Note about H2 and GC

[Holger Hoffstaette]

Hi,

while poking around in the TC sources I found the H2 statistics store.
Just wanted to note that H2 not only has hardcoded busy-wait loops
(causing constant thread wakeups, though with interspersed waits) and
other questionable programming practices, but also explicitly calls
System.gc() which will of course cause unexpected performance degradation
unless explicitly disabled through -XX:+DisableExplicitGC. Just thought
I'd mention this since I didn't find this flag in the standard server
scripts and TC often runs with large heaps.

hope this helps.
Holger


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[teck-terracotta]

Thanks for the tip Holger! We'll have a look

> -----Original Message-----
> From: tc-dev-bounces@... [mailto:tc-dev-
> bounces@...] On Behalf Of Holger Hoffstaette
> Sent: Thursday, October 09, 2008 10:22 AM
> To: tc-dev@...
> Subject: [tc-dev] Note about H2 and GC
>
> Hi,
>
> while poking around in the TC sources I found the H2 statistics store.
> Just wanted to note that H2 not only has hardcoded busy-wait loops
> (causing constant thread wakeups, though with interspersed waits) and
> other questionable programming practices, but also explicitly calls
> System.gc() which will of course cause unexpected performance

degradation

> unless explicitly disabled through -XX:+DisableExplicitGC. Just thought
> I'd mention this since I didn't find this flag in the standard server
> scripts and TC often runs with large heaps.
>
> hope this helps.
> Holger
>
>
> _______________________________________________
> tc-dev mailing list
> tc-dev@...
> http://lists.terracotta.org/mailman/listinfo/tc-dev

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