# How to keep on x no of recent documents based on field
**URL:** https://discuss.elastic.co/t/how-to-keep-on-x-no-of-recent-documents-based-on-field/196822
**Category:** Elasticsearch
**Created:** [August 26, 2019, 6:29pm UTC](https://discuss.elastic.co/t/how-to-keep-on-x-no-of-recent-documents-based-on-field/196822 "2019-08-26T18:29:00Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@saurabh\_baid](https://discuss.elastic.co/u/saurabh_baid)
#### Post date: [August 26, 2019, 6:29pm UTC](https://discuss.elastic.co/t/how-to-keep-on-x-no-of-recent-documents-based-on-field/196822/1 "2019-08-26T18:29:01Z")
We are trying to evaluate elasticsearch for keeping up our events and very impressed so far.
Though there are two issues we need help with
- We need to only keep X no of events per MAC address and old events should be purged. Since MAC could be in order of thousands obviously having separate indexes per mac is out of question.
I am assuming that this should be possible using aggregation and pipelines but now sure how
- Is there a way we can get metric of No of query served during a time period, we need this info for our own benchmarking purposes.
Thanks in advance.
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### Author:  [@saurabh\_baid](https://discuss.elastic.co/u/saurabh_baid)
#### Post date: [August 26, 2019, 8:15pm UTC](https://discuss.elastic.co/t/how-to-keep-on-x-no-of-recent-documents-based-on-field/196822/2 "2019-08-26T20:15:29Z")
So currently I am using following approach
- Iterate through all the macs
- For each mac
- Once I have that
Now this is certainly not the efficient way, Is there a way to combine all three steps into one aggregation/pipeline.
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [September 23, 2019, 8:15pm UTC](https://discuss.elastic.co/t/how-to-keep-on-x-no-of-recent-documents-based-on-field/196822/3 "2019-09-23T20:15:32Z")
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