Weirdness in JVM usage with Gemstone

[wayner]

Currently I have three extenders connected to my server and the SageUI on the server. My JVM usage (according to the monitor in Gemstone) is 680MB out of a total of 1038MB. That's pretty good.

But other times I have seen JVM usage with no extenders connected - just the UI on the server.

Any idea why that would be? In the past I would generally see a very strong correlation between the number of extenders connected and JVM usage and 4-5 connectors would crash the system. I have 8 extenders in my house (one more in the pool cabana from May-Sep) so this is an issue for me. If I don't have most of these extenders on UPSes then a power flash would cause a Sage crash as all of the extenders would restart and try to connect to the server (which has always had a UPS).

[jusjoken]

The UI on the server also takes memory from the same JVM so it will still indicate use if it is open. A separate client running on another PC will use it's own JVM and not the servers.

Sage/Java also does not automatically cleanup (garbage collect) memory unless it feels it needs to. So even if extenders are no longer connected the memory will still show in the JVM counts....until needed and then it will clean up and make space available.

As mentioned before, you can force the cleanup from the Main MEnu of Gemstone by pressing DELETE too.

k

[wayner]

Originally Posted by jusjoken

As mentioned before, you can force the cleanup from the Main MEnu of Gemstone by pressing DELETE too.

Is this an addition to Gemstone or is it available in the stock UI?

What is the Java command to do this? Maybe I should run a cron job in SJQ to force a cleanup a couple of times a day?

[phelme]

Originally Posted by jusjoken

As mentioned before, you can force the cleanup from the Main MEnu of Gemstone by pressing DELETE too.

But that's never enough is it? Once one starts to bump up against the limit, there's no choice but to restart the service because everything is a slog. At least that's my experience with the plug-in's I have added.

The one big downside of SageTV & Java IMO.

[wayner]

I am not an expert on these things but someone mentioned in a post that if Sage had ever been rewritten in 64 bit code then they could have used the 64 bit JVM and used a lot more than 1GB for the JVM, solving this problem if you had enough RAM in your PC.

[phelme]

Originally Posted by wayner

I am not an expert on these things but someone mentioned in a post that if Sage had ever been rewritten in 64 bit code then they could have used the 64 bit JVM and used a lot more than 1GB for the JVM, solving this problem if you had enough RAM in your PC.

I assume they've solved this by now in Google Fiber TV.

[wayner]

Maybe, maybe not. It may depend on how many clients they expect you to have running with Google Fiber. Hopefully we get a better idea when Brent finally gets his Google Fiber install.

How many extenders do you have? I would think that this isn't as much of an issue for people with 1-2 extenders, as it is for someone like me with 8-9 and it is not unusual for 5-6 to be used in any 24 hour period.

[jusjoken]

Originally Posted by wayner

Is this an addition to Gemstone or is it available in the stock UI?

What is the Java command to do this? Maybe I should run a cron job in SJQ to force a cleanup a couple of times a day?

I added this in the gemstone code just for debugging purposes.


k

[wayner]

Is it fairly simple Java code to do a cleanup? If so can you please post it. Thanks.

[phelme]

Originally Posted by wayner

How many extenders do you have? I would think that this isn't as much of an issue for people with 1-2 extenders, as it is for someone like me with 8-9 and it is not unusual for 5-6 to be used in any 24 hour period.

I only have a couple extenders, but if I use any UI that involves cached imagery (Gemstone, simple Phoenix on default or Phoenix 2) my heap minimum slowly grows within a few days to my limit of 1280 and I have to restart the service.

I have other plug-ins as well (SJQ/SJQ UI, enable favorites, CMT, commercial detector & UI, comskip etc.), but it is always the enabling of fanart caching plug-ins that cause the memory creep for me.

[jusjoken]

Originally Posted by wayner

Is it fairly simple Java code to do a cleanup? If so can you please post it. Thanks.

Sure....

java.lang.System.gc()

When you press Delete....I call that twice as I find it helps to clean it up quicker.

k

[jusjoken]

Originally Posted by phelme

I only have a couple extenders, but if I use any UI that involves cached imagery (Gemstone, simple Phoenix on default or Phoenix 2) my heap minimum slowly grows within a few days to my limit of 1280 and I have to restart the service.

I have other plug-ins as well (SJQ/SJQ UI, enable favorites, CMT, commercial detector & UI, comskip etc.), but it is always the enabling of fanart caching plug-ins that cause the memory creep for me.

My experience with the latest Gemstone (but it's not an impartial opinion) running 2 extenders full time has been that the memory stays generally below 500MB and each extender adds approx 200MB. I NEVER reboot my server to cleanup JVM.

Certainly older Diamond and Gemstone versions did "leak" JVM but I do find this one to be relatively good at keeping it cleaned up.

YMMV.

k

[wayner]

My issue is likely that I have so many and that each one doesn't cleanup when it goes into standby mode.

[wayner]

Originally Posted by jusjoken

Sure....

java.lang.System.gc()

When you press Delete....I call that twice as I find it helps to clean it up quicker.

k

Do you pause a few seconds between the cleanup calls?

[jusjoken]

No I do not.

k