On Sun, 18 Mar 2007, Oleg Pronin wrote:
Hi. I use PostgreSQL database and want to use it's row locking system.
That's why i need to execute statements like this:
SELECT * FROM table WHERE condition FOR UPDATE (FOR SHARE);
I didn't find a nice solution for that.
I would like to use row-locking in some way like that:
$rs->search(
{column => $value},
{
rows => 1,
locking => 'update',
}
);
The only solution i found without copy-pasting code of '_select' and
'_execute' functions of storage is
in my schema:
__PACKAGE__->storage_type('My::Storage');
in my::storage
package My::Storage;
use base qw/DBIx::Class::Storage::DBI::Pg/;
use strict;
our $_LOCKING = 0;
sub _select {
my $self = shift;
$_LOCKING = $_[3]->{locking} eq 'update' ? 1 : 2 if defined
$_[3]->{locking};
$self->SUPER::_select(@_);
}
sub sth {
my ($self, $sql) = @_;
# 3 is the if_active parameter which avoids active sth re-use
if ($_LOCKING) {
$sql .= $_LOCKING == 1 ? ' FOR UPDATE' : ' FOR SHARE';
$_LOCKING = 0;
}
return $self->dbh->prepare_cached($sql, {}, 3);
}
I understand this is ugly.
Is there a better solution?
Seems fairly sane to me. Would you like to work that into a patch for the
Postgres Storage class and add some tests?
Jess
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