Bruce Momjian wrote:
>
> > Please give examples of true RDBMS SQL servers which return rows before
> > completing the database scan.
>
> My comments exactly. I know of no such SQL engine. Now, there are some
> which will keep the RESULTS on the server, and only return them
> one-by-one. That may be a speed savings. Also, if your query uses
> ORDER BY, I am in the process of improving the performance of that code.
Another possibility is to multi-thread the pqlib front end, so it can
start returning rows while rows are still coming from the backend. For
fast machines or for a few rows, there would be no performance
improvement, but for really big queries you might notice a significant
difference.
There have been several threads of discussion regarding multi-threading
in the backend. IMHO, many of the performance gains people are hoping to
get from that would be addressed by multi-threading frontends instead.
For example, a web server version of a frontend could run as a daemon
and connect to several database sessions, then service web requests from
those permanent sessions.
- Tom
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