Re: Announcing Veil - Mailing list pgsql-hackers

I don't see NUM_USER_DEFINED_LWLOCKS defined in 8.0 or 8.1, so what
system do you propose to allow you to set this value?

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Marc Munro wrote:
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> Tom,
> Thanks for your reponse.  Unless I am missing your point, to add more
> locks we require a minor code change to the postgres server.  I am happy
> to submit a patch but this will not help Veil work with existing
> versions of Postgres.  I am aiming for compatibility with 7.4 onward.
> Your views on this would be appreciated.
> 
> Assuming that simply allocating a few extra LWLocks for user-defined
> functions is acceptable, here are some patches:
> 
> --cut---------------
> *** ./src/backend/storage/lmgr/lwlock.c Sat Aug 20 16:26:24 2005
> --- lwlock.c    Wed Oct  5 08:20:31 2005
> ***************
> *** 120,126 ****
>          */
>         numLocks += 2 * NUM_SLRU_BUFFERS;
> 
> !       /* Perhaps create a few more for use by user-defined modules? */
> 
>         return numLocks;
>   }
> --- 120,127 ----
>          */
>         numLocks += 2 * NUM_SLRU_BUFFERS;
> 
> !       /* Create a few more for use by user-defined modules. */
> !       numLocks += NUM_USER_DEFINED_LWLOCKS;
> 
>         return numLocks;
>   }
> --cut---------------
> *** ./src/include/storage/lwlock.h      Sat Aug 20 16:26:34 2005
> --- lwlock.h    Wed Oct  5 08:22:26 2005
> ***************
> *** 53,58 ****
> --- 53,62 ----
>         MaxDynamicLWLock = 1000000000
>   } LWLockId;
>  
> + /*
> +  * Allocate a few LWLocks for user-defined functions.
> +  */
> + #define NUM_USER_DEFINED_LWLOCKS 4
> 
>   typedef enum LWLockMode
>   {
> --cut---------------
> 
> 
> __
> Marc Munro
> 
> On Tue, 2005-10-04 at 22:51 -0400, Tom Lane wrote:
> > Marc Munro <marc@bloodnok.com> writes:
> > > Since I was unable to dynamically assign a LWLock using
> > > LWLockAssign (none available), I have fairly arbitrarily overloaded the
> > > use of existing LWLocks.  When the flames die down perhaps we can
> > > discuss making a small number (one would be enough for me) of LWLocks
> > > available.
> > 
> > Perhaps you missed the comment in NumLWLocks()?
> > 
> >             regards, tom lane
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