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From Shawn Heisey <>
Subject Re: out of memory during indexing do to large incoming queue
Date Sun, 02 Jun 2013 19:53:20 GMT
On 6/2/2013 12:25 PM, Yoni Amir wrote:
> Hi Shawn and Shreejay, thanks for the response.
> Here is some more information:
> 1) The machine is a virtual machine on ESX server. It has 4 CPUs and 8GB of RAM. I don't
remember what CPU but something modern enough. It is running Java 7 without any special parameters,
and 4GB allocated for Java (-Xmx)
> 2) After successful indexing, I have 2.5 Million documents, 117GB index size. This is
the size after it was optimized.
> 3) I plan to upgrade to 4.3 just didn't have time. 4.0 beta is what was available at
the time that we had a release deadline.
> 4) The setup with master-slave replication, not Solr Cloud. The server that I am discussing
is the indexing server, and in these tests there were actually no slaves involved, and virtually
zero searches performed.
> 5) Attached is my configuration. I tried to disable the warm-up and opening of searchers,
it didn't change anything. The commits are done by Solr, using autocommit. The client sends
the updates without a commit command.
> 6) I want to disable optimization, but when I disabled it, the OOME occurred even faster.
The number of segments reached around a thousand within an hour or so. I don't know if it's
normal or not, but at that point if I restarted Solr it immediately took about 1GB of heap
space just on start-up, instead of the usual 50MB or so.
> If I commit less frequently, don't I increase the risk of losing data, e.g., if the power
goes down, etc.?
> If I disable optimization, is it necessary to avoid such a large number of segments?
Is it possible?

Last part first: Losing data is much less of a risk with Solr 4.x, if
you have enabled the updateLog.

We'll need some more info.  See the end of the message for specifics.

Right off the bat, I can tell you that with an index that's 117GB,
you're going to need a LOT of RAM.

Each of my 4.2.1 servers has 42GB of index and about 37 million
documents between all the index shards.  The web application never uses
facets, which tend to use a lot of memory.  My index is a lot smaller
than yours, and I need a 6GB heap, seeing OOM errors if it's only 4GB.
You probably need at least an 8GB heap, and possibly larger.

Beyond the amount of memory that Solr itself uses, for good performance
you will also need a large amount of memory for OS disk caching.  Unless
the server is using SSD, you need to allocate at least 64GB of real
memory to the virtual machine.  If you've got your index on SSD, 32GB
might be enough.  I've got 64GB total on my servers.

When you say that there are over 1000 segments, are you seeing 1000
files, or are there literally 1000 segments, giving you between 12000
and 15000 files?  Even if your mergeFactor were higher than the default
10, that just shouldn't happen.

Can you share your solrconfig.xml and schema.xml?  Use a paste website
like and share the URLs.


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