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4 Installing MySQL

This chapter describes how to obtain and install MySQL:

4.1 How to Get MySQL

Check the MySQL home page for information about the current version and for downloading instructions.

Our main download mirror is located at:

http://download.sourceforge.net/mirrors/mysql/

If you are interested in becoming a MySQL mirror site, you may anonymously rsync with: rsync://download.sourceforge.net/mysql/. Please send e-mail to webmaster@mysql.com notifying us of your mirror to be added to the list below.

If you have problems downloading from our main site, try using one of the mirrors listed below.

Please report bad or out-of-date mirrors to webmaster@mysql.com.

Europe:

North America:

South America:

Asia:

Australia:

Africa:

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 - 2.7) and SuSE Linux Version 7.x.

Note that for many operating systems, the native thread support works only in the latest versions. MySQL has been reported to compile successfully on the following operating system/thread package combinations:

Note that not all platforms are suited equally well for running MySQL. How well a certain platform is suited for a high-load mission critical MySQL server is determined by the following factors:

Based on the above criteria, the best platforms for running MySQL at this point are x86 with SuSE Linux 7.1, 2.4 kernel and ReiserFS (or any similar Linux distribution) and Sparc with Solaris 2.7 or 2.8. FreeBSD comes third, but we really hope it will join the top club once the thread library is improved. We also hope that at some point we will be able to include all other platforms on which MySQL compiles, runs ok, but not quite with the same level of stability and performance, into the top category. This will require some effort on our part in cooperation with the developers of the OS/library components MySQL depends upon. If you are interested in making one of those components better, are in a position to influence their development, and need more detailed instructions on what MySQL needs to run better, send an e-mail to internals@lists.mysql.com.

Please note that the comparison above is not to say that one OS is better or worse than the other in general. We are talking about choosing a particular OS for a dedicated purpose - running MySQL, and compare platforms in that regard only. With this in mind, the result of this comparison would be different if we included more issues into it. And in some cases, the reason one OS is better than the other could simply be that we have put forth more effort into testing on and optimizing for that particular platform. We are just stating our observations to help you make a decision on which platform to use MySQL on in your setup.

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:

The second decision to make is whether you want to use a source distribution or a binary distribution. In most cases you should probably use a binary distribution, if one exists for your platform, as this generally will be easier to install than a source distribution.

In the following cases you probably will be better off with a source installation:

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:

All versions of MySQL are run through our standard tests and benchmarks to ensure that they are relatively safe to use. Because 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 13.7 Using Your Own Benchmarks.
The crash-me test
This tries to determine what features the database supports and what its capabilities and limitations are. See section 13.7 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 MySQL AB 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 take note of what our licensed users want to have, and we especially take note of what our extended e-mail 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 F MySQL change history.

We use the following policy when updating MySQL:

The current stable release is Version 3.23; We have already moved active development to Version 4.0. Bugs will still be fixed in the stable version. We don't believe in a complete freeze, as this also leaves out bug fixes and things that ``must be done.'' ``Somewhat frozen'' means that we may add small things that ``almost surely will not affect anything that's already working.''

4.5 Installation Layouts

This section describes the default layout of the directories created by installing binary and source distributions.

A binary distribution is installed by unpacking it at the installation location you choose (typically `/usr/local/mysql') and creates the following directories in that location:

Directory Contents of directory
`bin' Client programs and the mysqld server
`data' Log files, databases
`include' Include (header) files
`lib' Libraries
`scripts' mysql_install_db
`share/mysql' Error message files
`sql-bench' Benchmarks

A source distribution is installed after you configure and compile it. By default, the installation step installs files under `/usr/local', in the following subdirectories:

Directory Contents of directory
`bin' Client programs and scripts
`include/mysql' Include (header) files
`info' Documentation in Info format
`lib/mysql' Libraries
`libexec' The mysqld server
`share/mysql' Error message files
`sql-bench' Benchmarks and crash-me test
`var' Databases and log files

Within an installation directory, the layout of a source installation differs from that of a binary installation in the following ways:

You can create your own binary installation from a compiled source distribution by executing the script `scripts/make_binary_distribution'.

4.6 Installing a MySQL Binary Distribution

You need the following tools to install a MySQL binary distribution:

An alternative installation method under Linux is to use RPM (RedHat Package Manager) distributions. See section 4.6.1 Linux RPM Notes.

If you run into problems, PLEASE ALWAYS USE mysqlbug when posting questions to mysql@lists.mysql.com. Even if the problem isn't a bug, mysqlbug gathers system information that will help others solve your problem. By not using mysqlbug, you lessen the likelihood of getting a solution to your problem! You will find mysqlbug in the `bin' directory after you unpack the distribution. See section 2.3 How to Report Bugs or Problems.

The basic commands you must execute to install and use a MySQL binary distribution are: 

shell> groupadd mysql
shell> useradd -g mysql mysql
shell> cd /usr/local
shell> gunzip < /path/to/mysql-VERSION-OS.tar.gz | tar xvf -
shell> ln -s mysql-VERSION-OS mysql
shell> cd mysql
shell> scripts/mysql_install_db
shell> chown -R root  /usr/local/mysql
shell> chown -R mysql /usr/local/mysql/data
shell> chgrp -R mysql /usr/local/mysql
shell> chown -R root /usr/local/mysql/bin
shell> bin/safe_mysqld --user=mysql &

You can add new users using the bin/mysql_setpermission script if you install the DBI and Msql-Mysql-modules Perl modules.

A more detailed description follows.

To install a binary distribution, follow the steps below, then proceed to section 4.16 Post-installation Setup and Testing, for post-installation setup and testing:

  1. Pick the directory under which you want to unpack the distribution, and move into it. In the example below, we unpack the distribution under `/usr/local' and create a directory `/usr/local/mysql' into which MySQL is installed. (The following instructions therefore assume you have permission to create files in `/usr/local'. If that directory is protected, you will need to perform the installation as root.)
  2. Obtain a distribution file from one of the sites listed in section 4.1 How to Get MySQL. MySQL binary distributions are provided as compressed tar archives and have names like `mysql-VERSION-OS.tar.gz', where VERSION is a number (for example, 3.21.15), and OS indicates the type of operating system for which the distribution is intended (for example, pc-linux-gnu-i586).
  3. If you see a binary distribution marked with the -max prefix, this means that the binary has support for transaction-safe tables and other features. See section 15.2 mysqld-max, An extended mysqld server. Note that all binaries are built from the same MySQL source distribution.
  4. Add a user and group for mysqld to run as: 
    shell> groupadd mysql
shell> useradd -g mysql mysql
    These commands add the mysql group and the mysql user. The syntax for useradd and groupadd may differ slightly on different versions of Unix. They may also be called adduser and addgroup. You may wish to call the user and group something else instead of mysql.
  5. Change into the intended installation directory: 
    shell> cd /usr/local
  6. Unpack the distribution and create the installation directory: 
    shell> gunzip < /path/to/mysql-VERSION-OS.tar.gz | tar xvf -
shell> ln -s mysql-VERSION-OS mysql
    The first command creates a directory named `mysql-VERSION-OS'. The second command makes a symbolic link to that directory. This lets you refer more easily to the installation directory as `/usr/local/mysql'.
  7. Change into the installation directory: 
    shell> cd mysql
    You will find several files and subdirectories in the mysql directory. The most important for installation purposes are the `bin' and `scripts' subdirectories.
    `bin'
    This directory contains client programs and the server You should add the full pathname of this directory to your PATH environment variable so that your shell finds the MySQL programs properly. See section A Environment Variables.
    `scripts'
    This directory contains the mysql_install_db script used to initialize the mysql database containing the grant tables that store the server access permissions.
  8. If you would like to use mysqlaccess and have the MySQL distribution in some non-standard place, you must change the location where mysqlaccess expects to find the mysql client. Edit the `bin/mysqlaccess' script at approximately line 18. Search for a line that looks like this: 
    $MYSQL     = '/usr/local/bin/mysql';    # path to mysql executable
    Change the path to reflect the location where mysql actually is stored on your system. If you do not do this, you will get a Broken pipe error when you run mysqlaccess.
  9. Create the MySQL grant tables (necessary only if you haven't installed MySQL before): 
    shell> scripts/mysql_install_db
    Note that MySQL versions older than Version 3.22.10 started the MySQL server when you run mysql_install_db. This is no longer true!
  10. Change ownership of binaries to root and ownership of the data directory to the user that you will run mysqld as: 
    shell> chown -R root  /usr/local/mysql
shell> chown -R mysql /usr/local/mysql/data
shell> chgrp -R mysql /usr/local/mysql
    The first command changes the owner attribute of the files to the root user, the second one changes the owner attribute of the data directory to the mysql user, and the third one changes the group attribute to the mysql group.
  11. If you want to install support for the Perl DBI/DBD interface, see section 4.11 Perl Installation Comments.
  12. If you would like MySQL to start automatically when you boot your machine, you can copy support-files/mysql.server to the location where your system has its startup files. More information can be found in the support-files/mysql.server script itself and in section 4.16.3 Starting and Stopping MySQL Automatically.

After everything has been unpacked and installed, you should initialize and test your distribution.

You can start the MySQL server with the following command: 

shell> bin/safe_mysqld --user=mysql &

See section 15.3 safe_mysqld, the wrapper around mysqld.

See section 4.16 Post-installation Setup and Testing.

4.6.1 Linux RPM Notes

The recommended way to install MySQL on Linux is by using an RPM file. The MySQL RPMs are currently being built on a RedHat Version 6.2 system but should work on other versions of Linux that support rpm and use glibc.

If you have problems with an RPM file, for example, if you receive the error ``Sorry, the host 'xxxx' could not be looked up'', see section 4.6.3.1 Linux Notes for Binary Distributions.

The RPM files you may want to use are:

To see all files in an RPM package, run: 

shell> rpm -qpl MySQL-VERSION.i386.rpm

To perform a standard minimal installation, run: 

shell> rpm -i MySQL-VERSION.i386.rpm MySQL-client-VERSION.i386.rpm

To install just the client package, run: 

shell> rpm -i MySQL-client-VERSION.i386.rpm

The RPM places data in `/var/lib/mysql'. The RPM also creates the appropriate entries in `/etc/rc.d/' to start the server automatically at boot time. (This means that if you have performed a previous installation, you may want to make a copy of your previously installed MySQL startup file if you made any changes to it, so you don't lose your changes.)

After installing the RPM file(s), the mysqld daemon should be running and you should now be able to start using MySQL. See section 4.16 Post-installation Setup and Testing.

If something goes wrong, you can find more information in the binary installation chapter. See section 4.6 Installing a MySQL Binary Distribution.

4.6.2 Building Client Programs

If you compile MySQL clients that you've written yourself or that you obtain from a third party, they must be linked using the -lmysqlclient -lz option on the link command. You may also need to specify a -L option to tell the linker where to find the library. For example, if the library is installed in `/usr/local/mysql/lib', use -L/usr/local/mysql/lib -lmysqlclient -lz on the link command.

For clients that use MySQL header files, you may need to specify a -I option when you compile them (for example, -I/usr/local/mysql/include), so the compiler can find the header files.

4.6.3 System-specific Issues

The following sections indicate some of the issues that have been observed on particular systems when installing MySQL from a binary distribution or from RPM files.

4.6.3.1 Linux Notes for Binary Distributions

MySQL needs at least Linux Version 2.0.

The binary release is linked with -static, which means you do not normally need to worry about which version of the system libraries you have. You need not install LinuxThreads, either. A program linked with -static is slightly bigger than a dynamically linked program but also slightly faster (3-5%). One problem, however, is that you can't use user-definable functions (UDFs) with a statically linked program. If you are going to write or use UDF functions (this is something only for C or C++ programmers), you must compile MySQL yourself, using dynamic linking.

If you are using a libc-based system (instead of a glibc2 system), you will probably get some problems with hostname resolving and getpwnam() with the binary release. (This is because glibc unfortunately depends on some external libraries to resolve hostnames and getpwent(), even when compiled with -static). In this case you probably get the following error message when you run mysql_install_db: 

Sorry, the host 'xxxx' could not be looked up

or the following error when you try to run mysqld with the --user option: 

getpwnam: No such file or directory

You can solve this problem in one of the following ways:

The Linux-Intel binary and RPM releases of MySQL are configured for the highest possible speed. We are always trying to use the fastest stable compiler available.

MySQL Perl support requires Version Perl 5.004_03 or newer.

On some Linux 2.2 versions, you may get the error Resource temporarily unavailable when you do a lot of new connections to a mysqld server over TCP/IP.

The problem is that Linux has a delay between when you close a TCP/IP socket and until this is actually freed by the system. As there is only room for a finite number of TCP/IP slots, you will get the above error if you try to do too many new TCP/IP connections during a small time, like when you run the MySQL `test-connect' benchmark over TCP/IP.

We have mailed about this problem a couple of times to different Linux mailing lists but have never been able to resolve this properly.

The only known 'fix' to this problem is to use persistent connections in your clients or use sockets, if you are running the database server and clients on the same machine. We hope that the Linux 2.4 kernel will fix this problem in the future.

4.6.3.2 HP-UX Notes for Binary Distributions

Some of the binary distributions of MySQL for HP-UX is distributed as an HP depot file and as a tar file. To use the depot file you must be running at least HP-UX 10.x to have access to HP's software depot tools.

The HP version of MySQL was compiled on an HP 9000/8xx server under HP-UX 10.20, and uses MIT-pthreads. It is known to work well under this configuration. MySQL Version 3.22.26 and newer can also be built with HP's native thread package.

Other configurations that may work:

The following configurations almost definitely won't work:

To install the distribution, use one of the commands below, where /path/to/depot is the full pathname of the depot file:

The depot places binaries and libraries in `/opt/mysql' and data in `/var/opt/mysql'. The depot also creates the appropriate entries in `/etc/init.d' and `/etc/rc2.d' to start the server automatically at boot time. Obviously, this entails being root to install.

To install the HP-UX tar.gz distribution, you must have a copy of GNU tar.

4.7 Installing a MySQL Source Distribution

Before you proceed with the source installation, check first to see if our binary is available for your platform and if it will work for you. We put in a lot of effort into making sure that our binaries are built with the best possible options.

You need the following tools to build and install MySQL from source:

If you are using a recent version of gcc, recent enough to understand -fno-exceptions option, it is VERY IMPORTANT that you use it. Otherwise, you may compile a binary that crashes randomly. We also recommend that you use -felide-contructors and -fno-rtti along with -fno-exceptions. When in doubt, do the following: 


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

On most systems this will give you a fast and stable binary.

If you run into problems, PLEASE ALWAYS USE mysqlbug when posting questions to mysql@lists.mysql.com. Even if the problem isn't a bug, mysqlbug gathers system information that will help others solve your problem. By not using mysqlbug, you lessen the likelihood of getting a solution to your problem! You will find mysqlbug in the `scripts' directory after you unpack the distribution. See section 2.3 How to Report Bugs or Problems.

4.7.1 Quick Installation Overview

The basic commands you must execute to install a MySQL source distribution are: 

shell> groupadd mysql
shell> useradd -g mysql mysql
shell> gunzip < mysql-VERSION.tar.gz | tar -xvf -
shell> cd mysql-VERSION
shell> ./configure --prefix=/usr/local/mysql
shell> make
shell> make install
shell> scripts/mysql_install_db
shell> chown -R root  /usr/local/mysql
shell> chown -R mysql /usr/local/mysql/var
shell> chgrp -R mysql /usr/local/mysql
shell> cp support-files/my-medium.cnf /etc/my.cnf
shell> /usr/local/mysql/bin/safe_mysqld --user=mysql &

If you want have support for InnoDB tables, you should edit the /etc/my.cnf file and remove the # character before the parameters that starts with innodb_.... See section 4.16.5 Option Files. See section 8.5.2 InnoDB startup options.

If you start from a source RPM, then do the following: 

shell> rpm --rebuild MySQL-VERSION.src.rpm

This will make a binary RPM that you can install.

You can add new users using the bin/mysql_setpermission script if you install the DBI and Msql-Mysql-modules Perl modules.

A more detailed description follows.

To install a source distribution, follow the steps below, then proceed to section 4.16 Post-installation Setup and Testing, for post-installation initialization and testing:

  1. Pick the directory under which you want to unpack the distribution, and move into it.
  2. Obtain a distribution file from one of the sites listed in section 4.1 How to Get MySQL.
  3. If you are interested in using Berkeley DB tables with MySQL, you will need to obtain a patched version of the Berkeley DB source code. Please read the chapter on Berkeley DB tables before proceeding. See section 8.6 BDB or Berkeley_DB Tables. MySQL source distributions are provided as compressed tar archives and have names like `mysql-VERSION.tar.gz', where VERSION is a number like 3.23.40.
  4. Add a user and group for mysqld to run as: 
    shell> groupadd mysql
shell> useradd -g mysql mysql
    These commands add the mysql group, and the mysql user. The syntax for useradd and groupadd may differ slightly on different versions of Unix. They may also be called adduser and addgroup. You may wish to call the user and group something else instead of mysql.
  5. Unpack the distribution into the current directory: 
    shell> gunzip < /path/to/mysql-VERSION.tar.gz | tar xvf -
    This command creates a directory named `mysql-VERSION'.
  6. Change into the top-level directory of the unpacked distribution: 
    shell> cd mysql-VERSION
    Note that currently you must configure and build MySQL from this top-level directory. You can not build it in a different directory.
  7. Configure the release and compile everything: 
    shell> ./configure --prefix=/usr/local/mysql
shell> make
    When you run configure, you might want to specify some options. Run ./configure --help for a list of options. section 4.7.3 Typical configure Options, discusses some of the more useful options. If configure fails, and you are going to send mail to mysql@lists.mysql.com to ask for assistance, please include any lines from `config.log' that you think can help solve the problem. Also include the last couple of lines of output from configure if configure aborts. Post the bug report using the mysqlbug script. See section 2.3 How to Report Bugs or Problems. If the compile fails, see section 4.9 Problems Compiling?, for help with a number of common problems.
  8. Install everything: 
    shell> make install
    You might need to run this command as root.
  9. Create the MySQL grant tables (necessary only if you haven't installed MySQL before): 
    shell> scripts/mysql_install_db
    Note that MySQL versions older than Version 3.22.10 started the MySQL server when you run mysql_install_db. This is no longer true!
  10. Change ownership of binaries to root and ownership of the data directory to the user that you will run mysqld as: 
    shell> chown -R root  /usr/local/mysql
shell> chown -R mysql /usr/local/mysql/var
shell> chgrp -R mysql /usr/local/mysql
    The first command changes the owner attribute of the files to the root user, the second one changes the owner attribute of the data directory to the mysql user, and the third one changes the group attribute to the mysql group.
  11. If you want to install support for the Perl DBI/DBD interface, see section 4.11 Perl Installation Comments.
  12. If you would like MySQL to start automatically when you boot your machine, you can copy support-files/mysql.server to the location where your system has its startup files. More information can be found in the support-files/mysql.server script itself and in section 4.16.3 Starting and Stopping MySQL Automatically.

After everything has been installed, you should initialize and test your distribution: 

shell> /usr/local/mysql/bin/safe_mysqld --user=mysql &

If that command fails immediately with mysqld daemon ended then you can find some information in the file `mysql-data-directory/'hostname'.err'. The likely reason is that you already have another mysqld server running. See section 22.3 Running Multiple MySQL Servers on the Same Machine.

See section 4.16 Post-installation Setup and Testing.

4.7.2 Applying Patches

Sometimes patches appear on the mailing list or are placed in the patches area of the MySQL Web site.

To apply a patch from the mailing list, save the message in which the patch appears in a file, change into the top-level directory of your MySQL source tree, and run these commands: 

shell> patch -p1 < patch-file-name
shell> rm config.cache
shell> make clean

Patches from the FTP site are distributed as plain text files or as files compressed with gzip. Apply a plain patch as shown above for mailing list patches. To apply a compressed patch, change into the top-level directory of your MySQL source tree and run these commands: 

shell> gunzip < patch-file-name.gz | patch -p1
shell> rm config.cache
shell> make clean

After applying a patch, follow the instructions for a normal source install, beginning with the ./configure step. After running the make install step, restart your MySQL server.

You may need to bring down any currently running server before you run make install. (Use mysqladmin shutdown to do this.) Some systems do not allow you to install a new version of a program if it replaces the version that is currently executing.

4.7.3 Typical configure Options

The configure script gives you a great deal of control over how you configure your MySQL distribution. Typically you do this using options on the configure command line. You can also affect configure using certain environment variables. See section A Environment Variables. For a list of options supported by configure, run this command: 

shell> ./configure --help

Some of the more commonly-used configure options are described below:

4.8 Installing from the Development Source Tree

CAUTION: You should read this section only if you are interested in helping us test our new code. If you just want to get MySQL up and running on your system, you should use a standard release distribution (either a source or binary distribution will do).

To obtain our most recent development source tree, use these instructions:

  1. Download BitKeeper from http://www.bitmover.com/cgi-bin/download.cgi. You will need Bitkeeper 2.0 or newer to access our repository.
  2. Follow the instructions to install it.
  3. After BitKeeper is installed, use this command if you want to clone the MySQL 3.23 branch: 
    shell> bk clone bk://work.mysql.com:7000 mysql
    To clone the 4.0 branch, use this command instead: 
    shell> bk clone bk://work.mysql.com:7001 mysql-4.0
    The initial download of the source tree may take a while, depending on the speed of your connection; be patient.
  4. You will need GNU autoconf, automake, libtool, and m4 to run the next set of commands. If you get some strange error during this stage, check that you really have libtool installed! 
    shell> cd mysql
shell> bk -r edit
shell> aclocal; autoheader; autoconf;  automake;
shell> ./configure  # Add your favorite options here
shell> make
    A collection of our standard configure scripts is located in the `BUILD/' subdirectory. If you are lazy, you can use `BUILD/compile-pentium-debug'. To compile on a different architecture, modify the script removing flags that are Pentium-specific.
  5. When the build is done, run make install. Be careful with this on a production machine; the command may overwrite your live release installation. If you have another installation of MySQL, we recommand that you run ./configure with different values for the prefix, tcp-port, and unix-socket-path options than those used for your production server.
  6. Play hard with your new installation and try to make the new features crash. Start by running make test. See section 26.2 MySQL Test Suite.
  7. If you have gotten to the make stage and the distribution does not compile, please report it to bugs@lists.mysql.com. If you have installed the latest versions of the required GNU tools, and they crash trying to process our configuration files, please report that also. However, if you execute aclocal and get a command not found error or a similar problem, do not report it. Instead, make sure all the necessary tools are installed and that your PATH variable is set correctly so your shell can find them.
  8. After the initial bk clone operation to get the source tree, you should run bk pull periodically to get the updates.
  9. You can examine the change history for the tree with all the diffs by using bk sccstool. If you see some funny diffs or code that you have a question about, do not hesitate to send e-mail to internals@lists.mysql.com. Also, if you think you have a better idea on how to do something, send an email to the same address with a patch. bk diffs will produce a patch for you after you have made changes to the source. If you do not have the time to code your idea, just send a description.
  10. BitKeeper has a nice help utility that you can access via bk helptool.

4.9 Problems Compiling?

All MySQL programs compile cleanly for us with no warnings on Solaris using gcc. On other systems, warnings may occur due to differences in system include files. See section 4.10 MIT-pthreads Notes for warnings that may occur when using MIT-pthreads. For other problems, check the list below.

The solution to many problems involves reconfiguring. If you do need to reconfigure, take note of the following:

To prevent old configuration information or object files from being used, run these commands before rerunning configure: 

shell> rm config.cache
shell> make clean

Alternatively, you can run make distclean.

The list below describes some of the problems compiling MySQL that have been found to occur most often:

4.10 MIT-pthreads Notes

This section describes some of the issues involved in using MIT-pthreads.

Note that on Linux you should NOT use MIT-pthreads but install LinuxThreads! See section 4.12.5 Linux Notes (All Linux Versions).

If your system does not provide native thread support, you will need to build MySQL using the MIT-pthreads package. This includes older FreeBSD systems, SunOS 4.x, Solaris 2.4 and earlier, and some others. See section 4.2 Operating Systems Supported by MySQL.

4.11 Perl Installation Comments

4.11.1 Installing Perl on Unix

Perl support for MySQL is provided by means of the DBI/DBD client interface. See section 24.2 MySQL Perl API. The Perl DBD/DBI client code requires Perl Version 5.004 or later. The interface will not work if you have an older version of Perl.

MySQL Perl support also requires that you've installed MySQL client programming support. If you installed MySQL from RPM files, client programs are in the client RPM, but client programming support is in the developer RPM. Make sure you've installed the latter RPM.

As of Version 3.22.8, Perl support is distributed separately from the main MySQL distribution. If you want to install Perl support, the files you will need can be obtained from http://www.mysql.com/Downloads/Contrib/.

The Perl distributions are provided as compressed tar archives and have names like `MODULE-VERSION.tar.gz', where MODULE is the module name and VERSION is the version number. You should get the Data-Dumper, DBI, and Msql-Mysql-modules distributions and install them in that order. The installation procedure is shown below. The example shown is for the Data-Dumper module, but the procedure is the same for all three distributions:

  1. Unpack the distribution into the current directory: 
    shell> gunzip < Data-Dumper-VERSION.tar.gz | tar xvf -
    This command creates a directory named `Data-Dumper-VERSION'.
  2. Change into the top-level directory of the unpacked distribution: 
    shell> cd Data-Dumper-VERSION
  3. Build the distribution and compile everything: 
    shell> perl Makefile.PL
shell> make
shell> make test
shell> make install

The make test command is important because it verifies that the module is working. Note that when you run that command during the Msql-Mysql-modules installation to exercise the interface code, the MySQL server must be running or the test will fail.

It is a good idea to rebuild and reinstall the Msql-Mysql-modules distribution whenever you install a new release of MySQL, particularly if you notice symptoms such as all your DBI scripts dumping core after you upgrade MySQL.

If you don't have the right to install Perl modules in the system directory or if you to install local Perl modules, the following reference may help you: 

http://www.iserver.com/support/contrib/perl5/modules.html

Look under the heading Installing New Modules that Require Locally Installed Modules.

4.11.2 Installing ActiveState Perl on Windows

To install the MySQL DBD module with ActiveState Perl on Windows, you should do the following:

The above should work at least with ActiveState Perl Version 5.6.

If you can't get the above to work, you should instead install the MyODBC driver and connect to MySQL server through ODBC: 

use DBI;
$dbh= DBI->connect("DBI:ODBC:$dsn","$user","$password") ||
  die "Got error $DBI::errstr when connecting to $dsn\n";

4.11.3 Installing the MySQL Perl Distribution on Windows

The MySQL Perl distribution contains DBI, DBD:MySQL and DBD:ODBC.

4.11.4 Problems Using the Perl DBI/DBD Interface

If Perl reports that it can't find the `../mysql/mysql.so' module, then the problem is probably that Perl can't locate the shared library `libmysqlclient.so'.

You can fix this by any of the following methods:

If you get the following errors from DBD-mysql, you are probably using gcc (or using an old binary compiled with gcc): 

/usr/bin/perl: can't resolve symbol '__moddi3'
/usr/bin/perl: can't resolve symbol '__divdi3'

Add -L/usr/lib/gcc-lib/... -lgcc to the link command when the `mysql.so' library gets built (check the output from make for `mysql.so' when you compile the Perl client). The -L option should specify the pathname of the directory where `libgcc.a' is located on your system.

Another cause of this problem may be that Perl and MySQL aren't both compiled with gcc. In this case, you can solve the mismatch by compiling both with gcc.

If you get the following error from Msql-Mysql-modules when you run the tests: 

t/00base............install_driver(mysql) failed: Can't load '../blib/arch/auto/DBD/mysql/mysql.so' for module DBD::mysql: ../blib/arch/auto/DBD/mysql/mysql.so: undefined symbol: uncompress at /usr/lib/perl5/5.00503/i586-linux/DynaLoader.pm line 169.

it means that you need to include the compression library, -lz, to the link line. This can be doing the following change in the file `lib/DBD/mysql/Install.pm': 

$sysliblist .= " -lm";

to

$sysliblist .= " -lm -lz";

After this, you MUST run 'make realclean' and then proceed with the installation from the beginning.

If you want to use the Perl module on a system that doesn't support dynamic linking (like SCO) you can generate a static version of Perl that includes DBI and DBD-mysql. The way this works is that you generate a version of Perl with the DBI code linked in and install it on top of your current Perl. Then you use that to build a version of Perl that additionally has the DBD code linked in, and install that.

On SCO, you must have the following environment variables set: 

shell> LD_LIBRARY_PATH=/lib:/usr/lib:/usr/local/lib:/usr/progressive/lib
or
shell> LD_LIBRARY_PATH=/usr/lib:/lib:/usr/local/lib:/usr/ccs/lib:/usr/progressive/lib:/usr/skunk/lib
shell> LIBPATH=/usr/lib:/lib:/usr/local/lib:/usr/ccs/lib:/usr/progressive/lib:/usr/skunk/lib
shell> MANPATH=scohelp:/usr/man:/usr/local1/man:/usr/local/man:/usr/skunk/man:

First, create a Perl that includes a statically linked DBI by running these commands in the directory where your DBI distribution is located: 

shell> perl Makefile.PL -static -config
shell> make
shell> make install
shell> make perl

Then you must install the new Perl. The output of make perl will indicate the exact make command you will need to execute to perform the installation. On SCO, this is make -f Makefile.aperl inst_perl MAP_TARGET=perl.

Next, use the just-created Perl to create another Perl that also includes a statically-linked DBD::mysql by running these commands in the directory where your Msql-Mysql-modules distribution is located: 

shell> perl Makefile.PL -static -config
shell> make
shell> make install
shell> make perl

Finally, you should install this new Perl. Again, the output of make perl indicates the command to use.

4.12 System-specific Issues

The following sections indicate some of the issues that have been observed to occur on particular systems when installing MySQL from a source distribution.

4.12.1 Solaris Notes

On Solaris, you may run into trouble even before you get the MySQL distribution unpacked! Solaris tar can't handle long file names, so you may see an error like this when you unpack MySQL: 

x mysql-3.22.12-beta/bench/Results/ATIS-mysql_odbc-NT_4.0-cmp-db2,informix,ms-sql,mysql,oracle,solid,sybase, 0 bytes, 0 tape blocks
tar: directory checksum error

In this case, you must use GNU tar (gtar) to unpack the distribution. You can find a precompiled copy for Solaris at http://www.mysql.com/Downloads/.

Sun native threads work only on Solaris 2.5 and higher. For Version 2.4 and earlier, MySQL will automatically use MIT-pthreads. See section 4.10 MIT-pthreads Notes.

If you get the following error from configure: 

checking for restartable system calls... configure: error can not run test
programs while cross compiling

This means that you have something wrong with your compiler installation! In this case you should upgrade your compiler to a newer version. You may also be able to solve this problem by inserting the following row into the `config.cache' file: 

ac_cv_sys_restartable_syscalls=${ac_cv_sys_restartable_syscalls='no'}

If you are using Solaris on a SPARC, the recommended compiler is gcc 2.95.2. You can find this at http://gcc.gnu.org/. Note that egcs 1.1.1 and gcc 2.8.1 don't work reliably on SPARC!

The recommended configure line when using gcc 2.95.2 is: 

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

If you have a ultra sparc, you can get 4 % more performance by adding "-mcpu=v8 -Wa,-xarch=v8plusa" to CFLAGS and CXXFLAGS.

If you have the Sun Workshop (SunPro) 4.2 (or newer) compiler, you can run configure like this: 

CC=cc CFLAGS="-Xa -fast -xO4 -native -xstrconst -mt" \
CXX=CC CXXFLAGS="-noex -xO4 -mt" \
./configure --prefix=/usr/local/mysql --enable-assembler

You may also have to edit the configure script to change this line: 

#if !defined(__STDC__) || __STDC__ != 1

to this: 

#if !defined(__STDC__)

If you turn on __STDC__ with the -Xc option, the Sun compiler can't compile with the Solaris `pthread.h' header file. This is a Sun bug (broken compiler or broken include file).

If mysqld issues the error message shown below when you run it, you have tried to compile MySQL with the Sun compiler without enabling the multi-thread option (-mt): 

libc internal error: _rmutex_unlock: rmutex not held

Add -mt to CFLAGS and CXXFLAGS and try again.

If you get the following error when compiling MySQL with gcc, it means that your gcc is not configured for your version of Solaris: 

shell> gcc -O3 -g -O2 -DDBUG_OFF  -o thr_alarm ...
./thr_alarm.c: In function `signal_hand':
./thr_alarm.c:556: too many arguments to function `sigwait'

The proper thing to do in this case is to get the newest version of gcc and compile it with your current gcc compiler! At least for Solaris 2.5, almost all binary versions of gcc have old, unusable include files that will break all programs that use threads (and possibly other programs)!

Solaris doesn't provide static versions of all system libraries (libpthreads and libdl), so you can't compile MySQL with --static. If you try to do so, you will get the error: 

ld: fatal: library -ldl: not found

or

undefined reference to `dlopen'

If too many processes try to connect very rapidly to mysqld, you will see this error in the MySQL log: 

Error in accept: Protocol error

You might try starting the server with the --set-variable back_log=50 option as a workaround for this. See section 4.16.4 mysqld Command-line Options.

If you are linking your own MySQL client, you might get the following error when you try to execute it: 

ld.so.1: ./my: fatal: libmysqlclient.so.#: open failed: No such file or directory

The problem can be avoided by one of the following methods:

When using the --with-libwrap configure option, you must also include the libraries that `libwrap.a' needs: 

--with-libwrap="/opt/NUtcpwrapper-7.6/lib/libwrap.a -lnsl -lsocket

If you have problems with configure trying to link with -lz and you don't have zlib installed, you have two options:

If you are using gcc and have problems with loading UDF functions into MySQL, try adding -lgcc to the link line for the UDF function.

If you would like MySQL to start automatically, you can copy `support-files/mysql.server' to `/etc/init.d' and create a symbolic link to it named `/etc/rc3.d/S99mysql.server'.

4.12.2 Solaris 2.7/2.8 Notes

You can normally use a Solaris 2.6 binary on Solaris 2.7 and 2.8. Most of the Solaris 2.6 issues also apply for Solaris 2.7 and 2.8.

Note that MySQL Version 3.23.4 and above should be able to autodetect new versions of Solaris and enable workarounds for the following problems!

Solaris 2.7 / 2.8 has some bugs in the include files. You may see the following error when you use gcc: 

/usr/include/widec.h:42: warning: `getwc' redefined
/usr/include/wchar.h:326: warning: this is the location of the previous
definition

If this occurs, you can do the following to fix the problem:

Copy /usr/include/widec.h to .../lib/gcc-lib/os/gcc-version/include and change line 41 from: 

#if     !defined(lint) && !defined(__lint)

to

#if     !defined(lint) && !defined(__lint) && !defined(getwc)

Alternatively, you can edit `/usr/include/widec.h' directly. Either way, after you make the fix, you should remove `config.cache' and run configure again!

If you get errors like this when you run make, it's because configure didn't detect the `curses.h' file (probably because of the error in `/usr/include/widec.h'): 

In file included from mysql.cc:50:
/usr/include/term.h:1060: syntax error before `,'
/usr/include/term.h:1081: syntax error before `;'

The solution to this is to do one of the following:

If you get a problem that your linker can't find -lz when linking your client program, the problem is probably that your `libz.so' file is installed in `/usr/local/lib'. You can fix this by one of the following methods:

4.12.3 Solaris x86 Notes

On Solaris 2.8 on x86, mysqld will core dump if you run 'strip' in.

If you are using gcc or egcs on Solaris x86 and you experience problems with core dumps under load, you should use the following configure command: 

CC=gcc CFLAGS="-O3 -fomit-frame-pointer -DHAVE_CURSES_H" \
CXX=gcc \
CXXFLAGS="-O3 -fomit-frame-pointer -felide-constructors -fno-exceptions -fno-rtti -DHAVE_CURSES_H" \
./configure --prefix=/usr/local/mysql

This will avoid problems with the libstdc++ library and with C++ exceptions.

If this doesn't help, you should compile a debug version and run it with a trace file or under gdb. See section I.1.3 Debugging mysqld under gdb.

4.12.4 SunOS 4 Notes

On SunOS 4, MIT-pthreads is needed to compile MySQL, which in turn means you will need GNU make.

Some SunOS 4 systems have problems with dynamic libraries and libtool. You can use the following configure line to avoid this problem: 

shell> ./configure --disable-shared --with-mysqld-ldflags=-all-static

When compiling readline, you may get warnings about duplicate defines. These may be ignored.

When compiling mysqld, there will be some implicit declaration of function warnings. These may be ignored.

4.12.5 Linux Notes (All Linux Versions)

The notes below regarding glibc apply only to the situation when you build MySQL yourself. If you are running Linux on an x86 machine, in most cases it is much better for you to just use our binary. We link our binaries against the best patched version of glibc we can come up with and with the best compiler options, in an attempt to make it suitable for a high-load server. So if you read the text below, and are in doubt about what you should do, try our binary first to see if it meets your needs, and worry about your own build only after you have discovered that our binary is not good enough. In that case, we would appreciate a note about it, so we can build a better binary next time. For a typical user, even for setups with a lot of concurrent connections and/or tables exceeding 2GB limit, our binary in most cases is the best choice.

MySQL uses LinuxThreads on Linux. If you are using an old Linux version that doesn't have glibc2, you must install LinuxThreads before trying to compile MySQL. You can get LinuxThreads at http://www.mysql.com/Downloads/Linux.

NOTE: We have seen some strange problems with Linux 2.2.14 and MySQL on SMP systems; If you have a SMP system, we recommend you to upgrade to Linux 2.4 ASAP! Your system will be faster and more stable by doing this!

Note that glibc versions before and including Version 2.1.1 have a fatal bug in pthread_mutex_timedwait handling, which is used when you do INSERT DELAYED. We recommend you to not use INSERT DELAYED before upgrading glibc.

If you plan to have 1000+ concurrent connections, you will need to make some changes to LinuxThreads, recompile it, and relink MySQL against the new `libpthread.a'. Increase PTHREAD_THREADS_MAX in `sysdeps/unix/sysv/linux/bits/local_lim.h' to 4096 and decrease STACK_SIZE in `linuxthreads/internals.h' to 256 KB. The paths are relative to the root of glibc Note that MySQL will not be stable with around 600-1000 connections if STACK_SIZE is the default of 2 MB.

If you have a problem with that MySQL can't open enough files, or connections, it may be that you haven't configured Linux to handle enough files.

In Linux 2.2 and forwards, you can check the number of allocated file handlers by doing: 

cat /proc/sys/fs/file-max
cat /proc/sys/fs/dquot-max 
cat /proc/sys/fs/super-max

If you have more than 16M of memory, you should add something like the following in your boot script (`/etc/rc/boot.local' on SuSE): 

echo 65536 > /proc/sys/fs/file-max
echo 8192 > /proc/sys/fs/dquot-max
echo 1024 > /proc/sys/fs/super-max

You can also run the above from the command line as root, but in this case your old limits will be used next time your computer reboots.

You should also add /etc/my.cnf: 

[safe_mysqld]
open_files_limit=8192

The above should allow MySQL to create up to 8192 connections/files.

The STACK_SIZE constant in LinuxThreads controls the spacing of thread stacks in the address space. It needs to be large enough so that there will be plenty of room for the stack of each individual thread, but small enough to keep the stack of some thread from running into the global mysqld data. Unfortunately, the Linux implementation of mmap(), as we have experimentally discovered, will successfully unmap an already mapped region if you ask it to map out an address already in use, zeroing out the data on the entire page, instead of returning an error. So, the safety of mysqld or any other threaded application depends on the "gentleman" behavior of the code that creates threads. The user must take measures to make sure the number of running threads at any time is sufficiently low for thread stacks to stay away from the global heap. With mysqld, you should enforce this "gentleman" behavior by setting a reasonable value for the max_connections variable.

If you build MySQL yourself and do not what to mess with patching LinuxThreads, you should set max_connections to a value no higher than 500. It should be even less if you have a large key buffer, large heap tables, or some other things that make mysqld allocate a lot of memory or if you are running a 2.2 kernel with a 2GB patch. If you are using our binary or RPM version 3.23.25 or later, you can safely set max_connections at 1500, assuming no large key buffer or heap tables with lots of data. The more you reduce STACK_SIZE in LinuxThreads the more threads you can safely create. We recommend the values between 128K and 256K.

If you use a lot of concurrent connections, you may suffer from a "feature" in the 2.2 kernel that penalizes a process for forking or cloning a child in an attempt to prevent a fork bomb attack. This will cause MySQL not to scale well as you increase the number of concurrent clients. On single CPU systems, we have seen this manifested in a very slow thread creation, which means it may take a long time to connect to MySQL (as long as 1 minute), and it may take just as long to shut it down. On multiple CPU systems, we have observed a gradual drop in query speed as the number of clients increases. In the process of trying to find a solution, we have received a kernel patch from one of our users, who claimed it made a lot of difference for his site. The patch is available here (http://www.mysql.com/Downloads/Patches/linux-fork.patch). We have now done rather extensive testing of this patch on both development and production systems. It has significantly improved MySQL performance without causing any problems and we now recommend it to our users who are still running high-load servers on 2.2 kernels. This issue has been fixed in the 2.4 kernel, so if you are not satisfied with the current performance of your system, rather than patching your 2.2 kernel, it might be easier to just upgrade to 2.4, which will also give you a nice SMP boost in addition to fixing this fairness bug.

We have tested MySQL on the 2.4 kernel on a 2 CPU machine and found MySQL scales MUCH better - there was virtually no slowdown on query throughput all the way up to 1000 clients, and MySQL scaling factor ( computed as the ratio of maximum throughput to the throughput with one client) was 180%. We have observed similar results on a 4-CPU system - virtually no slowdown as the number of clients was increased up to 1000, and 300% scaling factor. So for a high-load SMP server we would definitely recommend the 2.4 kernel at this point. We have discovered that it is essential to run mysqld process with the highest possible priority on the 2.4 kernel to achieve maximum performance. This can be done by adding renice -20 $$ command to safe_mysqld. In our testing on a 4-CPU machine, increasing the priority gave 60% increase in throughput with 400 clients.

We are currently also trying to collect more info on how well MySQL performs on 2.4 kernel on 4-way and 8-way systems. If you have access such a system and have done some benchmarks, please send a mail to docs@mysql.com with the results - we will include them in the manual.

There is another issue that greatly hurts MySQL performance, especially on SMP systems. The implementation of mutex in LinuxThreads in glibc-2.1 is very bad for programs with many threads that only hold the mutex for a short time. On an SMP system, ironic as it is, if you link MySQL against unmodified LinuxThreads, removing processors from the machine improves MySQL performance in many cases. We have made a patch available for glibc 2.1.3, linuxthreads-2.1-patch to correct this behavior.

With glibc-2.2.2 MySQL version 3.23.36 will use the adaptive mutex, which is much better than even the patched one in glibc-2.1.3. Be warned, however, that under some conditions, the current mutex code in glibc-2.2.2 overspins, which hurts MySQL performance. The chance of this condition can be reduced by renicing mysqld process to the highest priority. We have also been able to correct the overspin behavior with a patch, available here. It combines the correction of overspin, maximum number of threads, and stack spacing all in one. You will need to apply it in the linuxthreads directory with patch -p0 </tmp/linuxthreads-2.2.2.patch. We hope it will be included in some form in to the future releases of glibc-2.2. In any case, if you link against glibc-2.2.2 you still need to correct STACK_SIZE and PTHREAD_THREADS_MAX. We hope that the defaults will be corrected to some more acceptable values for high-load MySQL setup in the future, so that your own build can be reduced to ./configure; make; make install.

We recommend that you use the above patches to build a special static version of libpthread.a and use it only for statically linking against MySQL. We know that the patches are safe for MySQL and significantly improve its performance, but we cannot say anything about other applications. If you link other applications against the patched version of the library, or build a patched shared version and install it on your system, you are doing it at your own risk with regard to other applications that depend on LinuxThreads.

If you experience any strange problems during the installation of MySQL, or with some common utilties hanging, it is very likely that they are either library or compiler related. If this is the case, using our binary will resolve them.

One known problem with the binary distribution is that with older Linux systems that use libc (like RedHat 4.x or Slackware), you will get some non-fatal problems with hostname resolution. See section 4.6.3.1 Linux Notes for Binary Distributions.

When using LinuxThreads you will see a minimum of three processes running. These are in fact threads. There will be one thread for the LinuxThreads manager, one thread to handle connections, and one thread to handle alarms and signals.

Note that the Linux kernel and the LinuxThread library can by default only have 1024 threads. This means that you can only have up to 1021 connections to MySQL on an unpatched system. The page http://www.volano.com/linuxnotes.html contains information how to go around this limit.

If you see a dead mysqld daemon process with ps, this usually means that you have found a bug in MySQL or you have a corrupted table. See section 21.2 What to Do if MySQL Keeps Crashing.

To get a core dump on Linux if mysqld dies with a SIGSEGV signal, you can start mysqld with the --core-file option. Note that you also probably need to raise the core file size by adding ulimit -c 1000000 to safe_mysqld or starting safe_mysqld with --core-file-sizes=1000000. See section 15.3 safe_mysqld, the wrapper around mysqld.

To get a core dump on Linux if mysqld dies with a SIGSEGV signal, you can start mysqld with the --core-file option. Note that you also probably need to raise the core file size by adding ulimit -c 1000000 to safe_mysqld or starting safe_mysqld with --core-file-sizes=1000000. See section 15.3 safe_mysqld, the wrapper around mysqld.

If you are linking your own MySQL client and get the error: 

ld.so.1: ./my: fatal: libmysqlclient.so.4: open failed: No such file or directory

When executing them, the problem can be avoided by one of the following methods:

If you are using the Fujitsu compiler (fcc / FCC) you will have some problems compiling MySQL because the Linux header files are very gcc oriented.

The following configure line should work with fcc/FCC: 

CC=fcc CFLAGS="-O -K fast -K lib -K omitfp -Kpreex -D_GNU_SOURCE -DCONST=const -DNO_STRTOLL_PROTO" CXX=FCC CXXFLAGS="-O -K fast -K lib  -K omitfp -K preex --no_exceptions --no_rtti -D_GNU_SOURCE -DCONST=const -Dalloca=__builtin_alloca -DNO_STRTOLL_PROTO '-D_EXTERN_INLINE=static __inline'" ./configure --prefix=/usr/local/mysql --enable-assembler --with-mysqld-ldflags=-all-static --disable-shared --with-low-memory

4.12.5.1 Linux-x86 Notes

MySQL requires libc Version 5.4.12 or newer. It's known to work with libc 5.4.46. glibc Version 2.0.6 and later should also work. There have been some problems with the glibc RPMs from RedHat, so if you have problems, check whether or not there are any updates! The glibc 2.0.7-19 and 2.0.7-29 RPMs are known to work.

On some older Linux distributions, configure may produce an error like this: 

Syntax error in sched.h. Change _P to __P in the /usr/include/sched.h file.
See the Installation chapter in the Reference Manual.

Just do what the error message says and add an extra underscore to the _P macro that has only one underscore, then try again.

You may get some warnings when compiling; those shown below can be ignored: 

mysqld.cc -o objs-thread/mysqld.o
mysqld.cc: In function `void init_signals()':
mysqld.cc:315: warning: assignment of negative value `-1' to `long unsigned int'
mysqld.cc: In function `void * signal_hand(void *)':
mysqld.cc:346: warning: assignment of negative value `-1' to `long unsigned int'

In Debian GNU/Linux, if you want MySQL to start automatically when the system boots, do the following: 

shell> cp support-files/mysql.server /etc/init.d/mysql.server
shell> /usr/sbin/update-rc.d mysql.server defaults 99

mysql.server can be found in the `share/mysql' directory under the MySQL installation directory or in the `support-files' directory of the MySQL source tree.

If mysqld always core dumps when it starts up, the problem may be that you have an old `/lib/libc.a'. Try renaming it, then remove `sql/mysqld' and do a new make install and try again. This problem has been reported on some Slackware installations. RedHat Version 5.0 also has a similar problem with some new glibc versions. See section 4.12.5.2 RedHat Version 5.0 Notes.

If you get the following error when linking mysqld, it means that your `libg++.a' is not installed correctly: 

/usr/lib/libc.a(putc.o): In function `_IO_putc':
putc.o(.text+0x0): multiple definition of `_IO_putc'

You can avoid using `libg++.a' by running configure like this: 

shell> CXX=gcc ./configure

4.12.5.2 RedHat Version 5.0 Notes

If you have any problems with MySQL on RedHat, you should start by upgrading glibc to the newest possible version!

If you install all the official RedHat patches (including glibc-2.0.7-19 and glibc-devel-2.0.7-19), both the binary and source distributions of MySQL should work without any trouble!

The updates are needed because there is a bug in glibc 2.0.5 in how pthread_key_create variables are freed. With glibc 2.0.5, you must use a statically linked MySQL binary distribution. If you want to compile from source, you must install the corrected version of LinuxThreads from http://www.mysql.com/Downloads/Linux or upgrade your glibc.

If you have an incorrect version of glibc or LinuxThreads, the symptom is that mysqld crashes after each connection. For example, mysqladmin version will crash mysqld when it finishes!

Another symptom of incorrect libraries is that mysqld crashes at once when it starts. On some Linux systems, this can be fixed by configuring like this: 

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

On Redhat Version 5.0, the easy way out is to install the glibc 2.0.7-19 RPM and run configure without the --with-mysqld-ldflags=-all-static option.

For the source distribution of glibc 2.0.7, a patch that is easy to apply and is tested with MySQL may be found at: 

http://www.mysql.com/Downloads/Linux/glibc-2.0.7-total-patch.tar.gz

If you experience crashes like these when you build MySQL, you can always download the newest binary version of MySQL. This is statically-linked to avoid library conflicts and should work on all Linux systems!

MySQL comes with an internal debugger that can generate trace files with a lot of information that can be used to find and solve a wide range of different problems. See section I.1 Debugging a MySQL server.

4.12.5.3 RedHat Version 5.1 notes

The glibc of RedHat Version 5.1 (glibc 2.0.7-13) has a memory leak, so to get a stable MySQL version, you must upgrade glibc, to 2.0.7-19, downgrade glibc or use a binary version of mysqld. If you don't do this, you will encounter memory problems (out of memory, etc.). The most common error in this case is: 

Can't create a new thread (errno 11). If you are not out of available
memory, you can consult the manual for any possible OS dependent bug

After you have upgraded to glibc 2.0.7-19, you can configure MySQL with dynamic linking (the default), but you cannot run configure with the --with-mysqld-ldflags=-all-static option until you have installed glibc 2.0.7-19 from source!

You can check which version of glibc you have with rpm -q glibc.

Another reason for the above error is if you try to use more threads than your Linux kernel is configured for. In this case you should raise the limits in `include/linux/tasks.h' and recompile your kernel!

4.12.5.4 Linux-SPARC Notes

In some implementations, readdir_r() is broken. The symptom is that SHOW DATABASES always returns an empty set. This can be fixed by removing HAVE_READDIR_R from `config.h' after configuring and before compiling.

Some problems will require patching your Linux installation. The patch can be found at http://www.mysql.com/Downloads/patches/Linux-sparc-2.0.30.diff. This patch is against the Linux distribut