Re: Fix for "q" with psql display paging dumps out of psql

Hi,

I'm kind of wondering if anybody on the dev team noticed this and
what, if anything, they planned to do with it?

Jim

jseymour(at)linxnet(dot)com (Jim Seymour) wrote:
>
>
> Hi,
>
> Environment:
>
> SunOS 5.7 Generic_106541-29 sun4u sparc SUNW,UltraSPARC-IIi-Engine
> Postgresql-7.4.6
> Build config: --with-java --enable-thread-safety
> gcc version 3.3.1
> less-381
> readline-4.3
>
> $ echo $PAGER
> /usr/local/bin/less
> $ echo $LESS
> -e
>
> I recently upgraded from 7.4.2 to 7.4.6 and ran into an annoying
> problem. Thereafter, most times, "q"uitting out of paged display
> output would dump me straight out of psql if the query result was
> sufficiently large.
>
> A bit of debugging revealed psql receiving a SIGPIPE to be the
> problem.
>
> Building pgsql w/o --enable-thread-safety eliminated the problem.
>
> It looks like the culprit is asynchronous SIGPIPE signals under Solaris
> 7 when using thread-safe libraries. Here's a reference:
> <http://www.lambdacs.com/cpt/FAQ.html#Q339>.
>
> I do not know if Solaris 8 and beyond behave this way. (Apparently
> async SIGPIPE is not POSIX-compliant, so one hopes Sun has fixed this
> broken behaviour.)
>
> Here's a fix that's simple, effective and doesn't hurt anything else:
>
> ------------------------- begin included text --------------------------
> *** src/bin/psql/print.c-orig Wed Nov 17 08:04:47 2004
> --- src/bin/psql/print.c Sat Nov 20 10:43:22 2004
> ***************
> *** 1119,1124 ****
> --- 1119,1128 ----
> {
> pclose(output);
> #ifndef WIN32
> + /* The SIG_IGN is to compensate for broken Solaris 7
> + * (async) SIGPIPE handling with --enable-thread-safety
> + */
> + pqsignal(SIGPIPE, SIG_IGN);
> pqsignal(SIGPIPE, SIG_DFL);
> #endif
> }
> -------------------------- end included text ---------------------------
>
> Thanks to Andrew, over at SuperNews, for the idea.
>
> Regards,
> Jim
>
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