Re: Speed up Clog Access by increasing CLOG buffers

On Fri, Dec 18, 2015 at 9:58 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> On Fri, Dec 18, 2015 at 1:16 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
wrote:
>
> >> Some random comments:
> >>
> >> - TransactionGroupUpdateXidStatus could do just as well without
> >> add_proc_to_group. You could just say if (group_no >= NUM_GROUPS)
> >> break; instead. Also, I think you could combine the two if statements
> >> inside the loop. if (nextidx != INVALID_PGPROCNO &&
> >> ProcGlobal->allProcs[nextidx].clogPage == proc->clogPage) break; or
> >> something like that.
> >>

Changed as per suggestion.

> >> - memberXid and memberXidstatus are terrible names. Member of what?
> >
> > How about changing them to clogGroupMemberXid and
> > clogGroupMemberXidStatus?
>
> What we've currently got for group XID clearing for the ProcArray is
> clearXid, nextClearXidElem, and backendLatestXid. We should try to
> make these things consistent. Maybe rename those to
> procArrayGroupMember, procArrayGroupNext, procArrayGroupXid
>

Here procArrayGroupXid sounds like Xid at group level, how about
procArrayGroupMemberXid?
Find the patch with renamed variables for PGProc
(rename_pgproc_variables_v1.patch) attached with mail.

> and then
> start all of these identifiers with clogGroup as you propose.
>

I have changed them accordingly in the attached patch
(group_update_clog_v4.patch) and addressed other comments given by
you.

With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com