Re: asynchronous execution

Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> wrote:

> The patch got conflicted. This is a new version just rebased to
> the current master. Furtuer amendment will be taken later.

Just one idea that I had while reading the code.

In ExecAsyncEventLoop you iterate estate->es_pending_async, then move the
complete requests to the end and finaly adjust estate->es_num_pending_async so
that the array no longer contains the complete requests. I think the point is
that then you can add new requests to the end of the array.

I wonder if a set (Bitmapset) of incomplete requests would make the code more
efficient. The set would contain position of each incomplete request in
estate->es_num_pending_async (I think it's the myindex field of
PendingAsyncRequest). If ExecAsyncEventLoop used this set to retrieve the
requests subject to ExecAsyncNotify etc, then the compaction of
estate->es_pending_async wouldn't be necessary.

ExecAsyncRequest would use the set to look for space for new requests by
iterating it and trying to find the first gap (which corresponds to completed
request).

And finally, item would be removed from the set at the moment the request
state is being set to ASYNCREQ_COMPLETE.

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Antonin Houska
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