MySql Database profiling and checking its result using perl - database

Question

I want to see how much time my query taking to execute using perl. Here is my work till now
#!/usr/bin/perl -w
use DBI;
use strict;
use warnings;
use diagnostics;
use POSIX qw(strftime);
my $driver = "mysql";
my $database = "employee";
my $dsn = "DBI:$driver:database=$database";
my $userid = "root";
my $password = "****";
my $sql_statement;
my $sth;
my $data;
my $row;
my $dbh = DBI->connect($dsn, $userid, $password ) or die $DBI::errstr;
my $foo = "SET profiling=on;"."\n"."SELECT * FROM employee;"."\n"."SHOW PROFILES;";
open my $fh, "<", \$foo;
binmode $fh, ":encoding(utf8)";
while ($sql_statement = <$fh>)
{
$data = $dbh->selectall_arrayref($sql_statement) or die "issue is : $dbh->errstr";
}
my $retirement_date;
if (scalar #$data)
{
$retirement_date = strftime( "%F %H:%M:%S", localtime(time() - #$data[0]));
}
print $retirement_date;
but I am not getting any result.
expected output should be like this
5 15.86296022 SELECT * from employee;
where 5 is query id, 15.86296022 is execution time and last query.
Please suggest how to achieve this.

Answer 1

You're not getting any result because you're misunderstanding the data structure you're getting back from selectall_arrayref(). It's an arrayref of arrayrefs - so you need to look two levels deep in it in order to get the actual data.
I replaced the second part of your code with this:
while ($sql_statement = <$fh>) {
warn "$sql_statement\n";
$data = $dbh->selectall_arrayref($sql_statement) or die "issue is : $dbh->errstr";
print join(' | ', #$_), "\n" for #$data;
}
And when I run it, I get this:
$ perl dbprofile
SET profiling=on;
DBD::mysql::db selectall_arrayref failed: fetch() without execute() at dbprofile line 25, <$fh> line 1.
SELECT * FROM employee;
1 | Fred | 2020-09-09
2 | Bill | 2035-06-23
3 | Jane | 2058-03-11
SHOW PROFILES;
1 | 0.00027717 | SELECT * FROM employee
I'm not sure what's going on with the "fetch() without execute()" error and I don't have time to investigate it now. But you can see all of your data - including the profiling information.

Answer 2

Please see if following demo code provides desired output
#!/usr/bin/perl
#
# vim: ai:ts=4:sw=4
#
use strict;
use warnings;
use feature 'say';
use DBI;
use Config::General;
my($dsn,$dbh,$sth,$query,$rv);
my $conf = Config::General->new( "$ENV{HOME}/.my.cnf" );
my %config = $conf->getall;
# Keep password inside code
$config{password} = 'your_password_here';
$dsn = "DBI:mysql:database=$config{database};host=$config{host};port=$config{port}";
$dbh = DBI->connect($dsn, $config{user}, $config{password},
{
RaiseError => 1,
mysql_enable_utf8 => 1
});
$query = "SET PROFILING=on";
$sth = $dbh->prepare($query) or die $dbh->errstr;
$rv = $sth->execute() or die $dbh->errstr;
#say $DBI::errstr if $rv < 0;
my $db_table = 'your_db_table_here';
$query = "SELECT * FROM $db_table";
$sth = $dbh->prepare($query) or die $dbh->errstr;
$rv = $sth->execute() or die $dbh->errstr;
#say $DBI::errstr if $rv < 0;
$query = "SHOW PROFILES";
$sth = $dbh->prepare($query) or die $dbh->errstr;
$rv = $sth->execute() or die $dbh->errstr;
#say $DBI::errstr if $rv < 0;
while( my $row = $sth->fetchrow_arrayref ) {
say join("\t",#{$row});
}
$query = "SET PROFILING=off";
$sth = $dbh->prepare($query) or die $dbh->errstr;
$rv = $sth->execute() or die $dbh->errstr;
#say $DBI::errstr if $rv < 0;
$sth->finish();
$dbh->disconnect();
Sample of $ENV{HOME}/.my.cnf file
[mysql]
host=yout_db_host_name
user=your_db_user_name
database=your_db_name
default-character-set=utf8
port=3306
Sample of output
1 0.0014745 SELECT * FROM new_movies