This really depends on the GC parameters specified to the JVM. I have not found (so far) that Derby has a memory leak with my setup and mix of operations. The JVM you are using will have many different options on the GC parameters, algorithms, etc.. Do a search on JVM tuning and you will find many pages describing these. I currently am in the process of trying the various combinations for my setup as my situation cannot tolerate long (more than 5 second) GC pauses, so I need to tune for low pause times at the expense of throughput.
On Jun 10, 2014, at 4:41 AM, Chris Olver <chris.ol...@3plearning.com> wrote: > Hi Brett, > > Many thanks for your help, VisualVM showed up the issue and you were indeed > correct.. It was ignoring the commands of increasing the heap. I have now got > a fresh version of the startNetworkService and made the necessary changes. It > now runs well.. One question from this experience, using VisualVM I can see > over multiple hours the HeapSpace continues to grow and doesn't garbage > collect. Is there a setting or timer which can garbage collect the heap more > frequently? > > Kind regards, > > Chris Olver > > > > > -----Original Message----- > From: Bergquist, Brett [mailto:bbergqu...@canoga.com] > Sent: 06 June 2014 23:21 > To: Derby Discussion > Subject: RE: Apache Derby - Locks up. > > Maybe connect up with jvisualvm to the process and see what it is reporting. > Jvisualvm will show the environment of the process. Since you are > specifying both a -Xmx and -Xms, the heap should be initially allocated to > your 6G and never grow or shrink. Jvisualvm will show if that is it is doing > so. > > It seems strange that it is requiring so much memory. Yes your row count is > high but I have tables in my database that are regularly 10M records that are > queried every 5 minutes with no issue and I can do so with a much smaller > memory setting (4G is what I am using in testing). > > Derby can work in an environment like this as one system that we have has > tables that are inserted into about 10M records/day with no issues. > > -----Original Message----- > From: Chris Olver [mailto:chris.ol...@3plearning.com] > Sent: Thursday, June 05, 2014 11:42 PM > To: Derby Discussion > Subject: RE: Apache Derby - Locks up. > > Just before it locked up, I managed to get this: > > --- Derby Network Server Runtime Information --- > ---------- Session Information --------------- Session # :4 Database :etl > User :a # Statements:1 Prepared Statement Information: > Stmt ID SQLText > ------------- ----------- > SYSLH0001 SELECT * FROM APP.PROFILES > > Session # :19 > > ------------------------------------------------------------- > # Connection Threads : 2 > # Active Sessions : 2 > # Waiting Sessions : 0 > > Total Memory : 3042443264 Free Memory : 153934376 > > So I'm not sure what heap size it is reaching. > > Regards, > > -Chris > > > -----Original Message----- > From: Bryan Pendleton [mailto:bpendleton.de...@gmail.com] > Sent: 06 June 2014 12:32 > To: Derby Discussion > Subject: Re: Apache Derby - Locks up. > > It's interesting that you are trying to set it to use 6 G, and yet in your > other message there was the line: > >> Total Memory : 1756889088 Free Memory : 306272128 > > which seems to indicate that it's only using 1.7 GB. > > Like maybe you're running a 32 bit JVM, not a 64 bit JVM, somehow? > > bryan
