[syslog-ng] Regex subpattern macros [1.9.9]

[Mel Collins]

 Hi,
 I'm using syslog-ng's match filter to extract parts of messages for use in 
parts of the destination; specifically in the log file name and template 
sections.
 The messages sent to syslog-ng for this purpose are all of the format: 
"<filename> <message>" (plus whatever sl-ng prepends).

 .conf extract:
filter f_logsplitter { match ("^.*?: ([^ ]*) (.*)$"); };
destination d_logfiles {
	file ("/our/logs/$1"
		template ("$2\n")
		...
etc.

 Eg. For the message "root: foo/bar.log some text", the log 
file /our/logs/foo/bar.log gets "some text" appended to it.

 Now this seems to work fine for low traffic, but if I send 10k messages in a 
tight loop - either locally or remotely via TCP - $2 contains the wrong 
string for many/most of them, eg:
07/03/2006 16:56:34 SEEK #3
07/03/2006 16:56:35 SEEK #3
07/03/2006 16:56:35 SEEK #3
07/03/2006 16:56:35 SEEK #7
07/03/2006 16:56:35 SEEK #7
07/03/2006 16:56:35 SEEK #7
07/03/2006 16:56:35 SEEK #7
07/03/2006 16:56:35 SEEK #8
07/03/2006 16:56:35 SEEK #11
07/03/2006 16:56:35 SEEK #11
07/03/2006 16:56:35 SEEK #11
 ...where the #number should be consecutive.
 If I use $MSGONLY, or such, the correct message line is used.

 It seems to me like the subpattern macros - $1, $2, etc - aren't maintained 
on a per-message basis, but are global..?
 Given that they aren't documented (that I can find), are the presence of $1, 
etc. an unintended side-effect of using a regex? Am I doing something I 
shouldn't by using them?
 Or did I find me a bug? ;o)

 Takk,
 - Mel C