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From:Samuel Ziegler Date:February 1 2007 4:39pm
Subject:Re: Unbounded memory growth in 5.0.24/27
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Thanks for the info Dmitri!  I'll probably dig into it at some point,
but I solved my immediate problem by cycling my DB connections before
they get to large, so it's dropped down on my priority list.

Thanks for your help,
  - Sam

On Tue, 2007-01-30 at 12:03 +0300, Dmitri Lenev wrote:
> Hi, Samuel!
> 
> * Samuel Ziegler <mysql@stripped> [07/01/25 20:09]:
> > Thanks for the feedback, Dmitri!  I will try out 5.0.33 first thing this
> > morning.
> > 
> > A couple of questions for you:
> > - I assume that copies of the stored procedures are kept due to the
> > overhead of preparing them for use, but why are the kept on a per
> > connection basis currently?
> 
> Mainly due to historical reasons. At some point it was impossible to use
> objects which were created during parsing of routine's body in any thread/
> connection other than where they were created originally. Therefore each 
> thread/connection had to use its own instance of routine object and so
> per-connection/thread routine caches were required.
> 
> This limitation was removed during implementation of triggers. But we
> didn't implement global routine cache at that time.
> 
> So this is something still to be done.
> 
> > - Is there any reason that each connection can't have an upper limit on
> > the number of stored procedures it keeps around?
> 
> I don't think there is any... Such limit, probably accompanied with some
> policy for retiring routines from cache (e.g. LRU), can be implemented.
> 
> > - Where is the collection of per connection stored procedures
> > internally?  (class/member variable)
> 
> Look at "sp_proc_cache" and "sp_func_cache" members of "THD" class in
> sql/sql_class.h and at "sp_cache" class in sql/sp_cache.cc and .h.
> 
> Best regards,

Thread
Unbounded memory growth in 5.0.24/27Samuel Ziegler25 Jan
  • Re: Unbounded memory growth in 5.0.24/27Dmitri Lenev25 Jan
    • Re: Unbounded memory growth in 5.0.24/27Samuel Ziegler25 Jan
      • Re: Unbounded memory growth in 5.0.24/27Dmitri Lenev30 Jan
        • Re: Unbounded memory growth in 5.0.24/27Samuel Ziegler1 Feb