# Documentation for node level caching and a few caching related questions **URL:** \ **Category:** Elasticsearch\ **Created:** [July 28, 2010, 5:00am UTC](https://discuss.elastic.co/t/documentation-for-node-level-caching-and-a-few-caching-related-questions/3162 "2010-07-28T05:00:51Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![ppearcy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/ppearcy/32/980_2.png) [@ppearcy](https://discuss.elastic.co/u/ppearcy)\ **Post date:** [July 28, 2010, 5:00am UTC](https://discuss.elastic.co/t/documentation-for-node-level-caching-and-a-few-caching-related-questions/3162/1 "2010-07-28T05:00:51Z")
Hi, Came across this feature: > But was not able to find it reflected in the docs. I figured it would be in the Node settings. Also, does this cache hold data for filter queries or other items, as well? While on the topic of caching, I was curious, at what level of granularity are filter queries cached? For example, in the sample query here: [http://www.elasticsearch.com/docs/elasticsearch/rest\_api/query\_dsl/and\_filter/](http://www.elasticsearch.com/docs/elasticsearch/rest_api/query_dsl/and_filter/) Are there two cache objects created for each filter (separate date and name caches) or one cache that holds the results of everything specified in filters? How does this work in the case of nested filters? For the example below, I'd guess one cached item for each filters grouping, so two cached items one for the main filters and the other for the sub- filters. { 'query' : { 'constant\_score' : { 'filter' : { 'and' : { 'filters' : [ { 'term' : {'data' : 600} }, { 'term' : {'symbol' : 'msft'} }, { 'or' : { 'filters' : [ {'term' : { 'Language' : 'en' } }, {'term' : { 'Language' : 'fr' } } ]}} ] } } } } } Thanks! Paul ---
**Author:** ![kimchy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kimchy/32/44952_2.png) [@kimchy](https://discuss.elastic.co/u/kimchy)\ **Post date:** [July 28, 2010, 5:57am UTC](https://discuss.elastic.co/t/documentation-for-node-level-caching-and-a-few-caching-related-questions/3162/2 "2010-07-28T05:57:32Z")
On Wed, Jul 28, 2010 at 8:00 AM, Paul [ppearcy@gmail.com](mailto:ppearcy@gmail.com) wrote: > Hi, > Came across this feature: > [Memory Store / FS Memory: Create a node level memory store cache and allocator · Issue #235 · elastic/elasticsearch · GitHub](http://github.com/elasticsearch/elasticsearch/issues/issue/235) This only relates to a case where you store the index in memory. Actually, I have not documented that change yet... . It basically pre allocated memory for the index to use. Now, this pre-allocated memory is shared between shards. > But was not able to find it reflected in the docs. I figured it would > be in the Node settings. > > Also, does this cache hold data for filter queries or other items, as > well? There are different caches for different aspects in elasticsearch. The above cache only relates to storing the index in memory. > While on the topic of caching, I was curious, at what level of > granularity are filter queries cached? Thats a bit complicated when it comes to Lucene. In general, you should really care about it. If you are familiar with Lucene, then filters are cached on an IndexReader level. > For example, in the sample query here: > > [http://www.elasticsearch.com/docs/elasticsearch/rest\_api/query\_dsl/and\_filter/](http://www.elasticsearch.com/docs/elasticsearch/rest_api/query_dsl/and_filter/) > > Are there two cache objects created for each filter (separate date and > name caches) or one cache that holds the results of everything > specified in filters? It depends on the filter / query (that accepts a filter). In case of AndFilter, only the inner filters are cached. The result is not cached as it make little sense with the And filter implementation to cache them. > How does this work in the case of nested filters? For the example > below, I'd guess one cached item for each filters grouping, so two > cached items one for the main filters and the other for the sub- > filters. > > { > 'query' : { > 'constant\_score' : { > 'filter' : { > 'and' : { > 'filters' : > [ > { > 'term' : {'data' : 600} }, > { > 'term' : {'symbol' : 'msft'} }, > { > 'or' : { > > 'filters' : [ > > ``` > {'term' : { 'Language' : 'en' } }, > > {'term' : { 'Language' : 'fr' } } > > ]}} > ] > } > } > } > } > } > > ``` > > Thanks! > Paul ---
**Author:** ![ppearcy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/ppearcy/32/980_2.png) [@ppearcy](https://discuss.elastic.co/u/ppearcy)\ **Post date:** [July 30, 2010, 12:39am UTC](https://discuss.elastic.co/t/documentation-for-node-level-caching-and-a-few-caching-related-questions/3162/3 "2010-07-30T00:39:31Z")
Hi Shay, Many thanks for the details. If using FS based index storage, are there any caching settings available? Best Regards, Paul On Jul 27, 11:57 pm, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > On Wed, Jul 28, 2010 at 8:00 AM, Paul [ppea...@gmail.com](mailto:ppea...@gmail.com) wrote: > > > Hi, > > Came across this feature: > > [Memory Store / FS Memory: Create a node level memory store cache and allocator · Issue #235 · elastic/elasticsearch · GitHub](http://github.com/elasticsearch/elasticsearch/issues/issue/235) > > This only relates to a case where you store the index in memory. Actually, I > have not documented that change yet... . It basically pre allocated memory > for the index to use. Now, this pre-allocated memory is shared between > shards. > > > But was not able to find it reflected in the docs. I figured it would > > be in the Node settings. > > > Also, does this cache hold data for filter queries or other items, as > > well? > > There are different caches for different aspects in elasticsearch. The above > cache only relates to storing the index in memory. > > > While on the topic of caching, I was curious, at what level of > > granularity are filter queries cached? > > Thats a bit complicated when it comes to Lucene. In general, you should > really care about it. If you are familiar with Lucene, then filters are > cached on an IndexReader level. > > > For example, in the sample query here: > > > [http://www.elasticsearch.com/docs/elasticsearch/rest\_api/query\_dsl/an](http://www.elasticsearch.com/docs/elasticsearch/rest_api/query_dsl/an)... > > > Are there two cache objects created for each filter (separate date and > > name caches) or one cache that holds the results of everything > > specified in filters? > > It depends on the filter / query (that accepts a filter). In case of > AndFilter, only the inner filters are cached. The result is not cached as it > make little sense with the And filter implementation to cache them. > > > How does this work in the case of nested filters? For the example > > below, I'd guess one cached item for each filters grouping, so two > > cached items one for the main filters and the other for the sub- > > filters. > > > { > > 'query' : { > > 'constant\_score' : { > > 'filter' : { > > 'and' : { > > 'filters' : > > [ > > { > > 'term' : {'data' : 600} }, > > { > > 'term' : {'symbol' : 'msft'} }, > > { > > 'or' : { > > > 'filters' : [ > > > ``` > > {'term' : { 'Language' : 'en' } }, > > > > ``` > > > ``` > > {'term' : { 'Language' : 'fr' } } > > > > ``` > > > ``` > > ]}} > > ] > > } > > } > > } > > } > > } > > > > ``` > > > Thanks! > > Paul ---
**Author:** ![kimchy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kimchy/32/44952_2.png) [@kimchy](https://discuss.elastic.co/u/kimchy)\ **Post date:** [July 30, 2010, 11:24am UTC](https://discuss.elastic.co/t/documentation-for-node-level-caching-and-a-few-caching-related-questions/3162/4 "2010-07-30T11:24:17Z")
In elasticsearch, there are two more cached, the first is the filter cache, and the second is the what I call field data cache (field data is used when sorting, faceting, or using scripts). It uses JVM capabilities to cache, so its not like an LRU where you would configure the number of cache entries, eviction strategy and so on. The only option is to disable it, or choose between weak and soft cache. -shay.banon On Fri, Jul 30, 2010 at 3:39 AM, Paul [ppearcy@gmail.com](mailto:ppearcy@gmail.com) wrote: > Hi Shay, > Many thanks for the details. > > If using FS based index storage, are there any caching settings > available? > > Best Regards, > Paul > > On Jul 27, 11:57 pm, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > > On Wed, Jul 28, 2010 at 8:00 AM, Paul [ppea...@gmail.com](mailto:ppea...@gmail.com) wrote: > > > > > Hi, > > > Came across this feature: > > > [Memory Store / FS Memory: Create a node level memory store cache and allocator · Issue #235 · elastic/elasticsearch · GitHub](http://github.com/elasticsearch/elasticsearch/issues/issue/235) > > > > This only relates to a case where you store the index in memory. > > Actually, I > > have not documented that change yet... . It basically pre allocated > > memory > > for the index to use. Now, this pre-allocated memory is shared between > > shards. > > > > > But was not able to find it reflected in the docs. I figured it would > > > be in the Node settings. > > > > > Also, does this cache hold data for filter queries or other items, as > > > well? > > > > There are different caches for different aspects in elasticsearch. The > > above > > cache only relates to storing the index in memory. > > > > > While on the topic of caching, I was curious, at what level of > > > granularity are filter queries cached? > > > > Thats a bit complicated when it comes to Lucene. In general, you should > > really care about it. If you are familiar with Lucene, then filters are > > cached on an IndexReader level. > > > > > For example, in the sample query here: > > > > > [http://www.elasticsearch.com/docs/elasticsearch/rest\_api/query\_dsl/an](http://www.elasticsearch.com/docs/elasticsearch/rest_api/query_dsl/an). > > > .. > > > > > Are there two cache objects created for each filter (separate date and > > > name caches) or one cache that holds the results of everything > > > specified in filters? > > > > It depends on the filter / query (that accepts a filter). In case of > > AndFilter, only the inner filters are cached. The result is not cached as > > it > > make little sense with the And filter implementation to cache them. > > > > > How does this work in the case of nested filters? For the example > > > below, I'd guess one cached item for each filters grouping, so two > > > cached items one for the main filters and the other for the sub- > > > filters. > > > > > { > > > 'query' : { > > > 'constant\_score' : { > > > 'filter' : { > > > 'and' : { > > 'filters' : > > > > [ > > { > > > > 'term' : {'data' : 600} }, > > { > > > > 'term' : {'symbol' : 'msft'} }, > > { > > > > 'or' : { > > > > > 'filters' : [ > > > > > ``` > > > {'term' : { 'Language' : 'en' } }, > > > > > > ``` > > > > > ``` > > > {'term' : { 'Language' : 'fr' } } > > > > > > ``` > > > > > ``` > > > ]}} > > > > > > ``` > > ] > > > > ``` > > > } > > > } > > > } > > > } > > > } > > > > > > ``` > > > > > Thanks! > > > Paul ---
**Author:** ![otisg](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/otisg/32/492_2.png) [@otisg](https://discuss.elastic.co/u/otisg)\ **Post date:** [July 30, 2010, 3:11pm UTC](https://discuss.elastic.co/t/documentation-for-node-level-caching-and-a-few-caching-related-questions/3162/5 "2010-07-30T15:11:18Z")
Hi Shay, On Jul 30, 7:24 am, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > In elasticsearch, there are two more cached, the first is the filter cache, > and the second is the what I call field data cache (field data is used when > sorting, faceting, or using scripts). It uses JVM capabilities to cache, so > its not like an LRU where you would configure the number of cache entries, > eviction strategy and so on. The only option is to disable it, or choose > between weak and soft cache. I imagine the filter cache is actually ES-specific code. Is the field data cache also ES-specific, or are you referring to Lucene's FieldCache? ## Thanks, Otis Sematext :: [http://sematext.com/](http://sematext.com/) :: Solr - Lucene - Nutch Lucene ecosystem search :: [http://search-lucene.com/](http://search-lucene.com/) > -shay.banon > > On Fri, Jul 30, 2010 at 3:39 AM, Paul [ppea...@gmail.com](mailto:ppea...@gmail.com) wrote: > > > Hi Shay, > > Many thanks for the details. > > > If using FS based index storage, are there any caching settings > > available? > > > Best Regards, > > Paul > > > On Jul 27, 11:57 pm, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > > > > On Wed, Jul 28, 2010 at 8:00 AM, Paul [ppea...@gmail.com](mailto:ppea...@gmail.com) wrote: > > > > > > > Hi, > > > > Came across this feature: > > > > [Memory Store / FS Memory: Create a node level memory store cache and allocator · Issue #235 · elastic/elasticsearch · GitHub](http://github.com/elasticsearch/elasticsearch/issues/issue/235) > > > > This only relates to a case where you store the index in memory. > > > Actually, I > > > have not documented that change yet... . It basically pre allocated > > > memory > > > for the index to use. Now, this pre-allocated memory is shared between > > > shards. > > > > > But was not able to find it reflected in the docs. I figured it would > > > > be in the Node settings. > > > > > Also, does this cache hold data for filter queries or other items, as > > > > well? > > > > There are different caches for different aspects in elasticsearch. The > > > above > > > cache only relates to storing the index in memory. > > > > > While on the topic of caching, I was curious, at what level of > > > > granularity are filter queries cached? > > > > Thats a bit complicated when it comes to Lucene. In general, you should > > > really care about it. If you are familiar with Lucene, then filters are > > > cached on an IndexReader level. > > > > > For example, in the sample query here: > > > > > [http://www.elasticsearch.com/docs/elasticsearch/rest\_api/query\_dsl/an](http://www.elasticsearch.com/docs/elasticsearch/rest_api/query_dsl/an). > > > > .. > > > > > Are there two cache objects created for each filter (separate date and > > > > name caches) or one cache that holds the results of everything > > > > specified in filters? > > > > It depends on the filter / query (that accepts a filter). In case of > > > AndFilter, only the inner filters are cached. The result is not cached as > > > it > > > make little sense with the And filter implementation to cache them. > > > > > How does this work in the case of nested filters? For the example > > > > below, I'd guess one cached item for each filters grouping, so two > > > > cached items one for the main filters and the other for the sub- > > > > filters. > > > > > { > > > > 'query' : { > > > > 'constant\_score' : { > > > > 'filter' : { > > > > 'and' : { > > > 'filters' : > > > > > > [ > > > { > > > > > > 'term' : {'data' : 600} }, > > > { > > > > > > 'term' : {'symbol' : 'msft'} }, > > > { > > > > > > 'or' : { > > > > > 'filters' : [ > > > > > ``` > > > > {'term' : { 'Language' : 'en' } }, > > > > > > > > ``` > > > > > ``` > > > > {'term' : { 'Language' : 'fr' } } > > > > > > > > ``` > > > > > ``` > > > > ]}} > > > > > > > > ``` > > > ] > > > > > > ``` > > > > } > > > > } > > > > } > > > > } > > > > } > > > > > > > > ``` > > > > > Thanks! > > > > Paul ---
**Author:** ![kimchy](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/kimchy/32/44952_2.png) [@kimchy](https://discuss.elastic.co/u/kimchy)\ **Post date:** [July 30, 2010, 3:52pm UTC](https://discuss.elastic.co/t/documentation-for-node-level-caching-and-a-few-caching-related-questions/3162/6 "2010-07-30T15:52:37Z")
The field data cache is elasticsearch specific, it replaces Lucene FieldCache, but serves similar purpose (with extended functionality) with the ability to use it for other cases like facets and scripts. I tried to get some of the mentioned enhancements to Lucene but got pushed back (like using concurrent soft map). -shay.banon On Fri, Jul 30, 2010 at 6:11 PM, Otis [otis.gospodnetic@gmail.com](mailto:otis.gospodnetic@gmail.com) wrote: > Hi Shay, > > On Jul 30, 7:24 am, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > > In elasticsearch, there are two more cached, the first is the filter > > cache, > > and the second is the what I call field data cache (field data is used > > when > > sorting, faceting, or using scripts). It uses JVM capabilities to cache, > > so > > its not like an LRU where you would configure the number of cache > > entries, > > eviction strategy and so on. The only option is to disable it, or choose > > between weak and soft cache. > > I imagine the filter cache is actually ES-specific code. Is the field > data cache also ES-specific, or are you referring to Lucene's > FieldCache? > > ## Thanks, Otis > > Sematext :: [http://sematext.com/](http://sematext.com/) :: Solr - Lucene - Nutch > Lucene ecosystem search :: [http://search-lucene.com/](http://search-lucene.com/) > > > -shay.banon > > > > On Fri, Jul 30, 2010 at 3:39 AM, Paul [ppea...@gmail.com](mailto:ppea...@gmail.com) wrote: > > > > > Hi Shay, > > > Many thanks for the details. > > > > > If using FS based index storage, are there any caching settings > > > available? > > > > > Best Regards, > > > Paul > > > > > On Jul 27, 11:57 pm, Shay Banon [shay.ba...@elasticsearch.com](mailto:shay.ba...@elasticsearch.com) wrote: > > > > > > > On Wed, Jul 28, 2010 at 8:00 AM, Paul [ppea...@gmail.com](mailto:ppea...@gmail.com) wrote: > > > > > > > > > Hi, > > > > > Came across this feature: > > > > > [Memory Store / FS Memory: Create a node level memory store cache and allocator · Issue #235 · elastic/elasticsearch · GitHub](http://github.com/elasticsearch/elasticsearch/issues/issue/235) > > > > > > This only relates to a case where you store the index in memory. > > > > Actually, I > > > > have not documented that change yet... . It basically pre allocated > > > > memory > > > > for the index to use. Now, this pre-allocated memory is shared > > > > between > > > > shards. > > > > > > > But was not able to find it reflected in the docs. I figured it > > > > > would > > > > > be in the Node settings. > > > > > > > Also, does this cache hold data for filter queries or other items, > > > > > as > > > > > well? > > > > > > There are different caches for different aspects in elasticsearch. > > > > The > > > > above > > > > cache only relates to storing the index in memory. > > > > > > > While on the topic of caching, I was curious, at what level of > > > > > granularity are filter queries cached? > > > > > > Thats a bit complicated when it comes to Lucene. In general, you > > > > should > > > > really care about it. If you are familiar with Lucene, then filters > > > > are > > > > cached on an IndexReader level. > > > > > > > For example, in the sample query here: > > > > > > > > > [http://www.elasticsearch.com/docs/elasticsearch/rest\_api/query\_dsl/an](http://www.elasticsearch.com/docs/elasticsearch/rest_api/query_dsl/an). > > > > .. > > > > > > > Are there two cache objects created for each filter (separate date > > > > > and > > > > > name caches) or one cache that holds the results of everything > > > > > specified in filters? > > > > > > It depends on the filter / query (that accepts a filter). In case of > > > > AndFilter, only the inner filters are cached. The result is not > > > > cached as > > > > it > > > > make little sense with the And filter implementation to cache them. > > > > > > > How does this work in the case of nested filters? For the example > > > > > below, I'd guess one cached item for each filters grouping, so two > > > > > cached items one for the main filters and the other for the sub- > > > > > filters. > > > > > > > { > > > > > 'query' : { > > > > > 'constant\_score' : { > > > > > 'filter' : { > > > > > 'and' : { > > > > > 'filters' : > > > > > > > > [ > > > > > { > > > > > > > > 'term' : {'data' : 600} }, > > > > > { > > > > > > > > 'term' : {'symbol' : 'msft'} }, > > > > > { > > > > > > > > 'or' : { > > > > > > > 'filters' : [ > > > > > > > ``` > > > > > {'term' : { 'Language' : 'en' } }, > > > > > > > > > > ``` > > > > > > > ``` > > > > > {'term' : { 'Language' : 'fr' } } > > > > > > > > > > ``` > > > > > > > ``` > > > > > ]}} > > > > > > > > > > ``` > > > > > ] > > > > > > > > ``` > > > > > } > > > > > } > > > > > } > > > > > } > > > > > } > > > > > > > > > > ``` > > > > > > > Thanks! > > > > > Paul ---
**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\ **Post date:** [July 6, 2017, 4:21am UTC](https://discuss.elastic.co/t/documentation-for-node-level-caching-and-a-few-caching-related-questions/3162/7 "2017-07-06T04:21:22Z")