Adrien:

Yeah, this is getting warmer. Some of the
CompressingStoredFieldsReader objects are 240M. The documents aren't
nearly that large I don't think (but I'll verify).

But still, over 700 of these objects live at once? I _think_ I'm
seeing the number go up significantly when the number of indexing
threads increases, but that's a bit of indirect evidence. My other
question would be whether you'd expect the number of these objects to
go up as the number of segments goes up, i.e. I assume they're
per-segment....

So the pattern here is atomic updates on documents where some of the
fields get quite large. So the underlying reader has to decompress
these a lot. Do you have any suggestions how to mitigate this? Other
than "don't do that<G>"....

Thanks,
Erick

On Thu, May 9, 2013 at 6:45 AM, Adrien Grand <[email protected]> wrote:
> Hi Erick,
>
> The stored fields reader reuses the buffer used for decompression across
> calls in the same thread, so I'm thinking that this kind of behaviour could
> happen if some documents are very large. Is it the case?
>
> Adrien
>
> Le 8 mai 2013 17:22, "Erick Erickson" <[email protected]> a écrit :
>>
>> I'm seeing a case where (reported to me, not on my personal machine)
>> where Solr's heap is being exhausted apparently by compressed field
>> reader. Here's a sample line from a summary of a heap dump:
>>
>> CompressingStoredFieldReader 735 instances
>>
>> where the CompressingStoredFieldReader instances are taking up 7.5G of
>> heap space (out of 8 allocated). The GC cycles are a pattern I've seen
>> before
>> gc for a long time, recover a few meg
>> run for a _very_ short time
>> gc again, recover a few meg
>>
>> This app happens to be doing a lot of atomic updates, running with CMS
>> collector, java 1.7. There is very little querying going on, and it is
>> happening on several different machines. Solr 4.2.
>>
>> Now, there is a bit of custom update code involved, we're testing whether
>> 1> if not compressing the stored fields changes things
>> 2> if disabling the custom code changes things
>> 3> if Solr 4.3 changes things.
>> 4> whether memory usage grows over time linearly or spikes (pretty
>> sure the former).
>>
>> This is an index-heavy/query-light application, and we're hosing a
>> _bunch_ of documents at the indexing process. But still, assuming that
>> the memory reporting above is accurate, each
>> CompressingStoredFieldReader is apparently taking up 10M each and
>> there are over 700 of them. The documents are being batched (don't
>> quite know how many per batch, will find out).
>>
>> Mainly, I'm asking if this rings any bells. I don't see anything on a
>> quick look at the JIRAs.
>>
>> Thanks,
>> Erick
>>
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