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pgsql: Improve detection of child-process SIGPIPE failures. 3+ messages / 1 participants [nested] [flat]
* pgsql: Improve detection of child-process SIGPIPE failures. @ 2018-12-16 19:52 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 3+ messages in thread From: Tom Lane @ 2018-12-16 19:52 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Improve detection of child-process SIGPIPE failures. Commit ffa4cbd62 added logic to detect SIGPIPE failure of a COPY child process, but it only worked correctly if the SIGPIPE occurred in the immediate child process. Depending on the shell in use and the complexity of the shell command string, we might instead get back an exit code of 128 + SIGPIPE, representing a shell error exit reporting SIGPIPE in the child process. We could just hack up ClosePipeToProgram() to add the extra case, but it seems like this is a fairly general issue deserving a more general and better-documented solution. I chose to add a couple of functions in src/common/wait_error.c, which is a natural place to know about wait-result encodings, that will test for either a specific child-process signal type or any child-process signal failure. Then, adjust other places that were doing ad-hoc tests of this type to use the common functions. In RestoreArchivedFile, this fixes a race condition affecting whether the process will report an error or just silently proc_exit(1): before, that depended on whether the intermediate shell got SIGTERM'd itself or reported a child process failing on SIGTERM. Like the previous patch, back-patch to v10; we could go further but there seems no real need to. Per report from Erik Rijkers. Discussion: https://postgr.es/m/f3683f87ab1701bea5d86a7742b22432@xs4all.nl Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/ade2d61ed09c11a3d374a98c66c8a05cb82a0069 Modified Files -------------- src/backend/access/transam/xlogarchive.c | 20 ++++----------- src/backend/commands/copy.c | 3 +-- src/backend/postmaster/pgarch.c | 10 +++----- src/common/wait_error.c | 43 ++++++++++++++++++++++++++++++++ src/include/port.h | 2 ++ 5 files changed, 55 insertions(+), 23 deletions(-) ^ permalink raw reply [nested|flat] 3+ messages in thread
* pgsql: Improve detection of child-process SIGPIPE failures. @ 2018-12-16 19:52 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 3+ messages in thread From: Tom Lane @ 2018-12-16 19:52 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Improve detection of child-process SIGPIPE failures. Commit ffa4cbd62 added logic to detect SIGPIPE failure of a COPY child process, but it only worked correctly if the SIGPIPE occurred in the immediate child process. Depending on the shell in use and the complexity of the shell command string, we might instead get back an exit code of 128 + SIGPIPE, representing a shell error exit reporting SIGPIPE in the child process. We could just hack up ClosePipeToProgram() to add the extra case, but it seems like this is a fairly general issue deserving a more general and better-documented solution. I chose to add a couple of functions in src/common/wait_error.c, which is a natural place to know about wait-result encodings, that will test for either a specific child-process signal type or any child-process signal failure. Then, adjust other places that were doing ad-hoc tests of this type to use the common functions. In RestoreArchivedFile, this fixes a race condition affecting whether the process will report an error or just silently proc_exit(1): before, that depended on whether the intermediate shell got SIGTERM'd itself or reported a child process failing on SIGTERM. Like the previous patch, back-patch to v10; we could go further but there seems no real need to. Per report from Erik Rijkers. Discussion: https://postgr.es/m/f3683f87ab1701bea5d86a7742b22432@xs4all.nl Branch ------ REL_11_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/b1894a6076f36a20338e0c3b0eb73a250ea2e47e Modified Files -------------- src/backend/access/transam/xlogarchive.c | 20 ++++----------- src/backend/commands/copy.c | 3 +-- src/backend/postmaster/pgarch.c | 10 +++----- src/common/wait_error.c | 43 ++++++++++++++++++++++++++++++++ src/include/port.h | 2 ++ 5 files changed, 55 insertions(+), 23 deletions(-) ^ permalink raw reply [nested|flat] 3+ messages in thread
* pgsql: Improve detection of child-process SIGPIPE failures. @ 2018-12-16 19:52 Tom Lane <tgl@sss.pgh.pa.us> 0 siblings, 0 replies; 3+ messages in thread From: Tom Lane @ 2018-12-16 19:52 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Improve detection of child-process SIGPIPE failures. Commit ffa4cbd62 added logic to detect SIGPIPE failure of a COPY child process, but it only worked correctly if the SIGPIPE occurred in the immediate child process. Depending on the shell in use and the complexity of the shell command string, we might instead get back an exit code of 128 + SIGPIPE, representing a shell error exit reporting SIGPIPE in the child process. We could just hack up ClosePipeToProgram() to add the extra case, but it seems like this is a fairly general issue deserving a more general and better-documented solution. I chose to add a couple of functions in src/common/wait_error.c, which is a natural place to know about wait-result encodings, that will test for either a specific child-process signal type or any child-process signal failure. Then, adjust other places that were doing ad-hoc tests of this type to use the common functions. In RestoreArchivedFile, this fixes a race condition affecting whether the process will report an error or just silently proc_exit(1): before, that depended on whether the intermediate shell got SIGTERM'd itself or reported a child process failing on SIGTERM. Like the previous patch, back-patch to v10; we could go further but there seems no real need to. Per report from Erik Rijkers. Discussion: https://postgr.es/m/f3683f87ab1701bea5d86a7742b22432@xs4all.nl Branch ------ REL_10_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/34010ac2fa187ce032a7b243c829c7ef5f047e20 Modified Files -------------- src/backend/access/transam/xlogarchive.c | 20 ++++----------- src/backend/commands/copy.c | 3 +-- src/backend/postmaster/pgarch.c | 10 +++----- src/common/wait_error.c | 43 ++++++++++++++++++++++++++++++++ src/include/port.h | 2 ++ 5 files changed, 55 insertions(+), 23 deletions(-) ^ permalink raw reply [nested|flat] 3+ messages in thread
end of thread, other threads:[~2018-12-16 19:52 UTC | newest] Thread overview: 3+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2018-12-16 19:52 pgsql: Improve detection of child-process SIGPIPE failures. Tom Lane <tgl@sss.pgh.pa.us> 2018-12-16 19:52 pgsql: Improve detection of child-process SIGPIPE failures. Tom Lane <tgl@sss.pgh.pa.us> 2018-12-16 19:52 pgsql: Improve detection of child-process SIGPIPE failures. Tom Lane <tgl@sss.pgh.pa.us>
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