SYNTAX

The syntax of the configuration files is as follows:

• Whitespace followed by a hash sign (#) signifies that the rest of the line is a comment. This is deleted. For example:
• Whitespace is stripped from the beginning and end of all lines.
• Empty lines are ignored.
• Each line is permitted to be in either of the following formats:

    option
    option=value
      

  Do not prefix the option with "--". Do not quote the values, even if it has spaces; value are literal. Whitespace around the equals sign is deleted during processing.

• Only long options are recognized.
• A line containing only two hyphens signals the end of option parsing. Any further lines are interpreted as additional arguments (not options) to the program.

EXAMPLE

This config file for pt-stalk,

  # Config for pt-stalk
  variable=Threads_connected
  cycles=2  # trigger if problem seen twice in a row
  --
  --user daniel

is equivalent to this command line:

  pt-stalk --variable Threads_connected --cycles 2 -- --user daniel

Options after "--" are passed literally to mysql and mysqladmin.

READ ORDER

The tools read several configuration files in order:

1.

The global Percona Toolkit configuration file, /etc/percona-toolkit/percona-toolkit.conf. All tools read this file, so you should only add options to it that you want to apply to all tools.

2.

The global tool-specific configuration file, /etc/percona-toolkit/TOOL.conf, where "TOOL" is a tool name like "pt-query-digest". This file is named after the specific tool you're using, so you can add options that apply only to that tool.

3.

The user's own Percona Toolkit configuration file, $HOME/.percona-toolkit.conf. All tools read this file, so you should only add options to it that you want to apply to all tools.

4.

The user's tool-specific configuration file, $HOME/.TOOL.conf, where "TOOL" is a tool name like "pt-query-digest". This file is named after the specific tool you're using, so you can add options that apply only to that tool.

SPECIFYING

There is a special "--config" option, which lets you specify which configuration files Percona Toolkit should read. You specify a comma-separated list of files. However, its behavior is not like other command-line options. It must be given first on the command line, before any other options. If you try to specify it anywhere else, it will cause an error. Also, you cannot specify "--config=/path/to/file"; you must specify the option and the path to the file separated by whitespace without an equal sign between them, like:

  --config /path/to/file

If you don't want any configuration files at all, specify "--config ''" to provide an empty list of files.

ESCAPING VALUES

DSNs are usually specified on the command line, so shell quoting and escaping must be taken into account. Special characters, like asterisk ("*"), need to be quoted and/or escaped properly to be passed as literal characters in DSN values.

Since DSN parts are separated by commas, literal commas in DSN values must be escaped with a single backslash ("\"). And since a backslash is the escape character for most shells, two backslashes are required to pass a literal backslash. For example, if the username is literally "my,name", it must be specified as "my\\,name" on most shells. This applies to DSNs and DSN-related options like "--user".

KEY PARTS

Many of the tools add more parts to DSNs for special purposes, and sometimes override parts to make them do something slightly different. However, all the tools support at least the following:

A

Default character set for the connection ("SET NAMES").

Enables character set settings in Perl and MySQL. If the value is "utf8", sets Perl's binmode on STDOUT to utf8, passes the "mysql_enable_utf8" option to DBD::mysql, and runs "SET NAMES 'utf8'" after connecting to MySQL. Other values set binmode on STDOUT without the utf8 layer and run "SET NAMES" after connecting to MySQL.

Unfortunately, there is no way from within Perl itself to specify the client library's character set. "SET NAMES" only affects the server; if the client library's settings don't match, there could be problems. You can use the defaults file to specify the client library's character set, however. See the description of the F part below.

D

Default database to use when connecting. Tools may "USE" a different databases while running.

F

Defaults file for the MySQL client library (the C client library used by DBD::mysql, not Percona Toolkit itself). All tools all read the "[client]" section within the defaults file. If you omit this, the standard defaults files will be read in the usual order. "Standard" varies from system to system, because the filenames to read are compiled into the client library. On Debian systems, for example, it's usually "/etc/mysql/my.cnf" then "~/.my.cnf". If you place the following in "~/.my.cnf", you won't have to specify your MySQL username and password on the command line:

  [client]
  user=your_user_name
  pass=secret
    

Omitting the F part is usually the right thing to do. As long as you have configured your "~/.my.cnf" correctly, that will result in tools connecting automatically without needing a username or password.

You can also specify a default character set in the defaults file. Unlike the "A" part described above, this will actually instruct the client library (DBD::mysql) to change the character set it uses internally, which cannot be accomplished any other way.

h

MySQL hostname or IP address to connect to.

L

Explicitly enable LOAD DATA LOCAL INFILE.

For some reason, some vendors compile libmysql without the --enable-local-infile option, which disables the statement. This can lead to weird situations, like the server allowing LOCAL INFILE, but the client throwing exceptions if it's used.

However, as long as the server allows LOAD DATA, clients can easily re-enable it; see <https://dev.mysql.com/doc/refman/5.0/en/load-data-local.html> and <http://search.cpan.org/~capttofu/DBD-mysql/lib/DBD/mysql.pm>. This option does exactly that.

p

MySQL password to use when connecting.

P

Port number to use for the connection. Note that the usual special-case behaviors apply: if you specify "localhost" as your hostname on Unix systems, the connection actually uses a socket file, not a TCP/IP connection, and thus ignores the port.

S

MySQL socket file to use for the connection (on Unix systems).

u

MySQL username to use when connecting, if not current system user.

BAREWORD

Many of the tools will let you specify a DSN as a single word, without any "key=value" syntax. This is called a 'bareword'. How this is handled is tool-specific, but it is usually interpreted as the "h" part. The tool's "--help" output will tell you the behavior for that tool.

PROPAGATION

Many tools will let you propagate values from one DSN to the next, so you don't have to specify all the parts for each DSN. For example, if you want to specify a username and password for each DSN, you can connect to three hosts as follows:

 h=host1,u=fred,p=wilma host2 host3

This is tool-specific.