Installation Related Issues
===========================

Problems When Linking with the MySQL Client Library
---------------------------------------------------

If you are linking your program and you get errors for unreferenced
symbols that start with `mysql_', like the following:

      undefined reference to `mysql_real_connect'
     /tmp/ccFKsdPa.o(.text+0x69): undefined reference to `mysql_error'
     /tmp/ccFKsdPa.o(.text+0x9a): undefined reference to `mysql_close'

you should be able to solve this by adding `-Lpath-to-the-mysql-library
-lmysqlclient' *last* on your link line.

If you get `undefined reference' errors for the `uncompress' or
`compress' function, add `-lz' *last* on your link line and try again!

If you get `undefined reference' errors for functions that should exist
on your system, like `connect', check the man page for the function in
question, for which libraries you should add to the link line!

If you get `undefined reference' errors for functions that don't exist
on your system, like the following:

     mf_format.o(.text+0x201): undefined reference to `__lxstat'

it usually means that your library is compiled on a system that is not
100% compatible with yours.  In this case you should download the
latest MySQL source distribution and compile this yourself.  *Note
Installing source::.

If you are trying to run a program and you then get errors for
unreferenced symbols that start with `mysql_' or that the `mysqlclient'
library can't be found, this means that your system can't find the
share `libmysqlclient.so' library.

The fix for this is to tell your system to search after shared
libraries where the library is located by one of the following methods:

   * Add the path to the directory where you have `libmysqlclient.so'
     the `LD_LIBRARY_PATH' environment variable.

   * Add the path to the directory where you have `libmysqlclient.so'
     the `LD_LIBRARY' environment variable.

   * Copy `libmysqlclient.so' to some place that is searched by your
     system, like `/lib', and update the shared library information by
     executing `ldconfig'.

 other
programs are using the dynamic libraries!

How to Run MySQL As a Normal User
---------------------------------

The MySQL server `mysqld' can be started and run by any user.  In order
to change `mysqld' to run as a Unix user `user_name', you must do the
following:

  1. Stop the server if it's running (use `mysqladmin shutdown').

  2. Change the database directories and files so that `user_name' has
     privileges to read and write files in them (you may need to do
     this as the Unix `root' user):

          shell> chown -R user_name /path/to/mysql/datadir

     
     symlinks for you.

  3. Start the server as user `user_name', or, if you are using MySQL
     Version 3.22 or later, start `mysqld' as the Unix `root' user and
     use the `--user=user_name' option.  `mysqld' will switch to run as
     the Unix user `user_name' before accepting any connections.

  4. To start the server as the given user name automatically at system
     startup time, add a `user' line that specifies the user name to
     the `[mysqld]' group of the `/etc/my.cnf' option file or the
     `my.cnf' option file in the server's data directory. For example:

          [mysqld]
          user=user_name

At this point, your `mysqld' process should be running fine and dandy as
the Unix user `user_name'. One thing hasn't changed, though: the
contents of the permissions tables. By default (right after running the
permissions table install script `mysql_install_db'), the MySQL user
`root' is the only user with permission to access the `mysql' database
or to create or drop databases.  Unless you have changed those
permissions, they still hold. This shouldn't stop you from accessing
MySQL as the MySQL `root' user when you're logged in as a Unix user
other than `root'; just specify the `-u root' option to the client
program.

Note that accessing MySQL as `root', by supplying `-u root' on the
command-line, has *nothing* to do with MySQL running as the Unix `root'
user, or, indeed, as another Unix user. The access permissions and user
names of MySQL are completely separate from Unix user names. The only
connection with Unix user names is that if you don't provide a `-u'
option when you invoke a client program, the client will try to connect
using your Unix login name as your MySQL user name.

If your Unix box itself isn't secured, you should probably at least put
a password on the MySQL `root' users in the access tables.  Otherwise,
any user with an account on that machine can run `mysql -u root
db_name' and do whatever he likes.

Problems with File Permissions
------------------------------

If you have problems with file permissions, for example, if `mysql'
issues the following error message when you create a table:

     ERROR: Can't find file: 'path/with/filename.frm' (Errcode: 13)

  shell> UMASK=384  # = 600 in octal
     shell> export UMASK
     shell> /path/to/mysqld_safe &

By default MySQL will create database and `RAID' directories with
permission type 0700.  You can modify this behaviour by setting the
`UMASK_DIR' variable. If you set this, new directories are created with
the combined `UMASK' and `UMASK_DIR'. For example, if you want to give
group access to all new directories, you can do:

     shell> UMASK_DIR=504  # = 770 in octal
     shell> export UMASK_DIR
     shell> /path/to/mysqld_safe &

In MySQL Version 3.23.25 and above, MySQL assumes that the value for
`UMASK' and `UMASK_DIR' is in octal if it starts with a zero.

*Note Environment variables::.

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