Thanks, Tim and Jonathan. The motivator for the question is that I'm looking to recommend upgrades to management in a month or two, e.g. for library versions (DBI, DBD, etc.), Perl versions, and extra libraries to install. These upgrades would be applied to a number of machines so they have to be planned.
I'm not sure what you meant, Tim, when you referred to extensions. Do you mean non-pure-Perl libraries that require compiling C code, such as DBI and most DBDs? If so I can see the sense in the restriction, as usually the library has to be compiled so as to be compatible with the Perl that will be using it. I'm wondering if anyone has benchmarks comparing Perl with threads against Perl without threads. If it's a 2% slowdown (for instance) it wouldn't be such a big deal, but 50% would bother me. -Will BTW My personal take on email layout is that top-quoting is better 90% of the time because people see up front what I have to say uncluttered and can refer to the earlier discussion as needed. I use bottom quoting when I plan to respond point-by-point several times. -----Original Message----- From: Tim Bunce [mailto:[EMAIL PROTECTED] Sent: Friday 07 October 2005 04:39 To: Jonathan Leffler Cc: Rutherdale, Will; List - DBI users Subject: Re: Perl DBI and threads.pm On Thu, Oct 06, 2005 at 07:42:14PM -0700, Jonathan Leffler wrote: > On 10/6/05, Rutherdale, Will <[EMAIL PROTECTED]> wrote: > > > We have some Perl DBI scripts and have been running them on a Perl > > compiled > > with threading disabled. (I.e. perl -V gives ...usethreads=undef...). I > > also have another environment where Perl is compiled with > > usethreads=define > > and have found the threading capabilities useful. (This is the Perl 5.8 > > threads.pm <http://threads.pm> variety.) > > > > My question is this: if I were to upgrade the platform with the threadless > > Perl to a threaded Perl, would this risk reducing stability or reliability > > of the existing Perl DBI applications? > > > > These applications wouldn't be using multithreading, just switching to a > > Perl with threading enabled. > > I don't have the hands on experience, so if someone with such experience > contradicts me, you should probably take their advice over mine. > > My understanding is that a Perl with multi-threading where you do not use > the multithreading should be as stable as a Perl without the multithreading. > However, there's a chance that some modules may not be so happy. OTOH, DBI > shouldn't be one of those modules; it ensures single-tracking through it. > OTOOH, if you aren't using the multi-threading, there still shouldn't be any > problem. I'd only add that a) the two builds aren't binary compatible so you can't just copy extensions between them, and b) perl built with multi-threading enabled is significantly slower. Tim. - - - - - - - Appended by Scientific-Atlanta, Inc. - - - - - - - This e-mail and any attachments may contain information which is confidential, proprietary, privileged or otherwise protected by law. The information is solely intended for the named addressee (or a person responsible for delivering it to the addressee). If you are not the intended recipient of this message, you are not authorized to read, print, retain, copy or disseminate this message or any part of it. If you have received this e-mail in error, please notify the sender immediately by return e-mail and delete it from your computer.
