On 10/28/15 5:41 PM, Shawn Heisey wrote:
On 10/28/2015 5:11 PM, Rallavagu wrote:
Seeing very high CPU during this time and very high warmup times. During
this time, there were plenty of these errors logged. So, trying to find
out possible causes for this to occur. Could it be disk I/O issues or
something else as it is related to commit (writing to disk).
Lucene is claiming that you're hitting the Out Of Memory exception. I
pulled down the 4.6.1 source code to verify IndexWriter's behavior. The
only time hitOOM can be set to true is when OutOfMemoryError is being
thrown, so unless you're running Solr built from modified source code,
Lucene's claim *is* what's happening.
This is very likely true as source is not modified.
In OOM situations, there's a good chance that Java is going to be
spending a lot of time doing garbage collection, which can cause CPU
usage to go high and make warm times long.
Again, I think this is the likely case. Even though there is no apparent
OOM, JVM can throw OOM in case of excessive number full GC and unable to
claim certain amount of memory.
The behavior of most Java programs is completely unpredictable when Java
actually runs out of memory. As already mentioned, the parts of Lucene
that update the index are specifically programmed to deal with OOM
without causing index corruption. Writing code that is predictable in
OOM situations is challenging, so only a subset of the code in
Lucene/Solr has been hardened in this way. Most of it is as
unpredictable in OOM as any other Java program.
Thanks Shawn.
Thanks,
Shawn
