Re: Reduce ProcArrayLock contention

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.

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