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DBD::Gofer::Transport::corostream - Async DBD::Gofer stream transport using Coro and AnyEvent
Contents
Appendix
Example code:
#!perl
use strict;
use warnings;
use Time::HiRes qw(time);
BEGIN { $ENV{PERL_ANYEVENT_STRICT} = 1; $ENV{PERL_ANYEVENT_VERBOSE} = 1; }
use AnyEvent;
BEGIN { $ENV{DBI_TRACE} = 0; $ENV{DBI_GOFER_TRACE} = 0; $ENV{DBD_GOFER_TRACE} = 0; };
use DBI;
$ENV{DBI_AUTOPROXY} = 'dbi:Gofer:transport=corostream';
my $ticker = AnyEvent->timer( after => 0, interval => 0.1, cb => sub {
warn sprintf "-tick- %.2f\n", time
} );
warn "connecting...\n";
my $dbh = DBI->connect("dbi:NullP:");
warn "...connected\n";
for (1..3) {
warn "entering DBI...\n";
$dbh->do("sleep 0.3"); # pseudo-sql understood by the DBD::NullP driver
warn "...returned\n";
}
warn "done.";
Example output:
$ perl corogofer.pl
connecting...
-tick- 1293631437.14
-tick- 1293631437.14
...connected
entering DBI...
-tick- 1293631437.25
-tick- 1293631437.35
-tick- 1293631437.45
-tick- 1293631437.55
...returned
entering DBI...
-tick- 1293631437.66
-tick- 1293631437.76
-tick- 1293631437.86
...returned
entering DBI...
-tick- 1293631437.96
-tick- 1293631438.06
-tick- 1293631438.16
...returned
done. at corogofer.pl line 39.
You can see that the timer callback is firing while the code 'waits' inside the do() method for the
response from the database. Normally that would block.
perl v5.40.0 2025-02-01 DBD::Gofer::Transport::corostream(3pm)
Description
The BIGWIN from using Coro is that it enables the use of existing DBI frameworks like DBIx::Class.
Known Issues And Limitations
- Uses Coro::Select so alters CORE::select globally
Parent class probably needs refactoring to enable a more encapsulated approach.
- Doesn't prevent multiple concurrent requests
Probably just needs a per-connection semaphore
- Coro has many caveats. Caveat emptor.
Licence And Copyright
Copyright (c) 2010, Tim Bunce, Ireland. All rights reserved.
This module is free software; you can redistribute it and/or modify it under the same terms as Perl
itself. See perlartistic.
Name
DBD::Gofer::Transport::corostream - Async DBD::Gofer stream transport using Coro and AnyEvent
See Also
DBD::Gofer::Transport::stream
DBD::Gofer
Status
THIS IS CURRENTLY JUST A PROOF-OF-CONCEPT IMPLEMENTATION FOR EXPERIMENTATION.
Please note that I have no plans to develop this code further myself. I'd very much welcome
contributions. Interested? Let me know!
Synopsis
DBI_AUTOPROXY="dbi:Gofer:transport=corostream" perl some-perl-script-using-dbi.pl
or
$dsn = ...; # the DSN for the driver and database you want to use
$dbh = DBI->connect("dbi:Gofer:transport=corostream;dsn=$dsn", ...);
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