MySQL Reference Manual for version 3.22.14b-gamma.

2 MySQL mailing lists and how to ask questions or report errors (bugs)

2.1 The MySQL mailing lists

Requests to be added to or dropped from the main MySQL mailing list should be sent to the electronic mail address mdomo@tcx.se. Sending a one-line message saying either subscribe mysql or unsubscribe mysql suffices. If your reply address is not valid, you may specify your address explicitly using subscribe mysql your-name@your.domain or unsubscribe mysql your-name@your.domain.

Please do not send mail about subscribing or unsubscribing to forwarded automatically to hundreds of other users.

Your local site may have many subscribers to mysql@tcx.se. If so, it may have a local mailing list, so that a single message from tcx.se is sent to the site and propagated to the local list. In such cases, please contact your system administrator to be added to or dropped from the local MySQL list.

Mail to mdomo@tcx.se is handled automatically by the Majordomo mailing list processor.

The following MySQL mailing lists exist:

mysql-announce

This is for announcement of new versions of MySQL and related programs. This is a low volume list that we think all MySQL users should be on.

mysql

The main list for general MySQL discussion. Please note that some things should go to the more-specialized lists. It you post to the wrong list, you may not get an answer!

mysql-digest

The mysql list in digest form. That means you get all individual messages, sent as one large mail message once a day.

mysql-Java

Discussion about MySQL and Java. Mostly about the JDBC drivers.

mysql-win32

All things concerning MySQL on Microsoft operating systems like Windows/NT.

myodbc

All things concerning connecting to MySQL with ODBC.

msql-mysql-modules

A list about the Perl support in MySQL.

msql-mysql-modules-digest

A digest version of the msql-mysql-modules list.

mysql-developer

A list for people who work on the MySQL code.

You subscribe or unsubscribe to all lists in the same way as described above. In your subscribe or unsubscribe request, just put the appropriate mailing list name rather than mysql.

2.2 Asking questions or reporting bugs

Before you ask a question on the mailing list, it is a good idea to check this manual. If you can't find an answer here, check with your local MySQL expert. If you still can't find an answer to your question, go ahead and read the next section about how to send mail to

2.3 How to report bugs / problems

Before posting a bug report / question, please start by searching the MySQL online manual http://www.mysql.com/Manual_chapter/index.html and in the MySQL mail archives. We try to keep the manual up to date and we constantly update this with solutions to new found problems! You can find the some search able mail archives at http://www.mysql.com/doc.html. You can also use http://www.mysql.com/search.html to search all the web pages (including the manual) at http://www.mysql.com.

Writing a good bug report takes patience, but doing it right at once saves time from us and from you. This section will help you writing your report right and prevents consuming your time doing things that may not help us much or at all.

We encourage everyone to use script mysqlbug to generate a bug report, or a report about any problem, if possible. The mysqlbug can be found from the `scripts' in the distribution or in the `bin' directory, where you have installed MySQL. If you are unable to use it, you should still include all the necessary information from this section.

The mysqlbug will help you making the report by automatically finding a lot of the following information, but if something important is missing, please include it with your message! Please read carefully this section and make sure you have all the information described here included in your report.

Remember that it is possible to answer a letter with too much information, but not the one with too little. Often people omit facts, because they think they know what is the reason for the problem and assume that some details don't matter. A good principle is: if you are in doubt to state something, state it! It is a thousand times faster and less troublesome to read a couple of lines more than to be forced to ask again and wait for the answer.

Most common errors are that people don't tell the MySQL version number they are using, or don't tell on what platform they have MySQL installed on, including the version number of the platform. This is very relevant information and in 99 cases out of 100 the bug report is useless without this information! Very often we get questions like 'Why doesn't this work for me?' and then we found that the quested feature wasn't yet implemented to that MySQL version, or there was a bug which was already fixed in the newer MySQL versions. Sometimes the error is platform depended and it is next to impossible to fix anything without knowing the operating system and the version number of the platform.

Remember also to give information about your compiler, if it is related to the problem. Often people found bugs in compilers and think the problem is MySQL related. Most compilers are under development all the time and become better version by version too. To verify, if the problem depends on compiler, we need to know what compiler is used. Note that every compiling problem should be regarded as a bug report and reported according to it.

Most helpful is when a good description of the problem is given. That is, a good example of all the things one did that leaded to the problem and the problem itself exactly described. The best bug reports are those that includes a full example how to reproduce the bug or problem.

If a program gives an error message, please include it. If we try to search something from the archives using programs, it is better that the error message is exactly the one that the program gave. (Even the case sensitivity should be observed!) This is the reason why >>cut'n'paste>> is the only right principle here!

• Version number of the MySQL you are using (for example, MySQL 3.22.12). You can find out which version you are running by executing mysqladmin version. mysqladmin can be found from the `bin' directory where MySQL is installed.
• The manufacturer and model of the machine you are working on.
• The operating system name and version. For most operating systems, you can get this by executing a Unix command uname -a.
• Sometimes the amount of memory is relevant. (real and virtual) If in doubt, include them.
• If one has the source distribution of MySQL, the information about the compiler used is needed. The name and the version number. If one has a binary distribution, the distribution name is needed.
• If the problem occurs during a compilation, include the exact error message(s) and also a few lines around the offending code in the file where the error occurred.
• Include the output from mysqldump --no-data database table1 table2..., if any table is related to the problem. This is very easy and a powerful way to get information about any table in a database and we will be able to create a situation that matches the one you have.
• In speed related bugs/problems with selects, one should always include the output of 'explain select ...' and at least the number of rows that the 'select ...' gives.
• If a problem / bug occurs while running MySQL, an input script, which will reproduce the bug, is needed. This script should include all the necessary source files, if any. The closer to the real situation the script will make, the better.
• If you think that MySQL gives a strange result from a query, include not only the result, but also your opinion what the result should be and some account for why.
• When giving an example of the problem, it's better to use same variable names, table names, etc. those exist in the real situation than come up with new names. The problem could be even a variable, table etc. name related! Rare case perhaps, but better safe than sorry. After all it should be easier for you to use the same situation in your example that you really had and it is by all means better for us. In case you have some data you don't want to show to others, you can use ftp to transfer the data to ftp://www.mysql.com/pub/mysql/secret. If the data is really top secret and you don't want to show it even to us, then go ahead and make an example using other variable names, etc., but please regard it as the last choice.
• If a program gives an error message, it is very important to state it! One should never try to remember what the error message was, but copy and paste the whole error message into the mail!
• Include all the options given to the relevant programs, if possible. For example, the options to the mysqld daemon and to any MySQL client programs. The options to mysqld ,mysql or to configure script are often keys to answers and very relevant! It is never a bad idea to include them anyway! If you use any modules, like Perl or PHP, please include the version number(s) of these.
• If you can't produce a test case in a few rows, or if the test table is too big to be mailed to everyone (more than 10 rows), you should dump your tables using mysqldump and create a `README' file that describes your problem. Use tar and gzip or zip on the files and use ftp to transfer the archive to ftp://www.mysql.com/pub/mysql/secret. Then send a short description of the problem to mysql@tcx.se.
• If your question is related to the privilege system, please include the output of mysqlaccess (can be found from the scripts directory), the output of mysqladmin reload and all the error messages you get when trying to connect! You should do all the tests in the order above!
• If you have a patch for a bug, it's good. If the patch is good, then very good. Still, don't expect that we will use the patch anyway and omit some necessary information, like a test case, thinking that the patch is all we need. We might found problems with your patch or don't understand it at all and if so, we don't use the patch. If we can't verify what the patch is exactly meant for, we don't use it. A test case will help us here. Show that the patch will handle all the situations that may happen. If we found, even a rare borderline case, there the patch won't work, the patch may be useless.
• A guess about what the bug is, why it occurs, or what it depends on, is usually wrong. Even we can't guess such things without first using a debugger to find out where the bug really comes from.
• Indicate in your mail message that you have checked the reference manual and mail archive so others know that you have tried to solve your problem yourself.
• If you get a parse error please check your syntax closely! If you can't find something wrong with it, it's extremely likely that your current version of MySQL doesn't support the query you are using! In this case you should check the MySQL change history for when the syntax was implemented! See section D MySQL change history If the manual at http://www.mysql.com/doc.html doesn't cover the query syntax you are using, this means that MySQL doesn't yet support this! In this case your only options are to implement this yourself or email
• If possible download the newest MySQL version and test if your problem is solved in this! All MySQL versions are throughly tested and should work without problems! We believe in making everything as backward compatible as possible and you should be able to switch MySQL version in minutes! See section 4.3 Which MySQL version to use.

If you are a support customer, please cross post the bug report to well as to the appropriate mailing list to see if someone else has experienced (and perhaps solved) the problem.

For information on reporting bugs in MyODBC, see section 15.2 How to report problems with MyODBC.

When answers are sent to you individually and not to the mailing list, it is considered good etiquette to summarize the answers and send the summary to the mailing list to that others may have the benefit of the responses you received that helped you solve your problem!.

2.3.1 What to do if MySQL keeps crashing

Since it is very hard to know why something is crashing, first try to check whether or not things that work for others crash for you. Please try the following things:

• Have you tried the benchmarks? This should test MySQL rather well. You can also add code that simulates your application!
• Try fork_test.pl and fork2_test.pl.
• If you configure MySQL for debugging, it will be much easier to find out possible errors if something goes wrong. See section 19.10 Debugging MySQL.
• Reconfigure MySQL with the --with-debug option to configure and then recompile. This causes a safe memory allocator to be included that can find some errors. It also provides a lot of output about what is happening.
• Use mysqld --log and try to determine from the information in the log whether or not some specific query kills the server. 95% of all bugs are related to some specific query!
• Have you applied the latest patches for your operating system?
• Use the --skip-locking option to mysqld. On some systems, the lockd lock manager does not work properly; the --skip-locking option tells mysqld not to use external locking. (This means that you cannot run 2 mysqld servers on the same data and you must be careful when using isamchk, but it may be instructive to try the option as a test.)
• Have you tried mysqladmin -u root processlist when mysqld appears to be dead? Sometimes mysqld is not dead even though you might think so. The problem may be that all connections are in use, or there may be some internal lock problem. mysqladmin processlist will usually be able to make a connection even in these cases, and can provide useful information about the current number of connections and their status.
• Run the command mysqladmin -i 5 status in a separate window to output statistics.
• Try the following:
  1. Start mysqld from gdb (or another debugger).
  2. Run your test scripts.
  3. Do back (or the backtrace command in your debugger) when mysqld core dumps.
• Try to simulate your application with a Perl script to force MySQL to crash or misbehave.
• Or send a normal bug report. See section 2.3 How to report bugs / problems. But be even more detailed than usual. Since MySQL works for many people it may be that the crash results from something that exists only on your computer (for example, an error that is related to your particular system libraries).

2.4 Guidelines for answering questions on the mailing list

If you consider your answer to have broad interest, you may want to post it to the mailing list instead of replying directly to the individual who asked. Try to make your answer general enough that people other than the original poster may benefit from it. When you post to the list, please make sure that your answer is not a duplication of a previous answer.

Try to summarize the essential part of the question in your reply, but don't feel obliged to quote the whole question.

Please don't post mails from your browser with HTML mode turned on! Many users doesn't read mails with a browser!

This document was generated on 3 January 1999 using the texi2html translator version 1.52 (extended by davida@detron.se).