#40544 [Asn]: PostgreSQL connection hangs after die()
ID: 40544 Updated by: [EMAIL PROTECTED] Reported By: kees at tweakers dot net Status: Assigned Bug Type: PostgreSQL related Operating System: Linux (Debian) PHP Version: 5.2.1 Assigned To: yohgaki New Comment: 'Rollback on shutdown' is like 'Don't flush buffer before closing file'. I disagree, you need to commit everything explicitly. If you didn't commit the transaction, it should be rolled back. Previous Comments: [2007-04-05 01:28:11] yohgaki at ohgaki dot net And that's something I would call expected, because rollback on shutdown is much safer than commit on shutdown. As I wrote, under normal condition, current code(commit on shutdown) does make more sense than rollback on shutdown because PostgreSQL supports async query. 'Rollback on shutdown' is like 'Don't flush buffer before closing file'. It does not acceptable for most people. (And more efficient if it finish pending query at shutdown, too. If you are curious, take some simple benchmarks) However, under shared environment, it is not acceptable to consume all connection by COPY FROM SDTIN. It is better to have a way to avoid such action. There are 2 options: 1) Leave it alone (and make DoS possible under shared environment) 2) Give administrators a option that cancel current and pending async query. I prefer first option. I'll ask PostgreSQL developer if it's possible to have GRANT option for COPY in the future. [2007-03-09 10:11:12] [EMAIL PROTECTED] By calling PQcanel() before clean up resource, all async query which is not finished yet will be discarded instead of finishing its query. And that's something I would call expected, because rollback on shutdown is much safer than commit on shutdown. I'll add new ini option that enables PQcancel() in list_entry_destructor. Any comments? More INI options? No, thanks. [2007-03-08 04:24:24] yohgaki at ohgaki dot net I didn't look the backtrace carefully. It stops when PQclear() is called on the backtrace, while my PHP 5.2 stopeed at PQgetReuslt(). (Both of them are called when request is shutting down) For at least PHP 5.2, it would be solved by calling PQcanel() when cleaning up resource, but with compatibility issue. By calling PQcanel() before clean up resource, all async query which is not finished yet will be discarded instead of finishing its query. I'll add new ini option that enables PQcancel() in list_entry_destructor. Any comments? [2007-03-07 22:09:55] yohgaki at ohgaki dot net Since COPY is not a actual SQL statement, PostgreSQL waits forever until COPY ends because the input is STDIN. (SQL Statements like SELECT, UPDATE, DELETE, INSERT will be aborted if there is deadlock) Since PQfinish() (Used while shutting down pgsql connections) does not have option to wait certain amount of time to force closing connection, I'm not sure if it is feasible shutting down w/o waiting to finish COPY, etc. It's possible to force close connection manually using internal PGconn strucutre's connection parameter, but there would be portability issues if it use PGconn internal parameters. I'll see if there is I can do about this in feasible manner. [2007-02-19 15:52:58] kees at tweakers dot net tested with the snapshot: [EMAIL PROTECTED]:/usr/src/php5.2-200702191330$ sapi/cli/php test.3.php Starting And now he hangs in a busy wait [ctrl-c] [EMAIL PROTECTED]:/usr/src/php5.2-200702191330$ sapi/cli/php -v PHP 5.2.2-dev (cli) (built: Feb 19 2007 16:49:22) Copyright (c) 1997-2007 The PHP Group Zend Engine v2.2.0, Copyright (c) 1998-2007 Zend Technologies ldd sapi/cli/php libpq.so.5 = /usr/lib/libpq.so.5 (0xa7f3c000) The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/40544 -- Edit this bug report at http://bugs.php.net/?id=40544edit=1
#40544 [Asn]: PostgreSQL connection hangs after die()
ID: 40544 Updated by: [EMAIL PROTECTED] Reported By: kees at tweakers dot net Status: Assigned Bug Type: PostgreSQL related Operating System: Linux (Debian) PHP Version: 5.2.1 Assigned To: yohgaki New Comment: By calling PQcanel() before clean up resource, all async query which is not finished yet will be discarded instead of finishing its query. And that's something I would call expected, because rollback on shutdown is much safer than commit on shutdown. I'll add new ini option that enables PQcancel() in list_entry_destructor. Any comments? More INI options? No, thanks. Previous Comments: [2007-03-08 04:24:24] yohgaki at ohgaki dot net I didn't look the backtrace carefully. It stops when PQclear() is called on the backtrace, while my PHP 5.2 stopeed at PQgetReuslt(). (Both of them are called when request is shutting down) For at least PHP 5.2, it would be solved by calling PQcanel() when cleaning up resource, but with compatibility issue. By calling PQcanel() before clean up resource, all async query which is not finished yet will be discarded instead of finishing its query. I'll add new ini option that enables PQcancel() in list_entry_destructor. Any comments? [2007-03-07 22:09:55] yohgaki at ohgaki dot net Since COPY is not a actual SQL statement, PostgreSQL waits forever until COPY ends because the input is STDIN. (SQL Statements like SELECT, UPDATE, DELETE, INSERT will be aborted if there is deadlock) Since PQfinish() (Used while shutting down pgsql connections) does not have option to wait certain amount of time to force closing connection, I'm not sure if it is feasible shutting down w/o waiting to finish COPY, etc. It's possible to force close connection manually using internal PGconn strucutre's connection parameter, but there would be portability issues if it use PGconn internal parameters. I'll see if there is I can do about this in feasible manner. [2007-02-19 15:52:58] kees at tweakers dot net tested with the snapshot: [EMAIL PROTECTED]:/usr/src/php5.2-200702191330$ sapi/cli/php test.3.php Starting And now he hangs in a busy wait [ctrl-c] [EMAIL PROTECTED]:/usr/src/php5.2-200702191330$ sapi/cli/php -v PHP 5.2.2-dev (cli) (built: Feb 19 2007 16:49:22) Copyright (c) 1997-2007 The PHP Group Zend Engine v2.2.0, Copyright (c) 1998-2007 Zend Technologies ldd sapi/cli/php libpq.so.5 = /usr/lib/libpq.so.5 (0xa7f3c000) [2007-02-19 15:19:10] acm at tweakers dot net Btw, when hanging gdb to the php-process and type 'bt' you get this: #0 0xa7ba88c0 in free () from /lib/tls/libc.so.6 #1 0xa7ec8ea7 in PQclear () from /usr/lib/libpq.so.5 #2 0x08086fc8 in _close_pgsql_link (rsrc=0x81e43ec) at /usr/src/php-4.4.2/ext/pgsql/pgsql.c:277 #3 0x08139fb2 in list_entry_destructor (ptr=0x81e43ec) at /usr/src/php-4.4.2/Zend/zend_list.c:177 #4 0x08137977 in zend_hash_apply_deleter (ht=0x81a49e0, p=0x81e43b4) at /usr/src/php-4.4.2/Zend/zend_hash.c:611 #5 0x08137b97 in zend_hash_graceful_reverse_destroy (ht=0x81a49e0) at /usr/src/php-4.4.2/Zend/zend_hash.c:677 #6 0x0812b9ed in shutdown_executor () at /usr/src/php-4.4.2/Zend/zend_execute_API.c:211 #7 0x08133801 in zend_deactivate () at /usr/src/php-4.4.2/Zend/zend.c:689 #8 0x08107862 in php_request_shutdown (dummy=0x0) at /usr/src/php-4.4.2/main/main.c:999 #9 0x0814ee56 in main (argc=2, argv=0xafb6d114) at /usr/src/php-4.4.2/sapi/cli/php_cli.c:881 [2007-02-19 15:10:06] [EMAIL PROTECTED] Please try using this CVS snapshot: http://snaps.php.net/php5.2-latest.tar.gz For Windows: http://snaps.php.net/win32/php5.2-win32-latest.zip The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at http://bugs.php.net/40544 -- Edit this bug report at http://bugs.php.net/?id=40544edit=1
