Good question - I have always hacked something with fork in the past but it just seemed so simple with Thread::Queue and threads. I've never needed much IPC in the past.
It looks like this could be a better option: http://search.cpan.org/~aristotle/Proc-Fork-0.802/lib/Proc/Fork.pm#Multi-child_example (thanks also to Dominic for the same warning re: threads) On Sun, Jul 28, 2013 at 9:13 PM, Dave Hodgkinson <daveh...@gmail.com> wrote: > Threads? Now you have two problems. Why not processes? > > Sent from my iPhone > > On 28 Jul 2013, at 20:07, Bob MacCallum <uncool...@gmail.com> wrote: > > > Sorry for the Perl question, but I'm a bit out of my depth... > > > > I have a Dancer app providing a web service, and I have another script > > using the same Dancer config file and db schema (e.g. "use Dancer > > qw/:script/"). This script watches the database (for changes made by the > > web app) and does the "heavy lifting". Now I want to parallelise the > heavy > > lifting with threads and it seems from the core dump and googling that > > DBD::Pg is not thread safe (see the few lines of debugger output below). > > > > That's fine - I am happy to run only non-database code in my "worker > > threads". The trouble is that even if I do this, I think the > > threads->create is threading the Dancer globals which include postgres > > schema connections. > > > > I tried a few "no My::Schema; no DBD::Pg; no Dancer ..." declarations in > > the block with the threads->create - but that didn't seem to help. > > > > Does anyone know how I can use thread-safe and thread-unsafe code in the > > same script? I think I just need to make a block where none of the > > Dancer/database stuff is in scope? > > > > I thought Thread::Isolate might help, but it hangs on the first test > during > > the install. It's dated 2005. > > > > thanks! > > Bob. > > > > > > > > Reading symbols from > > .../perl5/x86_64-linux-thread-multi/auto/DBD/Pg/Pg.so...done. > > Loaded symbols for .../perl5/x86_64-linux-thread-multi/auto/DBD/Pg/Pg.so > > Reading symbols from > > /usr/local/pgsql_dir/postgresql-8.4.7/lib/libpq.so.5...(no debugging > > symbols found)...done. > > Loaded symbols for /usr/local/pgsql_dir/postgresql-8.4.7/lib/libpq.so.5 > > Core was generated by `perl bin/maintain_populations-threaded.pl'. > > Program terminated with signal 11, Segmentation fault. > > #0 0x00007f9de39e923e in PerlIOEncode_getarg () from > > > /usr/lib/perl5/5.12.3/x86_64-linux-thread-multi/auto/PerlIO/encoding/encoding.so > >