Re: caching questions
On Tue, 22 Jul 2003 13:05:00 +0300, Stas Bekman wrote: > Peter Haworth wrote: > > Cache::Mmap (which I wrote) isn't threadsafe, but should work OK in a > > forking MPM. If anyone wants to contribute code to make it threadsafe > > (preferably without impacting single-threaded performance too much), > > I'll be very grateful. I'd do it myself, but I've never used threads, so > > I'm bound to get it wrong. > > I haven't looked at the module's implementation, but if you have a C-level > thread-safety issues, you may consider using libapr which provides a > thread-safe mmap API. No, it's perl-level stuff at the point that matters. Currently, it uses fine grained file locking to prevent concurrent accesses from other processes, but as far as I understand it, this won't prevent concurrent accesses from other threads in the same process. -- Peter Haworth [EMAIL PROTECTED] "Do you expect me to implement it?" "No, Mister Schwern, I expect you to DIE!" -- Michael G Schwern in p5p
Re: caching questions
On Tue, 2003-07-22 at 02:13, Tom Schindl wrote: > Sorry to step in here, but could I use any of the caching modules you > mentionned in mod_perl2? I can't vouch for the thread safety of these modules, but all of them should work in prefork mode. - Perrin
Re: caching questions
Peter Haworth wrote: On 22 Jul 2003 08:13:43 +0200, Tom Schindl wrote: Am Mon, 2003-07-21 um 21.45 schrieb Perrin Harkins: On Sun, 2003-07-20 at 15:47, Patrick Galbraith wrote: I know there's IPC, and also memcached. I've used IPC::Shareable before, but don't know if that's the route I'd wanna go. It's not. IPC::Shareable is very slow. If you want to share data, use Cache::FileCache, Cache::Mmap, MLDBM::Sync, or IPC::MM. Sorry to step in here, but could I use any of the caching modules you mentionned in mod_perl2? Cache::Mmap (which I wrote) isn't threadsafe, but should work OK in a forking MPM. If anyone wants to contribute code to make it threadsafe (preferably without impacting single-threaded performance too much), I'll be very grateful. I'd do it myself, but I've never used threads, so I'm bound to get it wrong. I haven't looked at the module's implementation, but if you have a C-level thread-safety issues, you may consider using libapr which provides a thread-safe mmap API. __ Stas BekmanJAm_pH --> Just Another mod_perl Hacker http://stason.org/ mod_perl Guide ---> http://perl.apache.org mailto:[EMAIL PROTECTED] http://use.perl.org http://apacheweek.com http://modperlbook.org http://apache.org http://ticketmaster.com
Re: caching questions
On 22 Jul 2003 08:13:43 +0200, Tom Schindl wrote: > Am Mon, 2003-07-21 um 21.45 schrieb Perrin Harkins: > > On Sun, 2003-07-20 at 15:47, Patrick Galbraith wrote: > > > I know there's IPC, and also memcached. I've used IPC::Shareable > > > before, but don't know if that's the route I'd wanna go. > > > > It's not. IPC::Shareable is very slow. If you want to share data, use > > Cache::FileCache, Cache::Mmap, MLDBM::Sync, or IPC::MM. > > Sorry to step in here, but could I use any of the caching modules you > mentionned in mod_perl2? Cache::Mmap (which I wrote) isn't threadsafe, but should work OK in a forking MPM. If anyone wants to contribute code to make it threadsafe (preferably without impacting single-threaded performance too much), I'll be very grateful. I'd do it myself, but I've never used threads, so I'm bound to get it wrong. -- Peter Haworth [EMAIL PROTECTED] "[That sentence] occupied the table running through the middle of the middle room in a half-way house. It was so equidistant that it managed to find a patch of gravitic stability, a Lagrange of Reason, within which it set up a giant tubular space station of the type that NASA were hoping to build by 2010." -- Ashley Pomeroy
Re: caching questions
Sorry to step in here, but could I use any of the caching modules you mentionned in mod_perl2? thx tom Am Mon, 2003-07-21 um 21.45 schrieb Perrin Harkins: > On Sun, 2003-07-20 at 15:47, Patrick Galbraith wrote: > > One thing that my code does is check to see if it's cache has been > > updated to the db, which I wish I could really have some sort of cache > > that's in one place in memory (as opposed to each child process). > > Well, you can't, unless you use threads. > > > I know there's IPC, and also memcached. I've used IPC::Shareable before, > > but don't know if that's the route I'd wanna go. > > It's not. IPC::Shareable is very slow. If you want to share data, use > Cache::FileCache, Cache::Mmap, MLDBM::Sync, or IPC::MM. > > > Has anyone implemented a good caching system that sets up a global cache > > that you don't have to check constantly because you happen to have been > > served out by a child that doesn't have the latest cache from DB? One > > single memory object? > > The systems I listed above all use a shared cache that will have the > same data regardless of which process accesses it. > > - Perrin >
Re: caching questions
On Sun, 2003-07-20 at 15:47, Patrick Galbraith wrote: > One thing that my code does is check to see if it's cache has been > updated to the db, which I wish I could really have some sort of cache > that's in one place in memory (as opposed to each child process). Well, you can't, unless you use threads. > I know there's IPC, and also memcached. I've used IPC::Shareable before, > but don't know if that's the route I'd wanna go. It's not. IPC::Shareable is very slow. If you want to share data, use Cache::FileCache, Cache::Mmap, MLDBM::Sync, or IPC::MM. > Has anyone implemented a good caching system that sets up a global cache > that you don't have to check constantly because you happen to have been > served out by a child that doesn't have the latest cache from DB? One > single memory object? The systems I listed above all use a shared cache that will have the same data regardless of which process accesses it. - Perrin
caching questions
Today I just looked at Apache::Session, and just realised I spent the last couple weeks coding what it does, more or less. I'm not sure If I should use what I wrote, or it. One thing that my code does is check to see if it's cache has been updated to the db, which I wish I could really have some sort of cache that's in one place in memory (as opposed to each child process). I know there's IPC, and also memcached. I've used IPC::Shareable before, but don't know if that's the route I'd wanna go. Has anyone implemented a good caching system that sets up a global cache that you don't have to check constantly because you happen to have been served out by a child that doesn't have the latest cache from DB? One single memory object? I hope what I'm asking makes sense ;) thanks much... -- -- Patrick Galbraith Senior Software Developer [EMAIL PROTECTED] [EMAIL PROTECTED] [EMAIL PROTECTED] 206.719.2461
