# Need help with performance insights

**URL:** <https://discuss.elastic.co/t/need-help-with-performance-insights/7596>\
**Category:** Elasticsearch\
**Created:** [May 8, 2012, 10:04am UTC](https://discuss.elastic.co/t/need-help-with-performance-insights/7596 "2012-05-08T10:04:04Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Crwe](https://avatars.discourse-cdn.com/v4/letter/c/898d66/32.png) [@Crwe](https://discuss.elastic.co/u/Crwe)\
**Post date:** [May 8, 2012, 10:04am UTC](https://discuss.elastic.co/t/need-help-with-performance-insights/7596/1 "2012-05-08T10:04:04Z")

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Hi all,

are there online resources that summarize how is the performance of  
ElasticSearch/Lucene affected by various factors, like the number of  
documents indexed, number of replicas used, rate of indexing new  
documents, number of facets requested...? Some trench stories, hints,  
insights, big-O overviews.

In particular, I am considering ES for an app and before committing,  
I'd like to know:

The delay between "bulk indexing docs"-\>"these docs available for  
search" is reasonably fast, but I only have a few testing docs in my  
index. How will this delay be affected as the index grows bigger?  
Will this lag increase as I add node replicas?  
As I increase the number of shards?  
What are the ramifications of lowering the "refresh" parameter (I  
understand the default is 1 second)?  
Does it make sense to turn off "refresh", and call refresh manually  
after each bulk-index batch instead?

Cheers!

---

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**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, 3:29am UTC](https://discuss.elastic.co/t/need-help-with-performance-insights/7596/2 "2017-07-06T03:29:50Z")

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