# Completion suggester strange behavior after index optimization

**URL:** <https://discuss.elastic.co/t/completion-suggester-strange-behavior-after-index-optimization/54240>\
**Category:** Elasticsearch\
**Created:** [June 29, 2016, 6:22am UTC](https://discuss.elastic.co/t/completion-suggester-strange-behavior-after-index-optimization/54240 "2016-06-29T06:22:40Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![mat2](https://avatars.discourse-cdn.com/v4/letter/m/bcef8e/32.png) [@mat2](https://discuss.elastic.co/u/mat2)\
**Post date:** [June 29, 2016, 6:22am UTC](https://discuss.elastic.co/t/completion-suggester-strange-behavior-after-index-optimization/54240/1 "2016-06-29T06:22:40Z")

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Hi

I have got a dataset (\>60m documents). I'm trying to build an autocomplete functionality using Completion Suggester. Every document has a custom "score" assigned (integer min. 1000, max. about 40 000) that represents it's importance, so I used this score as weight in my completion field.

Right after index is finished building, I am able to search all documents and completion suggester provides relevant names ordered by weight. However, it works only for a few minutes after rebuilding the index. During that time Marvel shows some activity (index size changes, although document count stays the same). I suspect that's when ES is doing some of it's internal optimizations. After all work is finished, completion suggester returns different results.

Example:  
Searching for suggestions for "mic".  
a) Results when index is finished building, but not finished optimizing (index size changes over time):  
text: "Microprocessor", score: 37000  
text: "Micron", score: 32000  
text: "Microchip", score: 31500  
text: "Micro controller", score: 28000

b) Results when index is finished building and optimizing (I wait until all charts on Marvel are flat):  
text: "Micro controller", score: 28000  
text: "Microphone", score: 27000  
text: "Microwave", score: 22000  
text: "Mickey Mouse", score: 21000

So basically some suggestions are missing after optimizations. What's more, for some queries running the same query twice gives different results (sometimes "Microprocessor" is in the results, so I get [Microprocessor, Micro controller, Microphone, Microwave]). When it happens (it happens for some queries, and for others it doesn't), it's weirdly consistent (i.e. every second "mic" query I get "Microprocessor" as the first result).

The described situation happens only for suggestion queries (POST my\_index/\_suggest). All search queries (POST my\_index/\_search) produce good, consistent results whenever I use them.

My configuration consists of 3 servers (nodes). The data is split into 3 shards (0,1,2) with 2 shards per node (1-st node: shard 0 + replica 2; 2-nd node: shard 2 + replica 1; 3-rd node: shard 1 + replica 0). The results are the same regardless of which node I send my request to.

My ES version: 2.2.1  
Lucene version: 5.4.1

Have you ever encountered such behavior?

Regards  
Matthew

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**Author:** ![CCMBChina](https://avatars.discourse-cdn.com/v4/letter/c/858c86/32.png) [@CCMBChina](https://discuss.elastic.co/u/CCMBChina)\
**Post date:** [December 20, 2016, 6:23am UTC](https://discuss.elastic.co/t/completion-suggester-strange-behavior-after-index-optimization/54240/2 "2016-12-20T06:23:45Z")

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> [@mat2](#):
>
> My ES version: 2.2.1Lucene version: 5.4.1

now do you work out it? i also encounter this problems at this version

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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 5, 2017, 10:04pm UTC](https://discuss.elastic.co/t/completion-suggester-strange-behavior-after-index-optimization/54240/3 "2017-07-05T22:04:46Z")

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