/tmp/skr.txt' INTO TABLE skr;
mysql> SELECT * INTO OUTFILE 'C:/tmp/skr.txt' FROM skr;

Alternatively, you must double the ‘\’ character:

mysql> LOAD DATA INFILE 'C:\\tmp\\skr.txt' INTO TABLE skr;
mysql> SELECT * INTO OUTFILE 'C:\\tmp\\skr.txt' FROM skr;

Problems with pipes

Pipes do not work reliably from the Windows command-line prompt. If the pipe includes the character ^Z / CHAR(24), Windows thinks that it has encountered end-of-file and aborts the program.

This is mainly a problem when you try to apply a binary log as follows:

C:\> mysqlbinlog binary_log_file | mysql --user=root

If you have a problem applying the log and suspect that it is because of a ^Z / CHAR(24) character, you can use the following workaround:

C:\> mysqlbinlog binary_log_file --result-file=/tmp/bin.sql
C:\> mysql --user=root --execute "source /tmp/bin.sql"

The latter command also can be used to reliably read in any SQL file that may contain binary data.

Access denied for user error

If MySQL cannot resolve your hostname properly, you may get the following error when you attempt to run a MySQL client program to connect to a server running on the same machine:

Access denied for user 'some_user'@'unknown'
to database 'mysql'

To fix this problem, you should create a file named \windows\hosts containing the following information:

127.0.0.1       localhost

Add macros to use the faster thread-safe increment/decrement methods provided by Windows.

To compile just the MySQL client libraries and client programs and not the server, use the --without-server option:

shell> ./configure --without-server

If you have no C++ compiler, some client programs such as mysql cannot be compiled because they require C++.. In this case, you can remove the code in configure that tests for the C++ compiler and then run ./configure with the --without-server option. The compile step should still try to build all clients, but you can ignore any warnings about files such as mysql.cc. (If make stops, try make -k to tell it to continue with the rest of the build even if errors occur.)

If you want to build the embedded MySQL library (libmysqld.a), use the --with-embedded-server option.

If you don't want your log files and database directories located under /usr/local/var, use a configure command something like one of these:

shell> ./configure --prefix=/usr/local/mysql
shell> ./configure --prefix=/usr/local \
           --localstatedir=/usr/local/mysql/data

The first command changes the installation prefix so that everything is installed under /usr/local/mysql rather than the default of /usr/local. The second command preserves the default installation prefix, but overrides the default location for database directories (normally /usr/local/var) and changes it to /usr/local/mysql/data.

You can also specify the installation directory and data directory locations at server startup time by using the --basedir and --datadir options. These can be given on the command line or in an MySQL option file, although it is more common to use an option file. See Section 4.3.2, “Using Option Files”.

If you are using Unix and you want the MySQL socket file location to be somewhere other than the default location (normally in the directory /tmp or /var/run), use a configure command like this:

shell> ./configure \
           --with-unix-socket-path=/usr/local/mysql/tmp/mysql.sock

The socket filename must be an absolute pathname. You can also change the location of mysql.sock at server startup by using a MySQL option file. See Section B.1.4.5, “How to Protect or Change the MySQL Unix Socket File”.

If you want to compile statically linked programs (for example, to make a binary distribution, to get better performance, or to work around problems with some Red Hat Linux distributions), run configure like this:

shell> ./configure --with-client-ldflags=-all-static \
           --with-mysqld-ldflags=-all-static

If you are using gcc and don't have libg++ or libstdc++ installed, you can tell configure to use gcc as your C++ compiler:

shell> CC=gcc CXX=gcc ./configure

When you use gcc as your C++ compiler, it does not attempt to link in libg++ or libstdc++. This may be a good thing to do even if you have those libraries installed. Some versions of them have caused strange problems for MySQL users in the past.

The following list indicates some compilers and environment variable settings that are commonly used with each one.

In most cases, you can get a reasonably optimized MySQL binary by using the options from the preceding list and adding the following options to the configure line:

--prefix=/usr/local/mysql --enable-assembler \
--with-mysqld-ldflags=-all-static

The full configure line would, in other words, be something like the following for all recent gcc versions:

CFLAGS="-O3 -mpentiumpro" CXX=gcc CXXFLAGS="-O3 -mpentiumpro \
-felide-constructors -fno-exceptions -fno-rtti" ./configure \
--prefix=/usr/local/mysql --enable-assembler \
--with-mysqld-ldflags=-all-static

The binaries we provide on the MySQL Web site at http://dev.mysql.com/downloads/ are all compiled with full optimization and should be perfect for most users. See Section 2.4.3.5, “MySQL Binaries Compiled by MySQL AB”. There are some configuration settings you can tweak to build an even faster binary, but these are only for advanced users. See Section 7.5.4, “How Compiling and Linking Affects the Speed of MySQL”.

If the build fails and produces errors about your compiler or linker not being able to create the shared library libmysqlclient.so.N (where N is a version number), you can work around this problem by giving the --disable-shared option to configure. In this case, configure does not build a shared libmysqlclient.so.N library.

By default, MySQL uses the latin1 (cp1252 West European) character set. To change the default set, use the --with-charset option:

shell> ./configure --with-charset=CHARSET

CHARSET may be one of binary, armscii8, ascii, big5, cp1250, cp1251, cp1256, cp1257, cp850, cp852, cp866, cp932, dec8, eucjpms, euckr, gb2312, gbk, geostd8, greek, hebrew, hp8, keybcs2, koi8r, koi8u, latin1, latin2, latin5, latin7, macce, macroman, sjis, swe7, tis620, ucs2, ujis, utf8. See Section 5.10.1, “The Character Set Used for Data and Sorting”. (Additional character sets might be available. Check the output from ./configure --help for the current list.)

The default collation may also be specified. MySQL uses the latin1_swedish_ci collation by default. To change this, use the --with-collation option:

shell> ./configure --with-collation=COLLATION

To change both the character set and the collation, use both the --with-charset and --with-collation options. The collation must be a legal collation for the character set. (Use the SHOW COLLATION statement to determine which collations are available for each character set.)

Warning: If you change character sets after having created any tables, you must run myisamchk -r -q --set-collation=collation_name on every MyISAM table. Your indexes may be sorted incorrectly otherwise. This can happen if you install MySQL, create some tables, and then reconfigure MySQL to use a different character set and reinstall it.

With the configure option --with-extra-charsets=LIST, you can define which additional character sets should be compiled into the server. LIST is one of the following:

Clients that want to convert characters between the server and the client should use the SET NAMES statement. See Section 13.5.3, “SET Syntax”, and Section 10.4, “Connection Character Sets and Collations”.

To configure MySQL with debugging code, use the --with-debug option:

shell> ./configure --with-debug

This causes a safe memory allocator to be included that can find some errors and that provides output about what is happening. See MySQL Internals: Porting.

As of MySQL 5.0.25, using --with-debug to configure MySQL with debugging support enables you to use the --debug="d,parser_debug" option when you start the server. This causes the Bison parser that is used to process SQL statements to dump a parser trace to the server's standard error output. Typically, this output is written to the error log.

If your client programs are using threads, you must compile a thread-safe version of the MySQL client library with the --enable-thread-safe-client configure option. This creates a libmysqlclient_r library with which you should link your threaded applications. See Section 22.2.16, “How to Make a Threaded Client”.

It is possible to build MySQL 5.0 with large table support using the --with-big-tables option, beginning with MySQL 5.0.4.

This option causes the variables that store table row counts to be declared as unsigned long long rather than unsigned long. This enables tables to hold up to approximately 1.844E+19 ((2³²)²) rows rather than 2³² (~4.295E+09) rows. Previously it was necessary to pass -DBIG_TABLES to the compiler manually in order to enable this feature.

Run configure with the --disable-grant-options option to cause the the --bootstrap, --skip-grant-tables, and --init-file options for mysqld to be disabled. For Windows, the configure.js script recognizes the DISABLE_GRANT_OPTIONS flag, which has the same effect. The capability is available as of MySQL 5.0.34.

See Section 2.4.18, “Operating System-Specific Notes”, for options that pertain to particular operating systems.

See Section 5.8.7.2, “Using SSL Connections”, for options that pertain to configuring MySQL to support secure (encrypted) connections.

If configure is run after it has previously been run, it may use information that was gathered during its previous invocation. This information is stored in config.cache. When configure starts up, it looks for that file and reads its contents if it exists, on the assumption that the information is still correct. That assumption is invalid when you reconfigure.

Each time you run configure, you must run make again to recompile. However, you may want to remove old object files from previous builds first because they were compiled using different configuration options.

If you get errors such as the ones shown here when compiling sql_yacc.cc, you probably have run out of memory or swap space:

Internal compiler error: program cc1plus got fatal signal 11
Out of virtual memory
Virtual memory exhausted

The problem is that gcc requires a huge amount of memory to compile sql_yacc.cc with inline functions. Try running configure with the --with-low-memory option:

shell> ./configure --with-low-memory

This option causes -fno-inline to be added to the compile line if you are using gcc and -O0 if you are using something else. You should try the --with-low-memory option even if you have so much memory and swap space that you think you can't possibly have run out. This problem has been observed to occur even on systems with generous hardware configurations, and the --with-low-memory option usually fixes it.

By default, configure picks c++ as the compiler name and GNU c++ links with -lg++. If you are using gcc, that behavior can cause problems during configuration such as this:

configure: error: installation or configuration problem:
C++ compiler cannot create executables.

You might also observe problems during compilation related to g++, libg++, or libstdc++.

One cause of these problems is that you may not have g++, or you may have g++ but not libg++, or libstdc++. Take a look at the config.log file. It should contain the exact reason why your C++ compiler didn't work. To work around these problems, you can use gcc as your C++ compiler. Try setting the environment variable CXX to "gcc -O3". For example:

shell> CXX="gcc -O3" ./configure

This works because gcc compiles C++ source files as well as g++ does, but does not link in libg++ or libstdc++ by default.

Another way to fix these problems is to install g++, libg++, and libstdc++. However, we recommend that you not use libg++ or libstdc++ with MySQL because this only increases the binary size of mysqld without providing any benefits. Some versions of these libraries have also caused strange problems for MySQL users in the past.

If your compile fails with errors such as any of the following, you must upgrade your version of make to GNU make:

making all in mit-pthreads
make: Fatal error in reader: Makefile, line 18:
Badly formed macro assignment

Or:

make: file `Makefile' line 18: Must be a separator (:

Or:

pthread.h: No such file or directory

Solaris and FreeBSD are known to have troublesome make programs.

GNU make 3.75 is known to work.

If you want to define flags to be used by your C or C++ compilers, do so by adding the flags to the CFLAGS and CXXFLAGS environment variables. You can also specify the compiler names this way using CC and CXX. For example:

shell> CC=gcc
shell> CFLAGS=-O3
shell> CXX=gcc
shell> CXXFLAGS=-O3
shell> export CC CFLAGS CXX CXXFLAGS

See Section 2.4.3.5, “MySQL Binaries Compiled by MySQL AB”, for a list of flag definitions that have been found to be useful on various systems.

If you get errors such as those shown here when compiling mysqld, configure did not correctly detect the type of the last argument to accept(), getsockname(), or getpeername():

cxx: Error: mysqld.cc, line 645: In this statement, the referenced
     type of the pointer value ''length'' is ''unsigned long'',
     which is not compatible with ''int''.
new_sock = accept(sock, (struct sockaddr *)&cAddr, &length);

To fix this, edit the config.h file (which is generated by configure). Look for these lines:

/* Define as the base type of the last arg to accept */
#define SOCKET_SIZE_TYPE XXX

Change XXX to size_t or int, depending on your operating system. (You must do this each time you run configure because configure regenerates config.h.)

The sql_yacc.cc file is generated from sql_yacc.yy. Normally, the build process does not need to create sql_yacc.cc because MySQL comes with a pre-generated copy. However, if you do need to re-create it, you might encounter this error:

"sql_yacc.yy", line xxx fatal: default action causes potential...

This is a sign that your version of yacc is deficient. You probably need to install bison (the GNU version of yacc) and use that instead.

On Debian Linux 3.0, you need to install gawk instead of the default mawk if you want to compile MySQL with Berkeley DB support.

If you need to debug mysqld or a MySQL client, run configure with the --with-debug option, and then recompile and link your clients with the new client library. See MySQL Internals: Porting.

If you get a compilation error on Linux (for example, SuSE Linux 8.1 or Red Hat Linux 7.3) similar to the following one, you probably do not have g++ installed:

libmysql.c:1329: warning: passing arg 5 of `gethostbyname_r' from
incompatible pointer type
libmysql.c:1329: too few arguments to function `gethostbyname_r'
libmysql.c:1329: warning: assignment makes pointer from integer
without a cast
make[2]: *** [libmysql.lo] Error 1

By default, the configure script attempts to determine the correct number of arguments by using g++ (the GNU C++ compiler). This test yields incorrect results if g++ is not installed. There are two ways to work around this problem:

You must run configure again after making either of those changes.

On most systems, you can force MIT-pthreads to be used by running configure with the --with-mit-threads option:

shell> ./configure --with-mit-threads

Building in a non-source directory is not supported when using MIT-pthreads because we want to minimize our changes to this code.

The checks that determine whether to use MIT-pthreads occur only during the part of the configuration process that deals with the server code. If you have configured the distribution using --without-server to build only the client code, clients do not know whether MIT-pthreads is being used and use Unix socket file connections by default. Because Unix socket files do not work under MIT-pthreads on some platforms, this means you need to use -h or --host with a value other than localhost when you run client programs.

When MySQL is compiled using MIT-pthreads, system locking is disabled by default for performance reasons. You can tell the server to use system locking with the --external-locking option. This is needed only if you want to be able to run two MySQL servers against the same data files, but that is not recommended, anyway.

Sometimes the pthread bind() command fails to bind to a socket without any error message (at least on Solaris). The result is that all connections to the server fail. For example:

shell> mysqladmin version
mysqladmin: connect to server at '' failed;
error: 'Can't connect to mysql server on localhost (146)'

The solution to this problem is to kill the mysqld server and restart it. This has happened to us only when we have forcibly stopped the server and restarted it immediately.

With MIT-pthreads, the sleep() system call isn't interruptible with SIGINT (break). This is noticeable only when you run mysqladmin --sleep. You must wait for the sleep() call to terminate before the interrupt is served and the process stops.

When linking, you might receive warning messages like these (at least on Solaris); they can be ignored:

ld: warning: symbol `_iob' has differing sizes:
    (file /my/local/pthreads/lib/libpthread.a(findfp.o) value=0x4;
file /usr/lib/libc.so value=0x140);
    /my/local/pthreads/lib/libpthread.a(findfp.o) definition taken
ld: warning: symbol `__iob' has differing sizes:
    (file /my/local/pthreads/lib/libpthread.a(findfp.o) value=0x4;
file /usr/lib/libc.so value=0x140);
    /my/local/pthreads/lib/libpthread.a(findfp.o) definition taken

Some other warnings also can be ignored:

implicit declaration of function `int strtoll(...)'
implicit declaration of function `int strtoul(...)'

We have not been able to make readline work with MIT-pthreads. (This is not necessary, but may be of interest to some.)

Windows 2000, Windows XP, or newer version. Windows Vista is not supported until Microsoft certifies Visual Studio 2005 on Vista.

CMake, which can be downloaded from http://www.cmake.org. After installing, modify your path to include the cmake binary.

Microsoft Visual C++ 2005 Express Edition, Visual Studio .Net 2003 (7.1), or Visual Studio 2005 (8.0) compiler system.

If you are using Visual C++ 2005 Express Edition, you must also install an appropriate Platform SDK. More information and links to downloads for various Windows platforms is available from http://msdn.microsoft.com/platformsdk/.

If you are compiling from a BitKeeper tree or making changes to the parser, you need bison for Windows, which can be downloaded from http://gnuwin32.sourceforge.net/packages/bison.htm. Download the package labeled “Complete package, excluding sources”. After installing the package, modify your path to include the bison binary and ensure that this binary is accessible from Visual Studio.

Cygwin might be necessary if you want to run the test script or package the compiled binaries and support files into a Zip archive. (Cygwin is needed only to test or package the distribution, not to build it.) Cygwin is available from http://cygwin.com.

3GB to 5GB of disk space.

Obtain a Windows source distribution packaged by MySQL AB for the particular version of MySQL in which you are interested. These are available from http://dev.mysql.com/downloads/.

Package a source distribution yourself from the latest BitKeeper developer source tree. If you plan to do this, and you are not using the CMake build method, you must create the package on a Unix system and then transfer it to your Windows system. (Some of the configuration and build steps require tools that work only on Unix.) Thus, if you are not using CMake, the BitKeeper approach requires:

If you install MySQL on Linux using RPM distributions, the server RPM runs mysql_install_db.

If you install MySQL on Mac OS X using a PKG distribution, the installer runs mysql_install_db.

Windows distributions contain preinitialized grant tables that are installed automatically.

On Unix, the grant tables are populated by the mysql_install_db program. Some installation methods run this program for you. Others require that you execute it manually. For details, see Section 2.4.15.2, “Unix Post-Installation Procedures”.

Accounts with the username root are created. These are superuser accounts that can do anything. The initial root account passwords are empty, so anyone can connect to the MySQL server as root — without a password — and be granted all privileges.

Two anonymous-user accounts are created, each with an empty username. The anonymous accounts have no password, so anyone can use them to connect to the MySQL server.

If you want to prevent clients from connecting as anonymous users without a password, you should either assign a password to each anonymous account or else remove the accounts.

You should assign a password to each MySQL root account.

Use the SET PASSWORD statement

Use the mysqladmin command-line client program

Use the UPDATE statement

Check the items in Section 2.4.16, “Upgrading MySQL”, to see whether any of them might affect your applications.

Check the items in the change lists found later in this section to see whether any of them might affect your applications. Note particularly any that are marked Incompatible change. These result in incompatibilities with earlier versions of MySQL, and may require your attention before you upgrade.

Some releases of MySQL introduce incompatible changes to tables. (Our aim is to avoid these changes, but occasionally they are necessary to correct problems that would be worse than an incompatibility between releases.) Some releases of MySQL introduce changes to the structure of the grant tables to add new privileges or features.

To avoid problems due to such changes, after you upgrade to a new version of MySQL, you should check your tables (and repair them if necessary), and update your grant tables to make sure that they have the current structure so that you can take advantage of any new capabilities. See Section 5.5.8, “mysql_upgrade — Check Tables for MySQL Upgrade”.

Read the MySQL 5.0 change history to see what significant new features you can use in 5.0. See Section E.1, “Changes in release 5.0.x (Production)”.

If you are running MySQL Server on Windows, see Section 2.4.8.14, “Upgrading MySQL on Windows”.

MySQL 5.0 adds support for stored procedures. This support requires the mysql.proc table. To create this table, you should run the mysql_upgrade program as described in Section 5.5.8, “mysql_upgrade — Check Tables for MySQL Upgrade”.

MySQL 5.0 adds support for views. This support requires extra privilege columns in the mysql.user and mysql.db tables. To create these columns, you should run the mysql_upgrade program as described in Section 5.5.8, “mysql_upgrade — Check Tables for MySQL Upgrade”.

If you are using replication, see Section 6.6, “Upgrading a Replication Setup”, for information on upgrading your replication setup.

Incompatible change: The indexing order for end-space in TEXT columns for InnoDB and MyISAM tables has changed. Starting from 5.0.3, TEXT indexes are compared as space-padded at the end (just as MySQL sorts CHAR, VARCHAR and TEXT fields). If you have a index on a TEXT column, you should run CHECK TABLE on it. If the check reports errors, rebuild the indexes: Dump and reload the table if it is an InnoDB table, or run OPTIMIZE TABLE or REPAIR TABLE if it is a MyISAM table.

Incompatible change. For BINARY columns, the pad value and how it is handled has changed as of MySQL 5.0.15. The pad value for inserts now is 0x00 rather than space, and there is no stripping of the pad value for retrievals. For details, see Section 11.4.2, “The BINARY and VARBINARY Types”.

Incompatible change: As of MySQL 5.0.3, the server by default no longer loads user-defined functions (UDFs) unless they have at least one auxiliary symbol (for example, an xxx_init or xxx_deinit symbol) defined in addition to the main function symbol. This behavior can be overridden with the --allow-suspicious-udfs option. See Section 24.2.4.6, “User-Defined Function Security Precautions”.

Incompatible change: Previously, a lock wait timeout caused InnoDB to roll back the entire current transaction. As of MySQL 5.0.13, it rolls back only the most recent SQL statement.

Incompatible change: For ENUM columns that had enumeration values containing commas, the commas were mapped to 0xff internally. However, this rendered the commas indistinguishable from true 0xff characters in the values. This no longer occurs. However, the fix requires that you dump and reload any tables that have ENUM columns containing true 0xff in their values: Dump the tables using mysqldump with the current server before upgrading from a version of MySQL 5.0 older than 5.0.36 to version 5.0.36 or newer.

Incompatible change: The update log has been removed in MySQL 5.0. If you had enabled it previously, you should enable the binary log instead.

Incompatible change: Support for the ISAM storage engine has been removed in MySQL 5.0. If you have any ISAM tables, you should convert them before upgrading. For example, to convert an ISAM table to use the MyISAM storage engine, use this statement:

ALTER TABLE tbl_name ENGINE = MyISAM;

Use a similar statement for every ISAM table in each of your databases.

Incompatible change: Support for RAID options in MyISAM tables has been removed in MySQL 5.0. If you have tables that use these options, you should convert them before upgrading. One way to do this is to dump them with mysqldump, edit the dump file to remove the RAID options in the CREATE TABLE statements, and reload the dump file. Another possibility is to use CREATE TABLE new_tbl ... SELECT raid_tbl to create a new table from the RAID table. However, the CREATE TABLE part of the statement must contain sufficient information to re-create column attributes as well as indexes, or column attributes may be lost and indexes will not appear in the new table. See Section 13.1.5, “CREATE TABLE Syntax”.

The .MYD files for RAID tables in a given database are stored under the database directory in subdirectories that have names consisting of two hex digits in the range from 00 to ff. After converting all tables that use RAID options, these RAID-related subdirectories still will exist but can be removed. Verify that they are empty, and then remove them manually. (If they are not empty, there is some RAID table that has not been converted.)

As of MySQL 5.0.25, the lc_time_names system variable specifies the locale that controls the language used to display day and month names and abbreviations. This variable affects the output from the DATE_FORMAT(), DAYNAME() and MONTHNAME() functions. See Section 5.10.9, “MySQL Server Locale Support”.

In MySQL 5.0.6, binary logging of stored routines and triggers was changed. This change has implications for security, replication, and data recovery, as discussed in Section 17.4, “Binary Logging of Stored Routines and Triggers”.

As of MySQL 5.0.28, mysqld_safe no longer implicitly invokes mysqld-max if it exists. Instead, it invokes mysqld unless a --mysqld or --mysqld-version option is given to specify another server explicitly. If you previously relied on the implicit invocation of mysqld-max, you should use an appropriate option now.

Incompatible change: Beginning with MySQL 5.0.12, natural joins and joins with USING, including outer join variants, are processed according to the SQL:2003 standard. The changes include elimination of redundant output columns for NATURAL joins and joins specified with a USING clause and proper ordering of output columns. The precedence of the comma operator also now is lower compared to JOIN, LEFT JOIN, and so forth.

These changes make MySQL more compliant with standard SQL. However, they can result in different output columns for some joins. Also, some queries that appeared to work correctly prior to 5.0.12 must be rewritten to comply with the standard. For details about the scope of the changes and examples that show what query rewrites are necessary, see Section 13.2.7.1, “JOIN Syntax”.

Incompatible change: The namespace for triggers has changed in MySQL 5.0.10. Previously, trigger names had to be unique per table. Now they must be unique within the schema (database). An implication of this change is that DROP TRIGGER syntax now uses a schema name instead of a table name (schema name is optional and, if omitted, the current schema will be used).

When upgrading from a previous version of MySQL 5 to MySQL 5.0.10 or newer, you must drop all triggers and re-create them or DROP TRIGGER will not work after the upgrade. Here is a suggested procedure for doing this:

Incompatible change: As of MySQL 5.0.15, the CHAR() function returns a binary string rather than a string in the connection character set. An optional USING charset_name clause may be used to produce a result in a specific character set instead. Also, arguments larger than 256 produce multiple characters. They are no longer interpreted modulo 256 to produce a single character each. These changes may cause some incompatibilities:

Incompatible change: By default, integer subtraction involving an unsigned value should produce an unsigned result. Tracking of the “unsignedness” of an expression was improved in MySQL 5.0.13. This means that, in some cases where an unsigned subtraction would have resulted in a signed integer, it now results in an unsigned integer. One context in which this difference manifests itself is when a subtraction involving an unsigned operand would be negative.

Suppose that i is a TINYINT UNSIGNED column and has a value of 0. The server evaluates the following expression using 64-bit unsigned integer arithmetic with the following result:

mysql> SELECT i - 1 FROM t;
+----------------------+
| i - 1                |
+----------------------+
| 18446744073709551615 |
+----------------------+

If the expression is used in an UPDATE t SET i = i - 1 statement, the expression is evaluated and the result assigned to i according to the usual rules for handling values outside the column range or 0 to 255. That is, the value is clipped to the nearest endpoint of the range. However, the result is version-specific:

To get the older behavior, use CAST() to convert the expression result to a signed value:

UPDATE t SET i = CAST(i - 1 AS SIGNED);

Alternatively, set the NO_UNSIGNED_SUBTRACTION SQL mode. However, this will affect all integer subtractions involving unsigned values.

Incompatible change: Before MySQL 5.0.13, NOW() and SYSDATE() return the same value (the time at which the statement in which the function occurs begins executing). As of MySQL 5.0.13, SYSDATE() returns the time at which it it executes, which can differ from the value returned by NOW(). For information about the implications for binary logging and replication, see the description for SYSDATE() in Section 12.6, “Date and Time Functions” and for SET TIMESTAMP in Section 13.5.3, “SET Syntax”. To restore the former behavior for SYSDATE() and cause it to be an alias for NOW(), start the server with the --sysdate-is-now option (available as of MySQL 5.0.20).

Incompatible change: Before MySQL 5.0.13, GREATEST(x,NULL) and LEAST(x,NULL) return x when x is a non-NULL value. As of 5.0.3, both functions return NULL if any argument is NULL, the same as Oracle. This change can cause problems for applications that rely on the old behavior.

Incompatible change: Before MySQL 4.1.13/5.0.8, conversion of DATETIME values to numeric form by adding zero produced a result in YYYYMMDDHHMMSS format. The result of DATETIME+0 is now in YYYYMMDDHHMMSS.000000 format.

Incompatible change: In MySQL 4.1.12/5.0.6, the behavior of LOAD DATA INFILE and SELECT ... INTO OUTFILE has changed when the FIELDS TERMINATED BY and FIELDS ENCLOSED BY values both are empty. Formerly, a column was read or written the display width of the column. For example, INT(4) was read or written using a field with a width of 4. Now columns are read and written using a field width wide enough to hold all values in the field. However, data files written before this change was made might not be reloaded correctly with LOAD DATA INFILE for MySQL 4.1.12/5.0.6 and up. This change also affects data files read by mysqlimport and written by mysqldump --tab, which use LOAD DATA INFILE and SELECT ... INTO OUTFILE. For more information, see Section 13.2.5, “LOAD DATA INFILE Syntax”.

Incompatible change: The implementation of DECIMAL has changed in MySQL 5.0.3. You should make your applications aware of this change. For information about this change, and about possible incompatibilities with old applications, see Chapter 21, Precision Math.

DECIMAL columns are stored in a more efficient format. To convert a table to use the new DECIMAL type, you should do an ALTER TABLE on it. (The ALTER TABLE also will change the table's VARCHAR columns to use the new VARCHAR data type properties, described in a separate item.)

A consequence of the change in handling of the DECIMAL and NUMERIC fixed-point data types is that the server is more strict to follow standard SQL. For example, a data type of DECIMAL(3,1) stores a maximum value of 99.9. Before MySQL 5.0.3, the server allowed larger numbers to be stored. That is, it stored a value such as 100.0 as 100.0. As of MySQL 5.0.3, the server clips 100.0 to the maximum allowable value of 99.9. If you have tables that were created before MySQL 5.0.3 and that contain floating-point data not strictly legal for the data type, you should alter the data types of those columns. For example:

ALTER TABLE tbl_name MODIFY col_name DECIMAL(4,1);

The behavior used by the server for DECIMAL columns in a table depends on the version of MySQL used to create the table. If your server is from MySQL 5.0.3 or higher, but you have DECIMAL columns in tables that were created before 5.0.3, the old behavior still applies to those columns. To convert the tables to the newer DECIMAL format, dump them with mysqldump and reload them.

Incompatible change: MySQL 5.0.3 and up uses precision math when calculating with DECIMAL and integer columns (64 decimal digits) and for rounding exact-value numbers. Rounding behavior is well-defined, not dependent on the implementation of the underlying C library. However, this might result in incompatibilities for applications that rely on the old behavior. (For example, inserting .5 into an INT column results in 1 as of MySQL 5.0.3, but might be 0 in older versions.) For more information about rounding behavior, see Section 21.4, “Rounding Behavior”, and Section 21.5, “Precision Math Examples”.

Incompatible change: MyISAM and InnoDB tables created with DECIMAL columns in MySQL 5.0.3 to 5.0.5 will appear corrupt after an upgrade to MySQL 5.0.6. (The same incompatibility will occur for these tables created in MySQL 5.0.6 after a downgrade to MySQL 5.0.3 to 5.0.5.) If you have such tables, check and repair them with mysql_upgrade after upgrading. See Section 5.5.8, “mysql_upgrade — Check Tables for MySQL Upgrade”.

Incompatible change: For user-defined functions, exact-value decimal arguments such as 1.3 or DECIMAL column values were passed as REAL_RESULT values prior to MySQL 5.0.3. As of 5.0.3, they are passed as strings with a type of DECIMAL_RESULT. If you upgrade to 5.0.3 and find that your UDF now receives string values, use the initialization function to coerce the arguments to numbers as described in Section 24.2.4.3, “UDF Argument Processing”.

Incompatible change: Before MySQL 5.0.2, SHOW STATUS returned global status values. The default as of 5.0.2 is to return session values, which is incompatible with previous versions. To issue a SHOW STATUS statement that will retrieve global status values for all versions of MySQL, write it like this:

SHOW /*!50002 GLOBAL */ STATUS;

Incompatible change: User variables are not case sensitive in MySQL 5.0. In MySQL 4.1, SET @x = 0; SET @X = 1; SELECT @x; created two variables and returned 0. In MySQL 5.0, it creates one variable and returns 1. Replication setups that rely on the old behavior may be affected by this change.

Some keywords are reserved in MySQL 5.0 that were not reserved in MySQL 4.1. See Section 9.3, “Reserved Words”.

The LOAD DATA FROM MASTER and LOAD TABLE FROM MASTER statements are deprecated. See Section 13.6.2.2, “LOAD DATA FROM MASTER Syntax”, for recommended alternatives.

As of MySQL 5.0.3, trailing spaces no longer are removed from values stored in VARCHAR and VARBINARY columns. The maximum lengths for VARCHAR and VARBINARY columns in MySQL 5.0.3 and later are 65,535 characters and 65,535 bytes, respectively.

When a binary upgrade (filesystem-level copy of data files) to MySQL 5.0 is performed for a table with a VARBINARY column, the column is space-padded to the full allowable width of the column. This causes values in VARBINARY columns that do not occupy the full width of the column to include extra trailing spaces after the upgrade, which means that the data in the column is different.

In addition, new rows inserted into a table upgraded in this way will be space padded to the full width of the column.

This issue can be resolved as follows:

This problem does not occur (and thus these two steps are not required) for tables upgraded using the recommended procedure of dumping tables prior to the upgrade and reloading them afterwards.

Note: If you create a table with new VARCHAR or VARBINARY columns in MySQL 5.0.3 or later, the table will not be usable if you downgrade to a version older than 5.0.3. Dump the table with mysqldump before downgrading and reload it after downgrading.

Comparisons made between FLOAT or DOUBLE values that happened to work in MySQL 4.1 may not do so in 5.0. Values of these types are imprecise in all MySQL versions, and you are strongly advised to avoid such comparisons as WHERE col_name=some_double, regardless of the MySQL version you are using. See Section B.1.5.8, “Problems with Floating-Point Comparisons”.

As of MySQL 5.0.3, BIT is a separate data type, not a synonym for TINYINT(1). See Section 11.1.1, “Overview of Numeric Types”.

MySQL 5.0.2 adds several SQL modes that allow stricter control over rejecting records that have invalid or missing values. See Section 5.2.6, “SQL Modes”, and Section 1.9.6.2, “Constraints on Invalid Data”. If you want to enable this control but continue to use MySQL's capability for storing incorrect dates such as '2004-02-31', you should start the server with --sql_mode="TRADITIONAL,ALLOW_INVALID_DATES".

As of MySQL 5.0.2, the SCHEMA and SCHEMAS keywords are accepted as synonyms for DATABASE and DATABASES, respectively. (While “schemata” is grammatically correct and even appears in some MySQL 5.0 system database and table names, it cannot be used as a keyword.)

As of MySQL 5.0.25, TIMESTAMP columns that are NOT NULL now are reported that way by SHOW COLUMNS and INFORMATION_SCHEMA, rather than as NULL.

Incompatible change: Because the MySQL 5.0 server has a new implementation of the DECIMAL data type, a problem may occur if the server is used by older clients that still are linked against MySQL 4.1 client libraries. If a client uses the binary client/server protocol to execute prepared statements that generate result sets containing numeric values, an error will be raised: 'Using unsupported buffer type: 246'

This error occurs because the 4.1 client libraries do not support the new MYSQL_TYPE_NEWDECIMAL type value added in 5.0. There is no way to disable the new DECIMAL data type on the server side. You can avoid the problem by relinking the application with the client libraries from MySQL 5.0.

Incompatible change: The ER_WARN_DATA_TRUNCATED warning symbol was renamed to WARN_DATA_TRUNCATED in MySQL 5.0.3.

The reconnect flag in the MYSQL structure is set to 0 by mysql_real_connect(). Only those client programs which did not explicitly set this flag to 0 or 1 after mysql_real_connect() experience a change. Having automatic reconnection enabled by default was considered too dangerous (due to the fact that table locks, temporary tables, user variables, and session variables are lost after reconnection).