NAME

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

SYNOPSIS

    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 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