question about HPjmeter gc_logs

[Jim Galliher]

Can i concatenate a weeks worth of gc_logs for one tomcat and get data output over a weeks time? I tried taking out the Headers but i still can only view the data in clock view(seconds). I'd like to view it by days.

thanks!

[JZ2]

Hi, I would like some additional information. How are you generating multiple gc log files from one instance of tomcat? You say that you can only view things in clock view. What happens when you try to switch the display to time view?

[Jim Galliher]

i pull the gc_log for monday then the gc_log for tuesday etc...for one tomcat till i have monday thru friday.


And when i have all those files (monday - friday) concatenated I can't seem to get time view. the button is missing.

Thanks!

[JZ2]

Jim,
A few more questions that I should have asked the first time. What version of HPjmeter are you using? Are the gc logs being generated with -Xverbosegc or -Xloggc? I am trying to determine if the gc log that you capture each day contains data that is distinct from the previous day's gc log? When you specify -Xverbosegc at startup time, you get a cumulative log of data. So, if you copy the file each day, the second day's file is still going to contain information from the moment that you started Tomcat. In that case, there is no need to concatenate the files.

[Jim Galliher]

XX:+UseConcMarkSweepGC -XX:+UseParNewGC -Xv
erbosegc:file=$dir/tomcatLB/tomcat1/gc_logs/tomcat1-gc.log"

are the setting we use.

Every night at 3am, we recyle tomcat so the logs would not be cumulative. thanks in advance for your interest.

[JZ2]

When you 'recycle' tomcat, does that mean you stop it and restart it? The gc data contains a timestamp that is relative to the start of the Java program. So, if you stop and restart tomcat, then each day's gc data will start over with a relative time of 0. In that case, concatenating the log files will not be useful.

I ran a test program several times, concatenated the gc files, and removed the extra header lines. I then read the file into the latest version of HPjmeter, and it processed the file. I did receive this message in my terminal window "GC[NNN] started before previous completed" which indicates that the times were starting over again. I did see the button which allows me to switch between date/time and cumulative time in the displays. Note that this button is not present when looking at the Summary or System Detail tabs.