# DBI::ProfileDumper - phpMan

## NAME
    [DBI::ProfileDumper] - profile DBI usage and output data to a file

## SYNOPSIS
    To profile an existing program using [DBI::ProfileDumper], set the
    DBI_PROFILE environment variable and run your program as usual. For
    example, using bash:

      DBI_PROFILE=2/[DBI::ProfileDumper] program.pl

    Then analyze the generated file (dbi.prof) with dbiprof:

      dbiprof

    You can also activate [DBI::ProfileDumper] from within your code:

      use DBI;

      # profile with default path (2) and output file (dbi.prof)
      $dbh->{Profile} = "!Statement/[DBI::ProfileDumper]";

      # same thing, spelled out
      $dbh->{Profile} = "!Statement/[DBI::ProfileDumper]/File:dbi.prof";

      # another way to say it
      use [DBI::ProfileDumper];
      $dbh->{Profile} = [DBI::ProfileDumper]->new(
                            Path => [ '!Statement' ],
                            File => 'dbi.prof' );

      # using a custom path
      $dbh->{Profile} = [DBI::ProfileDumper]->new(
          Path => [ "foo", "bar" ],
          File => 'dbi.prof',
      );

## DESCRIPTION
    [DBI::ProfileDumper] is a subclass of [DBI::Profile] which dumps profile
    data to disk instead of printing a summary to your screen. You can then
    use dbiprof to analyze the data in a number of interesting ways, or you
    can roll your own analysis using [DBI::ProfileData].

    NOTE: For Apache/mod_perl applications, use [DBI::ProfileDumper::Apache].

## USAGE
    One way to use this module is just to enable it in your $dbh:

      $dbh->{Profile} = "1/[DBI::ProfileDumper]";

    This will write out profile data by statement into a file called
    dbi.prof. If you want to modify either of these properties, you can
    construct the [DBI::ProfileDumper] object yourself:

      use [DBI::ProfileDumper];
      $dbh->{Profile} = [DBI::ProfileDumper]->new(
          Path => [ '!Statement' ],
          File => 'dbi.prof'
      );

    The "Path" option takes the same values as in [DBI::Profile]. The "File"
    option gives the name of the file where results will be collected. If it
    already exists it will be overwritten.

    You can also activate this module by setting the DBI_PROFILE environment
    variable:

      $ENV{DBI_PROFILE} = "!Statement/[DBI::ProfileDumper]";

    This will cause all DBI handles to share the same profiling object.

## METHODS
    The following methods are available to be called using the profile
    object. You can get access to the profile object from the Profile key in
    any DBI handle:

      my $profile = $dbh->{Profile};

  flush_to_disk
      $profile->flush_to_disk()

    Flushes all collected profile data to disk and empties the Data hash.
    Returns the filename written to. If no profile data has been collected
    then the file is not written and flush_to_disk() returns undef.

    The file is locked while it's being written. A process 'consuming' the
    files while they're being written to, should rename the file first, then
    lock it, then read it, then close and delete it. The "DeleteFiles"
    option to [DBI::ProfileData] does the right thing.

    This method may be called multiple times during a program run.

  empty
      $profile->empty()

    Clears the Data hash without writing to disk.

  filename
      $filename = $profile->filename();

    Get or set the filename.

    The filename can be specified as a CODE reference, in which case the
    referenced code should return the filename to be used. The code will be
    called with the profile object as its first argument.

## DATA FORMAT
    The data format written by [DBI::ProfileDumper] starts with a header
    containing the version number of the module used to generate it. Then a
    block of variable declarations describes the profile. After two
    newlines, the profile data forms the body of the file. For example:

      [DBI::ProfileDumper] 2.003762
      Path = [ '!Statement', '!MethodName' ]
      Program = t/42profile_data.t

      + 1 SELECT name FROM users WHERE id = ?
      + 2 prepare
      = 1 0.0312958955764771 0.000490069389343262 0.000176072120666504 0.00140702724456787 1023115819.83019 1023115819.86576
      + 2 execute
      1 0.0312958955764771 0.000490069389343262 0.000176072120666504 0.00140702724456787 1023115819.83019 1023115819.86576
      + 2 fetchrow_hashref
      = 1 0.0312958955764771 0.000490069389343262 0.000176072120666504 0.00140702724456787 1023115819.83019 1023115819.86576
      + 1 UPDATE users SET name = ? WHERE id = ?
      + 2 prepare
      = 1 0.0312958955764771 0.000490069389343262 0.000176072120666504 0.00140702724456787 1023115819.83019 1023115819.86576
      + 2 execute
      = 1 0.0312958955764771 0.000490069389343262 0.000176072120666504 0.00140702724456787 1023115819.83019 1023115819.86576

    The lines beginning with "+" signs signify keys. The number after the
    "+" sign shows the nesting level of the key. Lines beginning with "="
    are the actual profile data, in the same order as in [DBI::Profile].

    Note that the same path may be present multiple times in the data file
    since "format()" may be called more than once. When read by
    [DBI::ProfileData] the data points will be merged to produce a single data
    set for each distinct path.

    The key strings are transformed in three ways. First, all backslashes
    are doubled. Then all newlines and carriage-returns are transformed into
    "\n" and "\r" respectively. Finally, any NULL bytes ("\0") are entirely
    removed. When [DBI::ProfileData] reads the file the first two
    transformations will be reversed, but NULL bytes will not be restored.

## AUTHOR
    Sam Tregar <<sam@tregar.com>>

## COPYRIGHT AND LICENSE
    Copyright (C) 2002 Sam Tregar

    This program is free software; you can redistribute it and/or modify it
    under the same terms as Perl 5 itself.