/ 
Queue-Q4Pg-Lite-0.03
River stage zero No dependents
/ Queue::Q4Pg::Lite

NAME

Queue::Q4Pg::Lite - Simple message queue using PostgreSQL

SYNOPSIS

use Queue::Q4Pg::Lite;

my $q = Queue::Q4Pg::Lite->connect(
  connect_info => [
    'dbi:Pg:dbname=mydb',
    $username,
    $password
  ],
);

for (1..10) {
  $q->insert($table, \%fieldvals);
}

while ($q->next($table)) {
  my $cols = $q->fetch_hashref()
  print "col1 = $cols->{col1}, col2 = $cols->{col2}, col3 = $cols->{col3}\n";
  $q->ack;
}

$q->disconnect;

# Table schema requires id column.
CREATE TABLE mq ( id SERIAL PRIMARY KEY, message TEXT );

DESCRIPTION

Queue::Q4Pg::Lite is a simple message queue using PostgreSQL which supports pg_advisory_lock (version 8.2 or later).

This algorithms was invented by http://d.hatena.ne.jp/n_shuyo/20090415/mq .

Many codes copied from Queue::Q4M.

METHODS

new

Creates a new Queue::Q4Pg::Lite instance. Normally you should use connect() instead.

connect

Connects to the target database.

my $q = Queue::Q4Pg::Lite->connect(
  connect_info => [
    'dbi:Pg:dbname=q4pg',
  ]
);

next($table, [$where]);

Blocks until the next item is available.

$where is same of arguments for SQL::Abstract->select($table, $col, $where)

# SELECT * FROM mq WHERE priority < 10;
$q->next("mq", { priority => { "<", 10 } });

fetch_hashref

Fetches the next available row as hashref.

my $hashref = $q->fetch_hashref();

ack

Delete the fetched row from table.

If You don't call ack(), the fetched row is not deleted from table.

insert($table, \%field)

Inserts into the queue. The first argument should be a scalar specifying a table name. The second argument is a hashref that specifies the mapping between column names and their respective values.

$q->insert($table, { col1 => $val1, col2 => $val2, col3 => $val3 });

clear($table);

Deletes everything the specified queue.

dbh

Returns the database handle after making sure that it's connected.

disconnect

Disconnects.

AUTHOR

FUJIWARA Shunichiro <fujiwara@cpan.org>

SEE ALSO

Queue::Q4M, SQL::Abstract, http://d.hatena.ne.jp/n_shuyo/20090415/mq

LICENSE

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