Connect with Perl

The following example installs the Perl drivers with the basic CPAN method:

$ perl -MCPAN -e shell
cpan> install DBI
cpan> install DBD::mysql

This command installed the following version of DBI and DBD:

perl -MDBI -e 'print $DBI::VERSION."\n"'  # 1.642
perl -MDBD::mysql -e 'print $DBD::mysql::VERSION."\n"'  # 4.050

Here's a sample script to test connectivity using the installed drivers. The following script connects to a cluster and retrieves some basic information about the cluster.

#!/usr/bin/perl
use strict;
use DBI;

my $host = "<ip_address_or_hostname";
my $database = "information_schema"; my $port = 3306;
my $tablename = "mv_activities";
my $user = "root";
my $pw = "";
my $dbh = DBI->connect("DBI:mysql:database=$database;host=$host",$user, $pw) or die "Cannot connect to MySQL server\n";
my $sql = 'select @@memsql_version';
my $sth = $dbh->prepare($sql);
$sth->execute();

while (my @row = $sth->fetchrow_array) {
  print "MemSQL_Version: $row[0] \n";
}

my $sql = 'select count(*) from aggregators';
my $sth = $dbh->prepare($sql);
$sth->execute();
while (my @row = $sth->fetchrow_array) {
  print "Aggregators: $row[0] \n";
}

my $sql = 'select count(*) from leaves';
my $sth = $dbh->prepare($sql);
$sth->execute();
while (my @row = $sth->fetchrow_array) {
  print "Leaves $row[0] \n";
}

my $sql = 'select variable_name, variable_value from information_schema.global_status where variable_name = "uptime"';
my $sth = $dbh->prepare($sql);
$sth->execute();
while (my @row = $sth->fetchrow_array) {
#print "variable_name $row[0] variable_value $row[1]\n";
print "Cluster has been up for $row[1] seconds! \n";
}

Replace ip_address_or_hostname in the code above with the IP address or the hostname of your cluster. Here's a sample output:

$ ./show_cluster.pm
MemSQL_Version: 6.7.14 Aggregators: 1
Leaves 2
Cluster has been up for 16025 seconds!

The following example shows how to use Kerberos authentication with the script above. Since, the script is compiled locally with CPAN, it works out of the box. Remember to comment out the password line.

#my $pw = "";
#my $dbh = DBI->connect("DBI:mysql:database=$database;host=$host",$user, $pw) or die "Cannot connect to MySQL server\n";
my $dbh = DBI->connect("DBI:mysql:database=$database;host=$host",$user ) or die "Cannot connect to MySQL server\n";

Here's a sample output:

[ec2-user perl]$ klist
Ticket cache: KEYRING:persistent:1000:1000
Default principal: tron@LOCALHOST

Valid starting       Expires              Service principal
04/15/2019 23:47:37  04/16/2019 23:31:56  memsql/memsql.localhost@LOCALHOST
04/15/2019 23:31:56  04/16/2019 23:31:56  krbtgt/LOCALHOST@LOCALHOST

[ec2-user perl]$ ./show_cluster.pm
MemSQL_Version: 6.7.15
Aggregators: 1
Leaves 1
Cluster has been up for 1306 seconds!

SingleStoreDB also supports the MariaDB Perl Library v1.11 (GPLv2).