Strange behaviour of G1 GC

[Alexander Bulaev]

Full log file is available at https://www.dropbox.com/s/w17iyy2cxsmhgyo/web-gc.log

On 25.07.2014, at 11:30, Alexander Bulaev <alexbool at yandex-team.ru> wrote:

> Hello!
> 
> I am writing to you about strange behaviuor of G1 GC that I have encountered in our production environment.
> Sometimes there are happening Full GCs that are cleaning a lot of garbage:
> 2014-07-24T14:27:57.020+0400: 94749.771: [Full GC (Allocation Failure)  11G->5126M(12G), 13.7944745 secs]
> 
> I suppose that this is garbage in the old generation. I expect it to be cleaned during mixed and concurrent GCs, but, according to the logs, the last concurrent phase happened over half an hour earlier prior to that Full GC:
> 2014-07-24T13:49:43.228+0400: 92455.979: [GC concurrent-mark-start]
> 
> And there is no evidence in logs that this concurrent mark has ever ended. Seems like that concurrent GC just hang somewhere.
> Same thing with mixed GCs:
> 2014-07-24T13:42:47.425+0400: 92040.176: [GC pause (G1 Evacuation Pause) (mixed)
> 
> Please help me understand this problem and find a solution if possible.
> We are using Java 8u5. I can supply these GC logs if needed.
> Thanks.
> 
> Best regards,
> Alexander Bulaev
> Java developer, Yandex LLC

Best regards,
Alexander Bulaev
Java developer, Yandex LLC