# Memory usage in index
**URL:** https://discuss.elastic.co/t/memory-usage-in-index/228549
**Category:** Elasticsearch
**Created:** [April 17, 2020, 4:33pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549 "2020-04-17T16:33:32Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Rajeev\_Bhat](https://discuss.elastic.co/u/Rajeev_Bhat)
#### Post date: [April 17, 2020, 4:33pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/1 "2020-04-17T16:33:33Z")
Hello,
I am new to ELasticSearch..I created an index and populated with around 500thousand documents.
How can I check what % of my documents are in RAM and how much is stored in disk?
Thanks
Rajeev
---
### Author:  [@dadoonet](https://discuss.elastic.co/u/dadoonet)
#### Post date: [April 17, 2020, 5:12pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/2 "2020-04-17T17:12:15Z")
Welcome!
Everything is stored on disk.
---
### Author:  [@Rajeev\_Bhat](https://discuss.elastic.co/u/Rajeev_Bhat)
#### Post date: [April 18, 2020, 3:10am UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/3 "2020-04-18T03:10:15Z")
Thank you 😊
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### Author:  [@Rajeev\_Bhat](https://discuss.elastic.co/u/Rajeev_Bhat)
#### Post date: [April 18, 2020, 1:44pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/4 "2020-04-18T13:44:12Z")
Hey,
Is there any way I can store in RAM to speed up response time?
---
### Author:  [@Christian\_Dahlqvist](https://discuss.elastic.co/u/Christian_Dahlqvist)
#### Post date: [April 18, 2020, 2:39pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/5 "2020-04-18T14:39:21Z")
Files on disk are cached in the operating system page cache, so having lots of RAM available will speed up queries this way. Elastic also uses off-heap memory for some data in additional to the allocated heap.
---
### Author:  [@dadoonet](https://discuss.elastic.co/u/dadoonet)
#### Post date: [April 18, 2020, 3:19pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/6 "2020-04-18T15:19:54Z")
What is the current response time you have?
---
### Author:  [@Rajeev\_Bhat](https://discuss.elastic.co/u/Rajeev_Bhat)
#### Post date: [April 18, 2020, 4:42pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/7 "2020-04-18T16:42:23Z")
@dadoonet It is around 150 to 200 ms for simple queries. Even if I run same query why the response time varies every time?
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### Author:  [@Rajeev\_Bhat](https://discuss.elastic.co/u/Rajeev_Bhat)
#### Post date: [April 18, 2020, 4:46pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/8 "2020-04-18T16:46:28Z")
Will every document in index is cached?
When queried , will the results fetched from disk(secondary memory) or page cache?
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### Author:  [@dadoonet](https://discuss.elastic.co/u/dadoonet)
#### Post date: [April 19, 2020, 1:07am UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/9 "2020-04-19T01:07:18Z")
Could you share your query and the response?
---
### Author:  [@Rajeev\_Bhat](https://discuss.elastic.co/u/Rajeev_Bhat)
#### Post date: [April 19, 2020, 4:06pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/10 "2020-04-19T16:06:07Z")
**Curl call:**
`curl -X GET "localhost:9200/test/_search?q=JamesTown&pretty"`
**Response:**
```auto
{
"took" : 169,
"timed_out" : false,
"_shards" : {
"total" : 5,
"successful" : 5,
"skipped" : 0,
"failed" : 0
},
"hits" : {
"total" : 2,
"max_score" : 7.391895,
"hits" : [
{
"_index" : "test",
"_type" : "_doc",
"_id" : "airport_5745",
"_score" : 7.391895,
"_source" : {
"airportname" : "Jamestown Regional Airport",
"city" : "Jamestown",
"country" : "United States",
"faa" : "JMS",
"geo" : {
"alt" : 1498.0,
"lat" : 46.9297,
"lon" : -98.6782
},
"icao" : "KJMS",
"id" : 5745,
"type" : "airport",
"tz" : "America/Chicago"
}
},
{
"_index" : "test",
"_type" : "_doc",
"_id" : "airport_7059",
"_score" : 7.391895,
"_source" : {
"airportname" : "Chautauqua County-Jamestown",
"city" : "Jamestown",
"country" : "United States",
"faa" : "JHW",
"geo" : {
"alt" : 525.0,
"lat" : 42.153333,
"lon" : -79.258056
},
"icao" : "KJHW",
"id" : 7059,
"type" : "airport",
"tz" : "America/New_York"
}
}
]
}
}
```
FYI my use case is FullTextSearch. User may search on any field.
---
### Author:  [@dadoonet](https://discuss.elastic.co/u/dadoonet)
#### Post date: [April 19, 2020, 5:54pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/11 "2020-04-19T17:54:05Z")
If you have only 500k documents, I'd use only one shard. That could help.
---
### Author:  [@Rajeev\_Bhat](https://discuss.elastic.co/u/Rajeev_Bhat)
#### Post date: [April 20, 2020, 2:49am UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/12 "2020-04-20T02:49:35Z")
I will try it.
Thanks
---
### Author:  [@Rajeev\_Bhat](https://discuss.elastic.co/u/Rajeev_Bhat)
#### Post date: [April 20, 2020, 3:48am UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/13 "2020-04-20T03:48:55Z")
Can we get to know how much % of docs are in page cache if the RAM is less?
---
### Author:  [@Rajeev\_Bhat](https://discuss.elastic.co/u/Rajeev_Bhat)
#### Post date: [April 21, 2020, 1:38pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/14 "2020-04-21T13:38:48Z")
Hey, I tried with only one shard, It is taking almost same time sometimes more.
---
### Author:  [@dadoonet](https://discuss.elastic.co/u/dadoonet)
#### Post date: [April 21, 2020, 2:02pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/15 "2020-04-21T14:02:33Z")
What kind of hardware do you have?
---
### Author:  [@Rajeev\_Bhat](https://discuss.elastic.co/u/Rajeev_Bhat)
#### Post date: [April 21, 2020, 2:08pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/16 "2020-04-21T14:08:23Z")
Using Virtual Machine with ~32 GB RAM
---
### Author:  [@dadoonet](https://discuss.elastic.co/u/dadoonet)
#### Post date: [April 21, 2020, 2:11pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/17 "2020-04-21T14:11:54Z")
What kind of drives do you have?
---
### Author:  [@Rajeev\_Bhat](https://discuss.elastic.co/u/Rajeev_Bhat)
#### Post date: [April 21, 2020, 2:18pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/18 "2020-04-21T14:18:04Z")
Normal HDD, not SSD
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### Author:  [@dadoonet](https://discuss.elastic.co/u/dadoonet)
#### Post date: [April 21, 2020, 2:19pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/19 "2020-04-21T14:19:31Z")
That might explain then.
Is it still slow after some runs? It should be cached by the OS at some point.
---
### Author:  [@Rajeev\_Bhat](https://discuss.elastic.co/u/Rajeev_Bhat)
#### Post date: [April 21, 2020, 2:26pm UTC](https://discuss.elastic.co/t/memory-usage-in-index/228549/20 "2020-04-21T14:26:36Z")
Yes, After some runs it's better. But for some new queries it is again taking long time.
Thanks for your support.
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