Re: trivial refactoring of WaitOnLock - Mailing list pgsql-patches

Yes, reduced one round of counting the length of new_status.

"Russell Smith" <mr-russ@pws.com.au>
> If the problem is speed, then this may be faster.
>
>
> Index: src/backend/storage/lmgr/lock.c
> ===================================================================
> RCS file: /projects/cvsroot/pgsql/src/backend/storage/lmgr/lock.c,v
> retrieving revision 1.147
> diff -c -r1.147 lock.c
> *** src/backend/storage/lmgr/lock.c     1 Mar 2005 21:14:59 -0000
1.147
> --- src/backend/storage/lmgr/lock.c     9 Mar 2005 08:17:33 -0000
> ***************
> *** 1074,1079 ****
> --- 1074,1080 ----
>                    ResourceOwner owner)
>   {
>         LockMethod      lockMethodTable = LockMethods[lockmethodid];
> +       int                len;
>         char       *new_status,
>                            *old_status;
>
> ***************
> *** 1083,1091 ****
>                            locallock->lock, locallock->tag.mode);
>
>         old_status = pstrdup(get_ps_display());
> !       new_status = (char *) palloc(strlen(old_status) + 10);
>         strcpy(new_status, old_status);
> !       strcat(new_status, " waiting");
>         set_ps_display(new_status);
>
>         awaitedLock = locallock;
> --- 1084,1093 ----
>                            locallock->lock, locallock->tag.mode);
>
>         old_status = pstrdup(get_ps_display());
> !       len = strlen(old_status);
> !       new_status = (char *) palloc(len + 9);
>         strcpy(new_status, old_status);
> !       strcpy(&new_status[len], " waiting");
>         set_ps_display(new_status);
>
>         awaitedLock = locallock;
>
>
>
>
>
>
>
>
>
> On Wed, 9 Mar 2005 06:42 pm, Qingqing Zhou wrote:
> > off-by-one is true, but I am not sure if the revised code is faster.
> > sprintf() need the extra job to parse the format. In win32, I am sure it
is
> > much slower.
> >
> > "Neil Conway" <neilc@samurai.com> ????
news:422E3EAC.9000403@samurai.com...
> > > This patch refactors some code in WaitOnLock slightly. The old code
was
> > > slow, and I believe it was off-by-one (it allocates one byte of memory
> > > more than needed).
> > >
> > > Barring any objections I'll apply this to HEAD later today.
> > >
> > > -Neil
> > >
> >
> >
>
> --------------------------------------------------------------------------
--
> > ----
> >
> >
> > > Index: src/backend/storage/lmgr/lock.c
> > > ===================================================================
> > > RCS file: /var/lib/cvs/pgsql/src/backend/storage/lmgr/lock.c,v
> > > retrieving revision 1.147
> > > diff -c -r1.147 lock.c
> > > *** src/backend/storage/lmgr/lock.c 1 Mar 2005 21:14:59 -0000 1.147
> > > --- src/backend/storage/lmgr/lock.c 8 Mar 2005 05:42:06 -0000
> > > ***************
> > > *** 1076,1081 ****
> > > --- 1076,1082 ----
> > >   LockMethod lockMethodTable = LockMethods[lockmethodid];
> > >   char    *new_status,
> > >      *old_status;
> > > + size_t len;
> > >
> > >   Assert(lockmethodid < NumLockMethods);
> > >
> > > ***************
> > > *** 1083,1091 ****
> > >      locallock->lock, locallock->tag.mode);
> > >
> > >   old_status = pstrdup(get_ps_display());
> > > ! new_status = (char *) palloc(strlen(old_status) + 10);
> > > ! strcpy(new_status, old_status);
> > > ! strcat(new_status, " waiting");
> > >   set_ps_display(new_status);
> > >
> > >   awaitedLock = locallock;
> > > --- 1084,1092 ----
> > >      locallock->lock, locallock->tag.mode);
> > >
> > >   old_status = pstrdup(get_ps_display());
> > > ! len = strlen(old_status);
> > > ! new_status = (char *) palloc(len + 8 + 1);
> > > ! sprintf(new_status, "%s waiting", old_status);
> > >   set_ps_display(new_status);
> > >
> > >   awaitedLock = locallock;
> > >
> >
> >
>
> --------------------------------------------------------------------------
--
> > ----
> >
> >
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