Re: Reduce ProcArrayLock contention

On Wed, Aug 5, 2015 at 10:59 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> On Tue, Aug 4, 2015 at 8:59 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>>
>> I'm not entirely happy with the name "nextClearXidElem" but apart from
>> that I'm fairly happy with this version. We should probably test it
>> to make sure I haven't broken anything;
>
>
> I have verified the patch and it is fine. I have tested it via manual
> tests; for long pgbench tests, results are quite similar to previous
> versions of patch.
>
> Few changes, I have made in patch:
>
> 1.
>
> +static void
>
> +ProcArrayGroupClearXid(PGPROC *proc, TransactionId latestXid)
>
> +{
>
> + volatile PROC_HDR *procglobal = ProcGlobal;
>
> + uint32 nextidx;
>
> + uint32 wakeidx;
>
> + int extraWaits = -1;
>
> +
>
> + /* We should definitely have an XID to clear. */
>
> + Assert(TransactionIdIsValid(pgxact->xid));
>
>
>
> Here Assert is using pgxact which is wrong.
>
> 2. Made ProcArrayEndTransactionInternal as inline function as
> suggested by you.

OK, committed.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company