On Fri, Jun 10, 2011 at 04:21:59PM +0200, Marc Cousin wrote: > On 02/11/2010 17:17, heasley wrote: > > The following bug has been logged online: > > > > Bug reference: 5741 > > Logged by: heasley > > Email address: h...@shrubbery.net > > PostgreSQL version: 8.4 > > Operating system: solaris > > Description: syslog line length > > Details: > > > > * Max string length to send to syslog(). Note that this doesn't count the > > * sequence-number prefix we add, and of course it doesn't count the prefix > > * added by syslog itself. On many implementations it seems that the > > hard > > * limit is approximately 2K bytes including both those prefixes. > > */ > > #ifndef PG_SYSLOG_LIMIT > > #define PG_SYSLOG_LIMIT 1024 > > #endif > > > > solaris' syslogd limits the line length to 1024, with a > > FQDN and it's silly "msg ID" quite a bit is dropped by > > syslogd. > > > I've been having the exact same problem with CentOS 5.5 these days (and > a customer's Red Hat 5.4). > > This same problem occurs with sysklogd, which has a > #define MAXLINE 1024 /* maximum line length */
A PG_SYSLOG_LIMIT value that loses data to truncation on nearly every default GNU/Linux installation makes for a poor default. It seems we raised it from 128 to 1024 for version 8.4, on performance grounds: http://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=6b7eebc05e3bfd86757f5aa1f05bca463e92d7db How about 896? I reach that figure based on 1024 as a reasonable limit for the total syslog line, including prefix, and these estimates for the prefix parts: 25 - fixed-length content 16 - syslog_ident [default is "postgres"] 10 - pid 32 - hostname [certainly not a limit, but frequently adequate] 10 - sequence number [ditto] 3 - chunk number [ditto] 32 - facility/priority/message ID added by some syslog implementations = 128 Perhaps, though, the default should be outright conservative, like 512. We could also have a compile-time fixed overhead and factor in actual lengths of parts we know at runtime, but that smells like overkill. Opinions? -- Noah Misch http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
