Another option to consider is to *decrease* the JVM maximum heap size.
This in effect leaves more memory for swapped in mmio pages and
decreases the GC effort, which might increase system performance and
stability.
Regards,
Christoph
Am 15.05.2012 21:38, schrieb Chris Bamford:
Thanks Uwe.
What I'd like to understand is the implications of this on a server which opens
a large number of indexes over a long period. Will this non-heap memory
continue to grow? Will gc be effective at spotting it and releasing it via
references in the heap?
I had an instance yesterday where a server swapped itself to a standstill and
had to be restarted. The load average was through the roof and I am trying to
understand why. One of my recent changes is updating from 2.3 to 3.6, so
naturally I am keen to know the impact of the mmap stuff which is now standard
under the covers.
My server caches indexsearchers and then closes them based on how full the heap
is getting. My worry is that if the bulk of the memory is being allocated
outside the Jvm, how can I make sensible decisions?
Thanks for any pointers / info.
Chris
-----Original Message-----
From: u...@thetaphi.de
To: java-user@lucene.apache.org
Sent: Tue, 15 May 2012 18:10
Subject: RE: Memory question
It mmaps the files into virtual memory if it runs on a 64 bit JVM. Because
of that you see the mmapped CFS files. This is outside Java Heap and is all
*virtual* no RAM is explicitely occupied except the O/S cache.
-----
Uwe Schindler
H.-H.-Meier-Allee 63, D-28213 Bremen
http://www.thetaphi.de
eMail: u...@thetaphi.de
-----Original Message-----
From: Chris Bamford [mailto:chris.bamf...@talktalk.net]
Sent: Tuesday, May 15, 2012 4:47 PM
To: java-user@lucene.apache.org
Subject: Memory question
Hi
Can anyone tell me what happens to the memory when Lucene opens an index?
Is it loaded into the JVM's heap or is it mapped into virtual memory
outside of
it?
I am running on Linux and if I use pmap on the PID of my JVM, I can see
lots of
entries for index cfs files.
Does this mean that indexes are mapped into non-heap memory? If so, how
can I monitor the space my process is using if I cache open
IndexSearchers?
The details are:
Sun 64-bit JVM on Linux.
Lucene 3.6 running in 2.3 compatibility mode (as we are in the in the
process of
a migration to 3.6)
Thanks,
- Chris
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