There are a couple of steps you can take if compaction is causing GC. - if you have a lot of wide rows consider reducing the in_memory_compaction_limit_in_mb yaml setting. This will slow down compaction but will reduce the memory usage.
- reduce concurrent_compactors Both of these may slow down compaction. Once you have GC under control you may want to play with memory settings. Hope that helps. ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 14/08/2012, at 4:45 PM, Tamar Fraenkel <ta...@tok-media.com> wrote: > Hi! > I have 3 nodes ring running on Amazon EC2. > About once a week I see in the logs compaction messages and around the same > time info messages about GC (see below) that I think means it is taking too > long and happening too often. > > Does it mean I have to reduce my cache size? > Thanks, > Tamar > > INFO [ScheduledTasks:1] 2012-08-13 12:50:57,593 GCInspector.java (line 122) > GC for ParNew: 242 ms for 1 collections, 1541590352 used; max is 1937768448 > INFO [ScheduledTasks:1] 2012-08-13 12:51:27,740 GCInspector.java (line 122) > GC for ParNew: 291 ms for 1 collections, 1458227032 used; max is 1937768448 > INFO [ScheduledTasks:1] 2012-08-13 12:51:29,741 GCInspector.java (line 122) > GC for ParNew: 261 ms for 1 collections, 1228861368 used; max is 1937768448 > INFO [ScheduledTasks:1] 2012-08-13 12:51:30,833 GCInspector.java (line 122) > GC for ParNew: 319 ms for 1 collections, 1120131360 used; max is 1937768448 > INFO [ScheduledTasks:1] 2012-08-13 12:51:32,863 GCInspector.java (line 122) > GC for ParNew: 241 ms for 1 collections, 983144216 used; max is 1937768448 > INFO [ScheduledTasks:1] 2012-08-13 12:51:33,864 GCInspector.java (line 122) > GC for ParNew: 215 ms for 1 collections, 967702720 used; max is 1937768448 > INFO [ScheduledTasks:1] 2012-08-13 12:51:34,964 GCInspector.java (line 122) > GC for ParNew: 248 ms for 1 collections, 973803344 used; max is 1937768448 > INFO [ScheduledTasks:1] 2012-08-13 12:51:41,211 GCInspector.java (line 122) > GC for ParNew: 265 ms for 1 collections, 1071933560 used; max is 1937768448 > INFO [ScheduledTasks:1] 2012-08-13 12:51:43,212 GCInspector.java (line 122) > GC for ParNew: 326 ms for 1 collections, 1217367792 used; max is 1937768448 > INFO [ScheduledTasks:1] 2012-08-13 12:51:44,212 GCInspector.java (line 122) > GC for ParNew: 245 ms for 1 collections, 1203481536 used; max is 1937768448 > INFO [ScheduledTasks:1] 2012-08-13 12:51:45,213 GCInspector.java (line 122) > GC for ParNew: 209 ms for 1 collections, 1208819416 used; max is 1937768448 > INFO [ScheduledTasks:1] 2012-08-13 12:51:46,237 GCInspector.java (line 122) > GC for ParNew: 248 ms for 1 collections, 1338361648 used; max is 1937768448 > > > Tamar Fraenkel > Senior Software Engineer, TOK Media > > <tokLogo.png> > > ta...@tok-media.com > Tel: +972 2 6409736 > Mob: +972 54 8356490 > Fax: +972 2 5612956 > > >
