Hello,
We recently upgraded to Solr 5.2.1 with jre1.8.0_74 and are seeing long GC
pauses when running jobs that do some hairy faceting. The same jobs worked
fine with our previous 4.6 Solr.
The JVM is configured with 32GB heap with default GC settings, however I've
been tweaking the GC settings to no avail. The latest version had the
following differences from the default config:
XX:ConcGCThreads and XX:ParallelGCThreads are increased from 4 to 7
XX:CMSInitiatingOccupancyFraction increased from 50 to 70
Here is a sample output from the gc_log
2016-04-28T04:36:47.240-0400: 27905.535: Total time for which application
threads were stopped: 0.1667520 seconds, Stopping threads took: 0.0171900
seconds
{Heap before GC invocations=2051 (full 59):
par new generation total 6990528K, used 2626705K [0x00002b16c0000000,
0x00002b18c0000000, 0x00002b18c0000000)
eden space 5592448K, 44% used [0x00002b16c0000000, 0x00002b17571b9948,
0x00002b1815560000)
from space 1398080K, 10% used [0x00002b1815560000, 0x00002b181e8cac28,
0x00002b186aab0000)
to space 1398080K, 0% used [0x00002b186aab0000, 0x00002b186aab0000,
0x00002b18c0000000)
concurrent mark-sweep generation total 25165824K, used 25122205K
[0x00002b18c0000000, 0x00002b1ec0000000, 0x00002b1ec0000000)
Metaspace used 41840K, capacity 42284K, committed 42680K, reserved
43008K
2016-04-28T04:36:49.828-0400: 27908.123: [GC (Allocation Failure)
2016-04-28T04:36:49.828-0400: 27908.124: [CMS2016-04-28T04:36:49.912-0400:
27908.207: [CMS-concurr
ent-abortable-preclean: 5.615/5.862 secs] [Times: user=17.70 sys=2.77,
real=5.86 secs]
(concurrent mode failure): 25122205K->15103706K(25165824K), 8.5567560
secs] 27748910K->15103706K(32156352K), [Metaspace: 41840K->41840K(43008K)],
8.5657830 secs] [
Times: user=8.56 sys=0.01, real=8.57 secs]
Heap after GC invocations=2052 (full 60):
par new generation total 6990528K, used 0K [0x00002b16c0000000,
0x00002b18c0000000, 0x00002b18c0000000)
eden space 5592448K, 0% used [0x00002b16c0000000, 0x00002b16c0000000,
0x00002b1815560000)
from space 1398080K, 0% used [0x00002b1815560000, 0x00002b1815560000,
0x00002b186aab0000)
to space 1398080K, 0% used [0x00002b186aab0000, 0x00002b186aab0000,
0x00002b18c0000000)
concurrent mark-sweep generation total 25165824K, used 15103706K
[0x00002b18c0000000, 0x00002b1ec0000000, 0x00002b1ec0000000)
Metaspace used 41840K, capacity 42284K, committed 42680K, reserved
43008K
}
2016-04-28T04:36:58.395-0400: 27916.690: Total time for which application
threads were stopped: 8.5676090 seconds, Stopping threads took: 0.0003930
seconds
I read the instructions here, https://wiki.apache.org/solr/ShawnHeisey, but
they seem to be specific to Java 7. Are there any updated recommendations
for Java 8?
