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.
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.