[syslog-ng]Strang behaviour of syslog-ng (and my program)
Antai Ning
aning@jetnet.ca
Thu, 11 Jul 2002 09:49:12 -0400
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Just add a little more info, if I send the first 10 messages a little bit
slower, say delay 10 msec in between, then it doesn't happen.
-----Original Message-----
From: Antai Ning [mailto:aning@jetnet.ca]
Sent: Wednesday, July 10, 2002 1:38 PM
To: 'syslog-ng@lists.balabit.hu'
Subject: [syslog-ng]Strang behaviour of syslog-ng (and my program)
Hi Gurus,
I got some strange phenomemon with syslog-ng. Here is what I'm doing.
I configured syslog-ng to forward certain type of messages to a pipe. (say,
ALERT). I wrote a program in perl to read from the pipe and print them out.
The perl program first try to open the pipe and it'll block at the open
function untill syslog-ng has some messages to write to the pipe. Then the
perl program reads using IO::File can_read() function, with a 5 seconds
timeout. So the function looks like this: $sel->can_read(5). Then I send 10
valid messages to syslog-ng from a remote machine by UDP. To my supprise,
the perl program got only 2 of the 10! Then I send another 1 valid message
to this syslog-ng after 5 minutes, and I got not only this message, but also
the 8 I lost last time!
This happens only for the first 10 messages (which includes the opening of
the pipe). Everything is fine after the first round. It looks like it's
related to the pipe opening and messages get queued somewhere until later
messages trigger the queue to flush.
So what's really happening inside? And is there a solution?
Thanks,
Andy
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<DIV><SPAN class=150044213-11072002><FONT face=Arial color=#0000ff size=2>Just
add a little more info, if I send the first 10 messages a little bit slower, say
delay 10 msec in between, then it doesn't happen. </FONT></SPAN></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> Antai Ning
[mailto:aning@jetnet.ca]<BR><B>Sent:</B> Wednesday, July 10, 2002 1:38
PM<BR><B>To:</B> 'syslog-ng@lists.balabit.hu'<BR><B>Subject:</B>
[syslog-ng]Strang behaviour of syslog-ng (and my program)<BR><BR></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=710041517-10072002>Hi
Gurus,</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=710041517-10072002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=710041517-10072002>I
got some strange phenomemon with syslog-ng. Here is what I'm
doing.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=710041517-10072002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=710041517-10072002>I
configured syslog-ng to forward certain type of messages to a pipe. (say,
ALERT). I wrote a program in perl to read from the pipe and print them
out. The perl program first try to open the pipe and it'll block at the
open function untill syslog-ng has some messages to write to the pipe.
Then the perl program reads using IO::File can_read() function, with
a 5 seconds timeout. So the function looks like this: $sel->can_read(5).
Then I send 10 valid messages to syslog-ng from a remote machine by UDP. To my
supprise, the perl program got only 2 of the 10! Then I send
another 1 valid message to this syslog-ng after 5 minutes, and I got not
only this message, but also the 8 I lost last
time! </SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=710041517-10072002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=710041517-10072002>This
happens only for the first 10 messages (which includes the opening of the
pipe). Everything is fine after the first round. It looks like it's
related to the pipe opening and messages get queued somewhere until later
messages trigger the queue to flush.</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=710041517-10072002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN class=710041517-10072002>So
what's really happening inside? And is there a
solution?</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=710041517-10072002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=710041517-10072002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=710041517-10072002>Thanks,</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=710041517-10072002></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff size=2><SPAN
class=710041517-10072002>Andy </SPAN></FONT></DIV>
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