Fielddata cache and doc values

Hi,

We are reviewing our ElasticSearch setup & settings, here's a question on
fielddata cache and usage of doc values.

Currently we set fielddata cache to be 30% of the heap size and we've
enabled doc_values for all fields that we want to sort or aggregate (except
2 boolean fields).
As I understand, doc values are a form of on disk cache of field data. So
my questions is, by using doc values, can we reduce the memory fielddata
cache size? Say to 10%, is it a good idea?

Thanks!

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Hi ,

Yes , definitely doc values would be a better idea.
As it is not 100% memory resident , it will give a lot better stability and
memory optimization to the system.
On the flip side, performance might go down to , say 10 to 15%.

Thanks
Vineeth

On Tue, Dec 23, 2014 at 8:47 PM, Han JU ju.han.felix@gmail.com wrote:

Hi,

We are reviewing our ElasticSearch setup & settings, here's a question on
fielddata cache and usage of doc values.

Currently we set fielddata cache to be 30% of the heap size and we've
enabled doc_values for all fields that we want to sort or aggregate (except
2 boolean fields).
As I understand, doc values are a form of on disk cache of field data. So
my questions is, by using doc values, can we reduce the memory fielddata
cache size? Say to 10%, is it a good idea?

Thanks!

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