Start by searching the MySQL online manual at http://dev.mysql.com/doc/. We try to keep the manual up to date by updating it frequently with solutions to newly found problems. The change history (http://dev.mysql.com/doc/mysql/en/news.html) can be particularly useful since it is quite possible that a newer version contains a solution to your problem.

If you get a parse error for a SQL statement, please check your syntax closely. If you can't find something wrong with it, it's extremely likely that your current version of MySQL Server doesn't support the syntax you are using. If you are using the current version and the manual doesn't cover the syntax that you are using, MySQL Server doesn't support your statement. In this case, your options are to implement the syntax yourself or email <licensing@mysql.com> and ask for an offer to implement it.

If the manual covers the syntax you are using, but you have an older version of MySQL Server, you should check the MySQL change history to see when the syntax was implemented. In this case, you have the option of upgrading to a newer version of MySQL Server.

For solutions to some common problems, see Section B.1, “Problems and Common Errors”.

Search the bugs database at http://bugs.mysql.com/ to see whether the bug has been reported and fixed.

Search the MySQL mailing list archives at http://lists.mysql.com/. See Section 1.7.1, “MySQL Mailing Lists”.

You can also use http://www.mysql.com/search/ to search all the Web pages (including the manual) that are located at the MySQL AB Web site.

The version number of the MySQL distribution you are using (for example, MySQL 5.0.19). You can find out which version you are running by executing mysqladmin version. The mysqladmin program can be found in the bin directory under your MySQL installation directory.

The manufacturer and model of the machine on which you experience the problem.

The operating system name and version. If you work with Windows, you can usually get the name and version number by double-clicking your My Computer icon and pulling down the “Help/About Windows” menu. For most Unix-like operating systems, you can get this information by executing the command uname -a.

Sometimes the amount of memory (real and virtual) is relevant. If in doubt, include these values.

If you are using a source distribution of the MySQL software, include the name and version number of the compiler that you used. If you have a binary distribution, include the distribution name.

If the problem occurs during compilation, include the exact error messages and also a few lines of context around the offending code in the file where the error occurs.

If mysqld died, you should also report the statement that crashed mysqld. You can usually get this information by running mysqld with query logging enabled, and then looking in the log after mysqld crashes. See MySQL Internals: Porting.

If a database table is related to the problem, include the output from the SHOW CREATE TABLE db_name.tbl_name statement in the bug report. This is a very easy way to get the definition of any table in a database. The information helps us create a situation matching the one that you have experienced.

The SQL mode in effect when the problem occurred can be significant, so please report the value of the sql_mode system variable. For stored procedure, stored function, and trigger objects, the relevant sql_mode value is the one in effect when the object was created. For a stored procedure or function, the SHOW CREATE PROCEDURE or SHOW CREATE FUNCTION statement shows the relevant SQL mode, or you can query INFORMATION_SCHEMA for the information:

SELECT ROUTINE_SCHEMA, ROUTINE_NAME, SQL_MODE
FROM INFORMATION_SCHEMA.ROUTINES;

For triggers, you can use this statement:

SELECT EVENT_OBJECT_SCHEMA, EVENT_OBJECT_TABLE, TRIGGER_NAME, SQL_MODE
FROM INFORMATION_SCHEMA.TRIGGERS;

For performance-related bugs or problems with SELECT statements, you should always include the output of EXPLAIN SELECT ..., and at least the number of rows that the SELECT statement produces. You should also include the output from SHOW CREATE TABLE tbl_name for each table that is involved. The more information you provide about your situation, the more likely it is that someone can help you.

The following is an example of a very good bug report. The statements are run using the mysql command-line tool. Note the use of the \G statement terminator for statements that would otherwise provide very long output lines that are difficult to read.

mysql> SHOW VARIABLES;
mysql> SHOW COLUMNS FROM ...\G
       <output from SHOW COLUMNS>
mysql> EXPLAIN SELECT ...\G
       <output from EXPLAIN>
mysql> FLUSH STATUS;
mysql> SELECT ...;
       <A short version of the output from SELECT,
       including the time taken to run the query>
mysql> SHOW STATUS;
       <output from SHOW STATUS>

If a bug or problem occurs while running mysqld, try to provide an input script that reproduces the anomaly. This script should include any necessary source files. The more closely the script can reproduce your situation, the better. If you can make a reproducible test case, you should upload it to be attached to the bug report.

If you can't provide a script, you should at least include the output from mysqladmin variables extended-status processlist in your report to provide some information on how your system is performing.

If you can't produce a test case with only a few rows, or if the test table is too big to be included in the bug report (more than 10 rows), you should dump your tables using mysqldump and create a README file that describes your problem. Create a compressed archive of your files using tar and gzip or zip, and use FTP to transfer the archive to ftp://ftp.mysql.com/pub/mysql/upload/. Then enter the problem into our bugs database at http://bugs.mysql.com/.

If you believe that the MySQL server produces a strange result from a statement, include not only the result, but also your opinion of what the result should be, and an explanation describing the basis for your opinion.

When you provide an example of the problem, it's better to use the table names, variable names, and so forth that exist in your actual situation than to come up with new names. The problem could be related to the name of a table or variable. These cases are rare, perhaps, but it is better to be safe than sorry. After all, it should be easier for you to provide an example that uses your actual situation, and it is by all means better for us. If you have data that you don't want to be visible to others in the bug report, you can use FTP to transfer it to ftp://ftp.mysql.com/pub/mysql/upload/. If the information is really top secret and you don't want to show it even to us, go ahead and provide an example using other names, but please regard this as the last choice.

Include all the options given to the relevant programs, if possible. For example, indicate the options that you use when you start the mysqld server, as well as the options that you use to run any MySQL client programs. The options to programs such as mysqld and mysql, and to the configure script, are often key to resolving problems and are very relevant. It is never a bad idea to include them. If your problem involves a program written in a language such as Perl or PHP, please include the language processor's version number, as well as the version for any modules that the program uses. For example, if you have a Perl script that uses the DBI and DBD::mysql modules, include the version numbers for Perl, DBI, and DBD::mysql.

If your question is related to the privilege system, please include the output of mysqlaccess, the output of mysqladmin reload, and all the error messages you get when trying to connect. When you test your privileges, you should first run mysqlaccess. After this, execute mysqladmin reload version and try to connect with the program that gives you trouble. mysqlaccess can be found in the bin directory under your MySQL installation directory.

If you have a patch for a bug, do include it. But don't assume that the patch is all we need, or that we can use it, if you don't provide some necessary information such as test cases showing the bug that your patch fixes. We might find problems with your patch or we might not understand it at all. If so, we can't use it.

If we can't verify the exact purpose of the patch, we won't use it. Test cases help us here. Show that the patch handles all the situations that may occur. If we find a borderline case (even a rare one) where the patch won't work, it may be useless.

Guesses about what the bug is, why it occurs, or what it depends on are usually wrong. Even the MySQL team can't guess such things without first using a debugger to determine the real cause of a bug.

Indicate in your bug report that you have checked the reference manual and mail archive so that others know you have tried to solve the problem yourself.

If the problem is that your data appears corrupt or you get errors when you access a particular table, you should first check your tables and then try to repair them with CHECK TABLE and REPAIR TABLE or with myisamchk. See Chapter 5, Database Administration.

If you are running Windows, please verify the value of lower_case_table_names using the SHOW VARIABLES LIKE 'lower_case_table_names' command. This variable affects how the server handles lettercase of database and table names. Its effect for a given value should be as described in Section 9.2.2, “Identifier Case Sensitivity”.

If you often get corrupted tables, you should try to find out when and why this happens. In this case, the error log in the MySQL data directory may contain some information about what happened. (This is the file with the .err suffix in the name.) See Section 5.11.1, “The Error Log”. Please include any relevant information from this file in your bug report. Normally mysqld should never crash a table if nothing killed it in the middle of an update. If you can find the cause of mysqld dying, it's much easier for us to provide you with a fix for the problem. See Section B.1.1, “How to Determine What Is Causing a Problem”.

If possible, download and install the most recent version of MySQL Server and check whether it solves your problem. All versions of the MySQL software are thoroughly tested and should work without problems. We believe in making everything as backward-compatible as possible, and you should be able to switch MySQL versions without difficulty. See Section 2.4.3, “Choosing Which MySQL Distribution to Install”.