coro::select(3pm) [debian man page]

Select(3pm)						User Contributed Perl Documentation					       Select(3pm)

NAME

       Coro::Select - a (slow but coro-aware) replacement for CORE::select

SYNOPSIS

	use Coro::Select;	   # replace select globally (be careful, see below)
	use Core::Select 'select'; # only in this module
	use Coro::Select ();	   # use Coro::Select::select

DESCRIPTION

       This module tries to create a fully working replacement for perl's "select" built-in, using "AnyEvent" watchers to do the job, so other
       threads can run in parallel to any select user. As many libraries that only have a blocking API do not use global variables and often use
       select (or IO::Select), this effectively makes most such libraries "somewhat" non-blocking w.r.t. other threads.

       This implementation works fastest when only very few bits are set in the fd set(s).

       To be effective globally, this module must be "use"'d before any other module that uses "select", so it should generally be the first
       module "use"'d in the main program. Note that overriding "select" globally might actually cause problems, as some "AnyEvent" backends use
       "select" themselves, and asking AnyEvent to use Coro::Select, which in turn asks AnyEvent will not quite work.

       You can also invoke it from the commandline as "perl -MCoro::Select".

       To override select only for a single module (e.g. "Net::DBus::Reactor"), use a code fragment like this to load it:

	  {
	     package Net::DBus::Reactor;
	     use Coro::Select qw(select);
	     use Net::DBus::Reactor;
	  }

       Some modules (notably POE::Loop::Select) directly call "CORE::select". For these modules, we need to patch the opcode table by sandwiching
       it between calls to "Coro::Select::patch_pp_sselect" and "Coro::Select::unpatch_pp_sselect":

	BEGIN {
	   use Coro::Select ();
	   Coro::Select::patch_pp_sselect;
	   require evil_poe_module_using_CORE::SELECT;
	   Coro::Select::unpatch_pp_sselect;
	}

BUGS

       For performance reasons, Coro::Select's select function might not properly detect bad file descriptors (but relying on EBADF is inherently
       non-portable).

SEE ALSO

       Coro::LWP.

AUTHOR

	Marc Lehmann <schmorp@schmorp.de>
	http://home.schmorp.de/

perl v5.14.2							    2012-04-13							       Select(3pm)

DBD::Gofer::Transport::corostream(3pm)			User Contributed Perl Documentation		    DBD::Gofer::Transport::corostream(3pm)

NAME

       DBD::Gofer::Transport::corostream - Async DBD::Gofer stream transport using Coro and AnyEvent

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", ...);

DESCRIPTION

       The BIG WIN 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.

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!

AUTHOR

       Tim Bunce, <http://www.tim.bunce.name>

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.

SEE ALSO

       DBD::Gofer::Transport::stream

       DBD::Gofer

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
", time
	   } );

	   warn "connecting...
";
	   my $dbh = DBI->connect("dbi:NullP:");
	   warn "...connected
";

	   for (1..3) {
	       warn "entering DBI...
";
	       $dbh->do("sleep 0.3"); # pseudo-sql understood by the DBD::NullP driver
	       warn "...returned
";
	   }

	   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 v5.12.3							    2010-12-29				    DBD::Gofer::Transport::corostream(3pm)