Re: [PATCH] Add SIGCHLD catch to psql

Stephen Frost wrote:
-- Start of PGP signed section.
> Greetings,
>
> Toying around with FETCH_COUNT today, I discovered that it didn't do
> the #1 thing I really wanted to use it for- query large tables without
> having to worry about LIMIT to see the first couple hundred records.
> The reason is simple- psql ignores $PAGER exiting, which means that it
> will happily continue pulling down the entire large table long after
> you've stopped caring, which means you still have to wait forever.
>
> The attached, admittedly quick hack, fixes this by having psql catch
> SIGCHLD's using handle_sigint. I've tested this and it doesn't
> appear to obviously break other cases where we have children (\!, for
> example), since we're not going to be running a database query when
> we're doing those, and if we are, and the child dies, we probably want
> to *stop* anyway, similar to the $PAGER issue.
>
> Another approach that I considered was fixing various things to deal
> cleanly with write's failing to $PAGER (I presume the writes *were*
> failing, since less was in a defunct state, but I didn't actually
> test). This solution was simpler, faster to code and check, and alot
> less invasive (or so it seemed to me at the time).
>
> Anyway, this makes FETCH_COUNT alot more useful, and, in my view, the
> current behaviour of completely ignoring $PAGER exiting is a bug.

Plesae add this to the next commit-fest:

https://commitfest.postgresql.org/action/commitfest_view/inprogress

Thanks.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com