NAME

Mojo::PgX::Cursor - Cursor Extension for Mojo::Pg

SYNOPSIS

require Mojo::PgX::Cursor;
my $pg = Mojo::PgX::Cursor->new('postgresql://postgres@/test');
my $results = $pg->db->cursor('select * from some_big_table');
while (my $next = $results->hash) {
  say $next->{name};
}

DESCRIPTION

DBD::Pg fetches all rows when a statement is executed whereas other drivers usually fetch rows using the fetch* methods. Mojo::PgX::Cursor is an extension to work around this issue using PostgreSQL cursors while providing a Mojo::Pg-style API for iteratoring over the results; see Mojo::PgX::Cursor::Results for details.

METHODS

db

This subclass overrides Mojo::Pg's implementation in order to subclass the resulting Mojo::Pg::Database object into a Mojo::PgX::Cursor::Database.

VERSIONING

This module will follow Semantic Versioning 2.0.0. Once the API feels reasonable I'll release v1.0.0 which would correspond to 1.000000 according to version,

version->declare(q(v1.0.0))->numify # 1.000000
version->parse(q(1.000000))->normal # v1.0.0

MONKEYPATCH

require Mojo::Pg;
require Mojo::PgX::Cursor;
use Mojo::Util 'monkey_patch';
monkey_patch 'Mojo::Pg::Database', 'cursor', \&Mojo::PgX::Cursor::Database::cursor;

Just because you can doesn't mean you should but if you want you can monkey_patch Mojo::Pg::Database rather than swapping out your construction of Mojo::Pg objects with the Mojo::PgX::Cursor subclass.

DISCUSSION

This module would be unnecessary if DBD::Pg did not fetch all rows during execute and since libpq supports that it would be much better to fix fetch* than to implement this. However, I am not able to do so at this time.

CONTRIBUTING

If you would like to submit bug reports, feature requests, questions, etc. you should create an issue on the <GitHub Issue Tracker|https://github.com/nnutter/mojo-pgx-cursor/issues> for this module.

REFERENCES

#93266 for DBD-Pg: DBD::Pg to set the fetch size

#19488 for DBD-Pg: Support of cursor concept

LICENSE

Copyright (C) Nathaniel Nutter.

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

AUTHOR

Nathaniel Nutter nnutter@cpan.org

SEE ALSO

DBD::Pg, Mojo::Pg, Mojo::PgX::Cursor::Cursor, Mojo::PgX::Cursor::Database, Mojo::PgX::Cursor::Results