Using Perl Stored Procedures for MariaDB
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This document discusses using Perl stored procedures with MariaDB. Key points include: - Perl stored procedures are implemented as Perl modules that use DBD::mysql to access the database from within the MariaDB process. This makes them easier to debug than SQL stored routines. - Examples are provided for simple "Hello World" procedures, handling errors, reading and returning data from queries, and modifying data by inserting rows. - Perl stored procedures allow extending MariaDB's functionality by leveraging thousands of modules on CPAN. As an example, the document shows how a procedure could implement a basic monitoring server using HTTP::Daemon to expose server status data via a JSON API.
![Hello World
MariaDB [Demo]> CREATE PROCEDURE PerlHello()
-> DYNAMIC RESULT SETS 1
-> NO SQL
-> LANGUAGE Perl
-> EXTERNAL NAME "HelloWorld::test";
Query OK, 0 rows affected (0.02 sec)
MariaDB [Demo]> call PerlHello();
+-----------------------+
| message |
+-----------------------+
| Hello World from Perl |
+-----------------------+
1 row in set (0.03 sec)
Query OK, 0 rows affected (0.03 sec)
package HelloWorld;
# put this file in <prefix>/lib/mysql/perl
use 5.008008;
use strict;
use warnings;
use Symbol qw(delete_package);
require Exporter;
our @ISA = qw(Exporter);
our @EXPORT_OK = qw( );
our @EXPORT = qw( test );
our $VERSION = '0.01';
sub test()
{
return {
'message' => 'Hello World from Perl',
};
}
1;](https://image.slidesharecdn.com/perlstoredprocedures2013-130425182647-phpapp01/85/Using-Perl-Stored-Procedures-for-MariaDB-4-320.jpg)
![Hello World
MariaDB [Demo]> CREATE PROCEDURE PerlHello()
-> DYNAMIC RESULT SETS 1
-> NO SQL
-> LANGUAGE Perl
-> EXTERNAL NAME "HelloWorld::test";
Query OK, 0 rows affected (0.02 sec)
MariaDB [Demo]> call PerlHello();
+-----------------------+
| message |
+-----------------------+
| Hello World from Perl |
+-----------------------+
1 row in set (0.03 sec)
Query OK, 0 rows affected (0.03 sec)
package HelloWorld;
# put this file in <prefix>/lib/mysql/perl
use 5.008008;
use strict;
use warnings;
use Symbol qw(delete_package);
require Exporter;
our @ISA = qw(Exporter);
our @EXPORT_OK = qw( );
our @EXPORT = qw( test );
our $VERSION = '0.01';
sub test()
{
return {
'message' => 'Hello World from Perl',
};
}
1;](https://image.slidesharecdn.com/perlstoredprocedures2013-130425182647-phpapp01/85/Using-Perl-Stored-Procedures-for-MariaDB-5-320.jpg)
![Error handling or die
MariaDB [Demo]> CREATE PROCEDURE PerlError()
-> DYNAMIC RESULT SETS 1
-> NO SQL
-> LANGUAGE Perl
-> EXTERNAL NAME "GoodbyeWorld::test";
Query OK, 0 rows affected (0.00 sec)
MariaDB [Demo]> call PerlError();
ERROR 1220 (HY000): Cannot open file: No
such file or directory at /usr/local/mysql/
lib/plugin/perl/GoodbyeWorld.pm line 16.
package GoodbyeWorld;
# put this file in <prefix>/lib/mysql/perl
use 5.008008;
use strict;
use warnings;
use Symbol qw(delete_package);
require Exporter;
our @ISA = qw(Exporter);
our @EXPORT_OK = qw( );
our @EXPORT = qw( test );
our $VERSION = '0.01';
sub test(
{
open FILE, "</something/nonexist"
or die "Cannot open file: $!";
return {
'message' => 'Goodbye World from Perl',
};
}
1;](https://image.slidesharecdn.com/perlstoredprocedures2013-130425182647-phpapp01/85/Using-Perl-Stored-Procedures-for-MariaDB-6-320.jpg)
![Reading Data
MariaDB [employees]> CREATE PROCEDURE employee(
-> empno INT)
-> DYNAMIC RESULT SETS 1
-> READS SQL DATA
-> LANGUAGE Perl
-> EXTERNAL NAME "ReadData::test";
Query OK, 0 rows affected (0.02 sec)
MariaDB [employees]> call employee(10034)G
*************************** 1. row
***************************
birth_date: 1962-12-29
emp_no: 10034
first_name: Bader
gender: M
hire_date: 1988-09-21
last_name: Swan
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.00 sec)
package ReadData;
# put this file in <prefix>/lib/mysql/perl
use 5.008008;
use strict;
use warnings;
use Symbol qw(delete_package);
require Exporter;
our @ISA = qw(Exporter);
our @EXPORT_OK = qw( );
our @EXPORT = qw( test );
our $VERSION = '0.01';
our $DSN = ‘dbi:mysql:employees’;
use DBI;
use DBD::mysql;
sub test($)
{
my($emp_no) = @_;
my $dbh = DBI->connect($DSN, undef, undef) ||
die "Failed in call to DBI->connect, $!";
my $s = $dbh->prepare(
“SELECT * FROM employees WHERE emp_no=?”);
$s->execute(int $emp_no);
return $s->fetchrow_hashref;
}
1;](https://image.slidesharecdn.com/perlstoredprocedures2013-130425182647-phpapp01/85/Using-Perl-Stored-Procedures-for-MariaDB-7-320.jpg)
![Reading Data
MariaDB [employees]> CREATE PROCEDURE employee(
-> empno INT)
-> DYNAMIC RESULT SETS 1
-> READS SQL DATA
-> LANGUAGE Perl
-> EXTERNAL NAME "ReadData::test";
Query OK, 0 rows affected (0.02 sec)
MariaDB [employees]> call employee(10034)G
*************************** 1. row
***************************
birth_date: 1962-12-29
emp_no: 10034
first_name: Bader
gender: M
hire_date: 1988-09-21
last_name: Swan
1 row in set (0.00 sec)
Query OK, 0 rows affected (0.00 sec)
package ReadData;
# put this file in <prefix>/lib/mysql/perl
use 5.008008;
use strict;
use warnings;
use Symbol qw(delete_package);
require Exporter;
our @ISA = qw(Exporter);
our @EXPORT_OK = qw( );
our @EXPORT = qw( test );
our $VERSION = '0.01';
our $DSN = ‘dbi:mysql:employees’;
use DBI;
use DBD::mysql;
sub test($)
{
my($emp_no) = @_;
my $dbh = DBI->connect($DSN, undef, undef) ||
die "Failed in call to DBI->connect, $!";
my $s = $dbh->prepare(
“SELECT * FROM employees WHERE emp_no=?”);
$s->execute(int $emp_no);
return $s->fetchrow_hashref;
}
1;](https://image.slidesharecdn.com/perlstoredprocedures2013-130425182647-phpapp01/85/Using-Perl-Stored-Procedures-for-MariaDB-8-320.jpg)
![Modifying Data
MariaDB [employees]> CREATE PROCEDURE
-> makesummary(
-> empno INT)
-> MODIFIES SQL DATA
-> LANGUAGE Perl
-> EXTERNAL NAME "ModifyData::test";
Query OK, 0 rows affected (0.00 sec)
MariaDB [employees]> call makesummary;
sub test()
{
my $dbh = DBI->connect($DSN, undef, undef) ||
die "Failed in call to DBI->connect, $!";
$dbh->begin_work or die $!;
my $ins = $dbh->prepare("INSERT INTO summary VALUES (?,?)");
my $emps = $dbh->selectall_arrayref(
"select emp_no, max(salary) salary from employees ".
"left join salaries using (emp_no) group by emp_no",
{ Slice => {} });
foreach my $emp (@$emps)
{
$ins->execute($emp->{emp_no}, $emp->{salary}) or die $!;
}
$dbh->commit or die $!;
return undef;
}](https://image.slidesharecdn.com/perlstoredprocedures2013-130425182647-phpapp01/85/Using-Perl-Stored-Procedures-for-MariaDB-9-320.jpg)
![Modifying Data
MariaDB [employees]> CREATE PROCEDURE
-> makesummary(
-> empno INT)
-> MODIFIES SQL DATA
-> LANGUAGE Perl
-> EXTERNAL NAME "ModifyData::test";
Query OK, 0 rows affected (0.00 sec)
MariaDB [employees]> call makesummary;
Query OK, 0 rows affected (18.02 sec)
sub test()
{
my $dbh = DBI->connect($DSN, undef, undef) ||
die "Failed in call to DBI->connect, $!";
$dbh->begin_work or die $!;
my $ins = $dbh->prepare("INSERT INTO summary VALUES (?,?)");
my $emps = $dbh->selectall_arrayref(
"select emp_no, max(salary) salary from employees ".
"left join salaries using (emp_no) group by emp_no",
{ Slice => {} });
foreach my $emp (@$emps)
{
$ins->execute($emp->{emp_no}, $emp->{salary}) or die $!;
}
$dbh->commit or die $!;
return undef;
}](https://image.slidesharecdn.com/perlstoredprocedures2013-130425182647-phpapp01/85/Using-Perl-Stored-Procedures-for-MariaDB-10-320.jpg)
![Modifying Data
MariaDB [employees]> CREATE PROCEDURE
-> makesummary(
-> empno INT)
-> MODIFIES SQL DATA
-> LANGUAGE Perl
-> EXTERNAL NAME "ModifyData::test";
Query OK, 0 rows affected (0.00 sec)
MariaDB [employees]> call makesummary;
Query OK, 0 rows affected (18.02 sec)
MariaDB [employees]> select count(*)
-> from summary;
+----------+
| count(*) |
+----------+
| 300024 |
+----------+
1 row in set (0.15 sec)
sub test()
{
my $dbh = DBI->connect($DSN, undef, undef) ||
die "Failed in call to DBI->connect, $!";
$dbh->begin_work or die $!;
my $ins = $dbh->prepare("INSERT INTO summary VALUES (?,?)");
my $emps = $dbh->selectall_arrayref(
"select emp_no, max(salary) salary from employees ".
"left join salaries using (emp_no) group by emp_no",
{ Slice => {} });
foreach my $emp (@$emps)
{
$ins->execute($emp->{emp_no}, $emp->{salary}) or die $!;
}
$dbh->commit or die $!;
return undef;
}](https://image.slidesharecdn.com/perlstoredprocedures2013-130425182647-phpapp01/85/Using-Perl-Stored-Procedures-for-MariaDB-11-320.jpg)
![Modifying Data
MariaDB [employees]> CREATE PROCEDURE
-> makesummary(
-> empno INT)
-> MODIFIES SQL DATA
-> LANGUAGE Perl
-> EXTERNAL NAME "ModifyData::test";
Query OK, 0 rows affected (0.00 sec)
MariaDB [employees]> call makesummary;
Query OK, 0 rows affected (18.02 sec)
MariaDB [employees]> select count(*)
-> from summary;
+----------+
| count(*) |
+----------+
| 300024 |
+----------+
1 row in set (0.15 sec)
sub test()
{
my $dbh = DBI->connect($DSN, undef, undef) ||
die "Failed in call to DBI->connect, $!";
$dbh->begin_work or die $!;
my $ins = $dbh->prepare("INSERT INTO summary VALUES (?,?)");
my $emps = $dbh->selectall_arrayref(
"select emp_no, max(salary) salary from employees ".
"left join salaries using (emp_no) group by emp_no",
{ Slice => {} });
foreach my $emp (@$emps)
{
$ins->execute($emp->{emp_no}, $emp->{salary}) or die $!;
}
$dbh->commit or die $!;
return undef;
}
select statement - 2 seconds
300k inserts in 16 seconds
== 18k inserts per second](https://image.slidesharecdn.com/perlstoredprocedures2013-130425182647-phpapp01/85/Using-Perl-Stored-Procedures-for-MariaDB-12-320.jpg)
![Server Monitoring
'/statusz' => sub {
my ($dbh,$c,$r) = @_;
return $c->send_error(RC_FORBIDDEN)
if $r->method ne 'GET';
my $sth = $dbh->prepare_cached(q{
SELECT VARIABLE_NAME name, VARIABLE_VALUE value
FROM INFORMATION_SCHEMA.GLOBAL_STATUS
}, { Slice => {} });
$sth->execute() || die $sth->errstr;
my $response = HTTP::Response->new(200, undef,
HTTP::Headers->new(
Content_Type => "application/json",
));
my $result = {};
while (my $row = $sth->fetchrow_arrayref)
{
$result->{$row->[0]} = $row->[1];
}
$response->add_content(to_json($result,
{ ascii => 1, pretty => 1 }));
return $c->send_response($response);
},
Fetching current
server status could be
as simple as fetching
http://127.0.0.1/statusz](https://image.slidesharecdn.com/perlstoredprocedures2013-130425182647-phpapp01/85/Using-Perl-Stored-Procedures-for-MariaDB-15-320.jpg)
Using Perl Stored Procedures for MariaDB
- 1. Using Perl Stored Procedures with MariaDB Antony T Curtis <atcurtis@gmail.com> Special thanks to LinkedIn for permitting personal projects
- 2. Why Perl? • CPAN • "Multiplicity" / Thread-friendly. • Lots of Perl code already written. • MySQL UDFs have no access control. • MySQL UDFs cannot execute dynamic SQL. • Faster than “native” Stored Procedures.
- 3. Perl Stored Procedures • Implemented as Perl modules. • Use DBD::mysql to access database. • Runs in-process with MariaDB. • Easier to debug than SQL stored routines.
- 4. Hello World MariaDB [Demo]> CREATE PROCEDURE PerlHello() -> DYNAMIC RESULT SETS 1 -> NO SQL -> LANGUAGE Perl -> EXTERNAL NAME "HelloWorld::test"; Query OK, 0 rows affected (0.02 sec) MariaDB [Demo]> call PerlHello(); +-----------------------+ | message | +-----------------------+ | Hello World from Perl | +-----------------------+ 1 row in set (0.03 sec) Query OK, 0 rows affected (0.03 sec) package HelloWorld; # put this file in <prefix>/lib/mysql/perl use 5.008008; use strict; use warnings; use Symbol qw(delete_package); require Exporter; our @ISA = qw(Exporter); our @EXPORT_OK = qw( ); our @EXPORT = qw( test ); our $VERSION = '0.01'; sub test() { return { 'message' => 'Hello World from Perl', }; } 1;
- 5. Hello World MariaDB [Demo]> CREATE PROCEDURE PerlHello() -> DYNAMIC RESULT SETS 1 -> NO SQL -> LANGUAGE Perl -> EXTERNAL NAME "HelloWorld::test"; Query OK, 0 rows affected (0.02 sec) MariaDB [Demo]> call PerlHello(); +-----------------------+ | message | +-----------------------+ | Hello World from Perl | +-----------------------+ 1 row in set (0.03 sec) Query OK, 0 rows affected (0.03 sec) package HelloWorld; # put this file in <prefix>/lib/mysql/perl use 5.008008; use strict; use warnings; use Symbol qw(delete_package); require Exporter; our @ISA = qw(Exporter); our @EXPORT_OK = qw( ); our @EXPORT = qw( test ); our $VERSION = '0.01'; sub test() { return { 'message' => 'Hello World from Perl', }; } 1;
- 6. Error handling or die MariaDB [Demo]> CREATE PROCEDURE PerlError() -> DYNAMIC RESULT SETS 1 -> NO SQL -> LANGUAGE Perl -> EXTERNAL NAME "GoodbyeWorld::test"; Query OK, 0 rows affected (0.00 sec) MariaDB [Demo]> call PerlError(); ERROR 1220 (HY000): Cannot open file: No such file or directory at /usr/local/mysql/ lib/plugin/perl/GoodbyeWorld.pm line 16. package GoodbyeWorld; # put this file in <prefix>/lib/mysql/perl use 5.008008; use strict; use warnings; use Symbol qw(delete_package); require Exporter; our @ISA = qw(Exporter); our @EXPORT_OK = qw( ); our @EXPORT = qw( test ); our $VERSION = '0.01'; sub test( { open FILE, "</something/nonexist" or die "Cannot open file: $!"; return { 'message' => 'Goodbye World from Perl', }; } 1;
- 7. Reading Data MariaDB [employees]> CREATE PROCEDURE employee( -> empno INT) -> DYNAMIC RESULT SETS 1 -> READS SQL DATA -> LANGUAGE Perl -> EXTERNAL NAME "ReadData::test"; Query OK, 0 rows affected (0.02 sec) MariaDB [employees]> call employee(10034)G *************************** 1. row *************************** birth_date: 1962-12-29 emp_no: 10034 first_name: Bader gender: M hire_date: 1988-09-21 last_name: Swan 1 row in set (0.00 sec) Query OK, 0 rows affected (0.00 sec) package ReadData; # put this file in <prefix>/lib/mysql/perl use 5.008008; use strict; use warnings; use Symbol qw(delete_package); require Exporter; our @ISA = qw(Exporter); our @EXPORT_OK = qw( ); our @EXPORT = qw( test ); our $VERSION = '0.01'; our $DSN = ‘dbi:mysql:employees’; use DBI; use DBD::mysql; sub test($) { my($emp_no) = @_; my $dbh = DBI->connect($DSN, undef, undef) || die "Failed in call to DBI->connect, $!"; my $s = $dbh->prepare( “SELECT * FROM employees WHERE emp_no=?”); $s->execute(int $emp_no); return $s->fetchrow_hashref; } 1;
- 8. Reading Data MariaDB [employees]> CREATE PROCEDURE employee( -> empno INT) -> DYNAMIC RESULT SETS 1 -> READS SQL DATA -> LANGUAGE Perl -> EXTERNAL NAME "ReadData::test"; Query OK, 0 rows affected (0.02 sec) MariaDB [employees]> call employee(10034)G *************************** 1. row *************************** birth_date: 1962-12-29 emp_no: 10034 first_name: Bader gender: M hire_date: 1988-09-21 last_name: Swan 1 row in set (0.00 sec) Query OK, 0 rows affected (0.00 sec) package ReadData; # put this file in <prefix>/lib/mysql/perl use 5.008008; use strict; use warnings; use Symbol qw(delete_package); require Exporter; our @ISA = qw(Exporter); our @EXPORT_OK = qw( ); our @EXPORT = qw( test ); our $VERSION = '0.01'; our $DSN = ‘dbi:mysql:employees’; use DBI; use DBD::mysql; sub test($) { my($emp_no) = @_; my $dbh = DBI->connect($DSN, undef, undef) || die "Failed in call to DBI->connect, $!"; my $s = $dbh->prepare( “SELECT * FROM employees WHERE emp_no=?”); $s->execute(int $emp_no); return $s->fetchrow_hashref; } 1;
- 9. Modifying Data MariaDB [employees]> CREATE PROCEDURE -> makesummary( -> empno INT) -> MODIFIES SQL DATA -> LANGUAGE Perl -> EXTERNAL NAME "ModifyData::test"; Query OK, 0 rows affected (0.00 sec) MariaDB [employees]> call makesummary; sub test() { my $dbh = DBI->connect($DSN, undef, undef) || die "Failed in call to DBI->connect, $!"; $dbh->begin_work or die $!; my $ins = $dbh->prepare("INSERT INTO summary VALUES (?,?)"); my $emps = $dbh->selectall_arrayref( "select emp_no, max(salary) salary from employees ". "left join salaries using (emp_no) group by emp_no", { Slice => {} }); foreach my $emp (@$emps) { $ins->execute($emp->{emp_no}, $emp->{salary}) or die $!; } $dbh->commit or die $!; return undef; }
- 10. Modifying Data MariaDB [employees]> CREATE PROCEDURE -> makesummary( -> empno INT) -> MODIFIES SQL DATA -> LANGUAGE Perl -> EXTERNAL NAME "ModifyData::test"; Query OK, 0 rows affected (0.00 sec) MariaDB [employees]> call makesummary; Query OK, 0 rows affected (18.02 sec) sub test() { my $dbh = DBI->connect($DSN, undef, undef) || die "Failed in call to DBI->connect, $!"; $dbh->begin_work or die $!; my $ins = $dbh->prepare("INSERT INTO summary VALUES (?,?)"); my $emps = $dbh->selectall_arrayref( "select emp_no, max(salary) salary from employees ". "left join salaries using (emp_no) group by emp_no", { Slice => {} }); foreach my $emp (@$emps) { $ins->execute($emp->{emp_no}, $emp->{salary}) or die $!; } $dbh->commit or die $!; return undef; }
- 11. Modifying Data MariaDB [employees]> CREATE PROCEDURE -> makesummary( -> empno INT) -> MODIFIES SQL DATA -> LANGUAGE Perl -> EXTERNAL NAME "ModifyData::test"; Query OK, 0 rows affected (0.00 sec) MariaDB [employees]> call makesummary; Query OK, 0 rows affected (18.02 sec) MariaDB [employees]> select count(*) -> from summary; +----------+ | count(*) | +----------+ | 300024 | +----------+ 1 row in set (0.15 sec) sub test() { my $dbh = DBI->connect($DSN, undef, undef) || die "Failed in call to DBI->connect, $!"; $dbh->begin_work or die $!; my $ins = $dbh->prepare("INSERT INTO summary VALUES (?,?)"); my $emps = $dbh->selectall_arrayref( "select emp_no, max(salary) salary from employees ". "left join salaries using (emp_no) group by emp_no", { Slice => {} }); foreach my $emp (@$emps) { $ins->execute($emp->{emp_no}, $emp->{salary}) or die $!; } $dbh->commit or die $!; return undef; }
- 12. Modifying Data MariaDB [employees]> CREATE PROCEDURE -> makesummary( -> empno INT) -> MODIFIES SQL DATA -> LANGUAGE Perl -> EXTERNAL NAME "ModifyData::test"; Query OK, 0 rows affected (0.00 sec) MariaDB [employees]> call makesummary; Query OK, 0 rows affected (18.02 sec) MariaDB [employees]> select count(*) -> from summary; +----------+ | count(*) | +----------+ | 300024 | +----------+ 1 row in set (0.15 sec) sub test() { my $dbh = DBI->connect($DSN, undef, undef) || die "Failed in call to DBI->connect, $!"; $dbh->begin_work or die $!; my $ins = $dbh->prepare("INSERT INTO summary VALUES (?,?)"); my $emps = $dbh->selectall_arrayref( "select emp_no, max(salary) salary from employees ". "left join salaries using (emp_no) group by emp_no", { Slice => {} }); foreach my $emp (@$emps) { $ins->execute($emp->{emp_no}, $emp->{salary}) or die $!; } $dbh->commit or die $!; return undef; } select statement - 2 seconds 300k inserts in 16 seconds == 18k inserts per second
- 13. More than just procs • CPAN is a large library... • Can extend MariaDB’s functionality. • How about using HTTP::Daemon?
- 14. Server Monitoring sub daemon() { my $d = HTTP::Daemon->new( LocalAddr => '127.0.0.1', LocalPort => 8080, ) || die "Failed in call to HTTP::Daemon->new, $!"; my $dbh = DBI->connect("dbi:mysql:mysql", undef, undef) || die "Failed in call to DBI->connect, $!"; while (my $c = $d->accept) { while (my $r = $c->get_request) { if (exists $pages{$r->url->path}) { $pages{$r->url->path}->($dbh, $c, $r); } else { $c->send_error(RC_NOT_FOUND); } } $c->close; undef $c; } } What if we can use HTTP::Daemon?
- 15. Server Monitoring '/statusz' => sub { my ($dbh,$c,$r) = @_; return $c->send_error(RC_FORBIDDEN) if $r->method ne 'GET'; my $sth = $dbh->prepare_cached(q{ SELECT VARIABLE_NAME name, VARIABLE_VALUE value FROM INFORMATION_SCHEMA.GLOBAL_STATUS }, { Slice => {} }); $sth->execute() || die $sth->errstr; my $response = HTTP::Response->new(200, undef, HTTP::Headers->new( Content_Type => "application/json", )); my $result = {}; while (my $row = $sth->fetchrow_arrayref) { $result->{$row->[0]} = $row->[1]; } $response->add_content(to_json($result, { ascii => 1, pretty => 1 })); return $c->send_response($response); }, Fetching current server status could be as simple as fetching http://127.0.0.1/statusz
- 16. Status • Code hosted at LaunchPad. • Contributing to MariaDB 10.0 soon. • Stuff needs to be tidied up. • Future steps include better Table Functions.