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pt-fifo-split

NAME

pt-fifo-split - Split files and pipe lines to a fifo without really splitting.

SYNOPSIS

Usage

pt-fifo-split [OPTIONS] [FILE]

pt-fifo-split splits FILE and pipes lines to a fifo. With no FILE, or when FILE is -, read standard input.

Read hugefile.txt in chunks of a million lines without physically splitting it:

pt-fifo-split --lines 1000000 hugefile.txt
while [ -e /tmp/pt-fifo-split ]; do cat /tmp/pt-fifo-split; done

RISKS

Percona Toolkit is mature, proven in the real world, and well tested, but all database tools can pose a risk to the system and the database server. Before using this tool, please:

  • Read the tool’s documentation

  • Review the tool’s known “BUGS”

  • Test the tool on a non-production server

  • Backup your production server and verify the backups

DESCRIPTION

pt-fifo-split lets you read from a file as though it contains only some of the lines in the file. When you read from it again, it contains the next set of lines; when you have gone all the way through it, the file disappears. This works only on Unix-like operating systems.

You can specify multiple files on the command line. If you don’t specify any, or if you use the special filename -, lines are read from standard input.

OPTIONS

This tool accepts additional command-line arguments. Refer to the “SYNOPSIS” and usage information for details.

--config

type: Array

Read this comma-separated list of config files; if specified, this must be the first option on the command line.

--fifo

type: string; default: /tmp/pt-fifo-split

The name of the fifo from which the lines can be read.

--force

Remove the fifo if it exists already, then create it again.

--help

Show help and exit.

--lines

type: int; default: 1000

The number of lines to read in each chunk.

--offset

type: int; default: 0

Begin at the Nth line. If the argument is 0, all lines are printed to the fifo. If 1, then beginning at the first line, lines are printed (exactly the same as 0). If 2, the first line is skipped, and the 2nd and subsequent lines are printed to the fifo.

--pid

type: string

Create the given PID file. The tool won’t start if the PID file already exists and the PID it contains is different than the current PID. However, if the PID file exists and the PID it contains is no longer running, the tool will overwrite the PID file with the current PID. The PID file is removed automatically when the tool exits.

--statistics

Print out statistics between chunks. The statistics are the number of chunks, the number of lines, elapsed time, and lines per second overall and during the last chunk.

--version

Show version and exit.

ENVIRONMENT

The environment variable PTDEBUG enables verbose debugging output to STDERR. To enable debugging and capture all output to a file, run the tool like:

PTDEBUG=1 pt-fifo-split ... > FILE 2>&1

Be careful: debugging output is voluminous and can generate several megabytes of output.

ATTENTION

Using <PTDEBUG> might expose passwords. When debug is enabled, all command line parameters are shown in the output.

SYSTEM REQUIREMENTS

You need Perl, DBI, DBD::mysql, and some core packages that ought to be installed in any reasonably new version of Perl.

BUGS

For a list of known bugs, see https://jira.percona.com/projects/PT/issues.

Please report bugs at https://jira.percona.com/projects/PT. Include the following information in your bug report:

  • Complete command-line used to run the tool

  • Tool --version

  • MySQL version of all servers involved

  • Output from the tool including STDERR

  • Input files (log/dump/config files, etc.)

If possible, include debugging output by running the tool with PTDEBUG; see “ENVIRONMENT”.

DOWNLOADING

Visit http://www.percona.com/software/percona-toolkit/ to download the latest release of Percona Toolkit. Or, get the latest release from the command line:

wget percona.com/get/percona-toolkit.tar.gz

wget percona.com/get/percona-toolkit.rpm

wget percona.com/get/percona-toolkit.deb

You can also get individual tools from the latest release:

wget percona.com/get/TOOL

Replace TOOL with the name of any tool.

AUTHORS

Baron Schwartz

ABOUT PERCONA TOOLKIT

This tool is part of Percona Toolkit, a collection of advanced command-line tools for MySQL developed by Percona. Percona Toolkit was forked from two projects in June, 2011: Maatkit and Aspersa. Those projects were created by Baron Schwartz and primarily developed by him and Daniel Nichter. Visit http://www.percona.com/software/ to learn about other free, open-source software from Percona.

VERSION

pt-fifo-split 3.6.0