Am 29.07.2013 14:46, schrieb Michael Ryan: > This is interesting... How are you measuring the heap size?
This is displayed in jvisualvm and also logged with munin via JMX. Bernd > > -Michael > > -----Original Message----- > From: Bernd Fehling [mailto:bernd.fehl...@uni-bielefeld.de] > Sent: Monday, July 29, 2013 5:34 AM > To: solr-user@lucene.apache.org > Subject: swap and GC > > Something interesting I have noticed today, after running my huge single > index (49 mio. records / 137 GB index) for about a week and replicating today > I recognized that the heap usage after replication did not go down as > expected. Expected means if solr is started I have a heap size between 4 to 5 > GB and during the week under heavy load it might go up to 10 GB. But after > replication in offline mode it recovers to between 5 to 6 GB. But today it > was not going under 8 GB, even with forced GC from jvisualvm. > So I first dropped the caches and tried again, no success. > Next I turned off swap which took quite a while and turned it back on. > This forced all content from swap back into memory. After calling Perform GC > from jvisualvm the heap dropped below 5 GB. Bingo! > > This leads me to the conclusion that java GC is not "seeing" or "reaching" > objects which are located in swap. > > Anyone else seen this? > > As I am not short on memory or have any other problems I don't need any > solution, but if there are some users having memory problems with old objects > in swap I would suggest a cronjob after replication with swapoff/swapon and > GC afterwards. > > Bernd >
