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Posted to user@cassandra.apache.org by Daning <da...@netseer.com> on 2011/09/22 18:51:45 UTC
Lots of GC in log
We are testing Cassandra with pretty big load, I saw frequent GCs in the
log, Do you have suggestion about how to reduce them?
NFO [ScheduledTasks:1] 2011-09-22 09:38:41,080 GCInspector.java (line
122) GC for ParNew: 297 ms for 1 collections, 2503106624 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:39:20,873 GCInspector.java (line
122) GC for ParNew: 376 ms for 1 collections, 2533372976 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:39:22,203 GCInspector.java (line
122) GC for ParNew: 352 ms for 1 collections, 2543060640 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:39:28,286 GCInspector.java (line
122) GC for ParNew: 204 ms for 1 collections, 2643405616 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:39:57,827 GCInspector.java (line
122) GC for ParNew: 231 ms for 1 collections, 2684999576 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:39:59,892 GCInspector.java (line
122) GC for ParNew: 262 ms for 1 collections, 2592862320 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:40:01,901 GCInspector.java (line
122) GC for ParNew: 269 ms for 1 collections, 2707133848 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:40:46,471 GCInspector.java (line
122) GC for ParNew: 340 ms for 1 collections, 2648946352 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:40:48,522 GCInspector.java (line
122) GC for ParNew: 683 ms for 1 collections, 2744305224 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:40:50,784 GCInspector.java (line
122) GC for ParNew: 370 ms for 1 collections, 2713584488 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:41:36,857 GCInspector.java (line
122) GC for ParNew: 241 ms for 1 collections, 2782038560 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:41:50,126 GCInspector.java (line
122) GC for ParNew: 449 ms for 1 collections, 2928576048 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:42:05,399 GCInspector.java (line
122) GC for ParNew: 219 ms for 1 collections, 2869447448 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:42:30,139 GCInspector.java (line
122) GC for ParNew: 207 ms for 1 collections, 3021355184 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:42:31,326 GCInspector.java (line
122) GC for ParNew: 341 ms for 1 collections, 2920592304 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:42:32,815 GCInspector.java (line
122) GC for ParNew: 534 ms for 1 collections, 3024423936 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:42:34,822 GCInspector.java (line
122) GC for ParNew: 216 ms for 1 collections, 3136655600 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:42:42,028 GCInspector.java (line
122) GC for ParNew: 360 ms for 1 collections, 3053516464 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:42:43,544 GCInspector.java (line
122) GC for ParNew: 769 ms for 1 collections, 3072173664 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:42:44,584 GCInspector.java (line
122) GC for ParNew: 279 ms for 1 collections, 3094692872 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:43:00,788 GCInspector.java (line
122) GC for ParNew: 367 ms for 1 collections, 3192674736 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:43:37,051 GCInspector.java (line
122) GC for ParNew: 350 ms for 1 collections, 3400034520 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:43:38,138 GCInspector.java (line
122) GC for ParNew: 270 ms for 1 collections, 3212172456 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:44:00,679 GCInspector.java (line
122) GC for ParNew: 301 ms for 1 collections, 3239850624 used; max is
8015314944
INFO [ScheduledTasks:1] 2011-09-22 09:44:02,690 GCInspector.java (line
122) GC for ParNew: 534 ms for 1 collections, 3308763856 used; max is
8015314944
Thanks in advance.
Daning
Re: Lots of GC in log
Posted by Daning <da...@netseer.com>.
Thanks Peter. I saw cpu was shooting much higher. I am not sure if
frequent GCs are caused by improperly sized generations. I'd like to get
some tunning tips, or good document about Cassandra tuning.
Daning
On 09/22/2011 12:23 PM, Peter Schuller wrote:
>> We are testing Cassandra with pretty big load, I saw frequent GCs in the
>> log, Do you have suggestion about how to reduce them?
> Do you have any actual problem that you are observing?
>
> Frequent young-generation GC:s (ParNew) are expected. If you want to
> cut down on the length of them you may want to change the JVM settings
> in cassandra-env.sh to use a smaller young-gen, but that will probably
> cause overall GC cost to go up as more data is promoted into old gen.
>
Re: Lots of GC in log
Posted by Peter Schuller <pe...@infidyne.com>.
> We are testing Cassandra with pretty big load, I saw frequent GCs in the
> log, Do you have suggestion about how to reduce them?
Do you have any actual problem that you are observing?
Frequent young-generation GC:s (ParNew) are expected. If you want to
cut down on the length of them you may want to change the JVM settings
in cassandra-env.sh to use a smaller young-gen, but that will probably
cause overall GC cost to go up as more data is promoted into old gen.
--
/ Peter Schuller (@scode on twitter)