Обсуждение: Fix for "q" with psql display paging dumps out of psql
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
Re: Fix for "q" with psql display paging dumps out of psql
От
jseymour@linxnet.com (Jim Seymour)
Дата:
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@linxnet.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 > > ---------------------------(end of broadcast)--------------------------- > TIP 9: the planner will ignore your desire to choose an index scan if your > joining column's datatypes do not match >
jseymour@linxnet.com (Jim Seymour) writes: > I'm kind of wondering if anybody on the dev team noticed this and > what, if anything, they planned to do with it? Can we make it "#ifdef SOLARIS7" somehow? I'm uneager to put a performance penalty on every platform because of an admittedly broken signal implementation on one. Also, you didn't explain what changed between 7.4.2 and 7.4.6 to make this necessary when it wasn't before. regards, tom lane
You will be glad to know that 8.0 will use a different implementation for thread handling of SIGPIPE, though your asynchronous handling of SIGPIPE will still cause problems. --------------------------------------------------------------------------- Jim Seymour wrote: > 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@linxnet.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 > > > > ---------------------------(end of broadcast)--------------------------- > > TIP 9: the planner will ignore your desire to choose an index scan if your > > joining column's datatypes do not match > > > > ---------------------------(end of broadcast)--------------------------- > TIP 9: the planner will ignore your desire to choose an index scan if your > joining column's datatypes do not match > -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Re: Fix for "q" with psql display paging dumps out of psql
От
jseymour@linxnet.com (Jim Seymour)
Дата:
Tom Lane <tgl@sss.pgh.pa.us> wrote: > > jseymour@linxnet.com (Jim Seymour) writes: > > I'm kind of wondering if anybody on the dev team noticed this and > > what, if anything, they planned to do with it? > > Can we make it "#ifdef SOLARIS7" somehow? I'm uneager to put a > performance penalty on every platform because of an admittedly > broken signal implementation on one. I don't have a problem with #ifdef'ing it in/out. But will an extra pqsignal() call at that point would incur an appreciable performance penalty? > > Also, you didn't explain what changed between 7.4.2 and 7.4.6 to > make this necessary when it wasn't before. That would involve extensive slogging though the code, identifying all the changes made between 7.4.2 and who-knows-what-version (the problem exists with 7.4.5, as well) and working-out their impact. Yeah, it's a kludgy fix. I certainly won't be offended if you don't care to address this problem--particularly if you don't care to use that fix. Jim
Re: Fix for "q" with psql display paging dumps out of psql
От
jseymour@linxnet.com (Jim Seymour)
Дата:
Bruce Momjian <pgman@candle.pha.pa.us> wrote: > > > You will be glad to know that 8.0 will use a different implementation > for thread handling of SIGPIPE, though your asynchronous handling of > SIGPIPE will still cause problems. So-noted. Jim