# Indices.memory.index\_buffer\_size. documentation is ambiguous

**URL:** <https://discuss.elastic.co/t/indices-memory-index-buffer-size-documentation-is-ambiguous/110215>\
**Category:** Elasticsearch\
**Created:** [December 4, 2017, 9:38pm UTC](https://discuss.elastic.co/t/indices-memory-index-buffer-size-documentation-is-ambiguous/110215 "2017-12-04T21:38:12Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![tumux](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/tumux/32/24932_2.png) [@tumux](https://discuss.elastic.co/u/tumux)\
**Post date:** [December 4, 2017, 9:38pm UTC](https://discuss.elastic.co/t/indices-memory-index-buffer-size-documentation-is-ambiguous/110215/1 "2017-12-04T21:38:12Z")

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Continuing the discussion from [Index\_buffer\_size vs max\_index\_buffer\_size](https://discuss.elastic.co/t/index-buffer-size-vs-max-index-buffer-size/39586/2):

it says:  
"The min and max are taken into account only when index\_buffer\_size is a percentage. In that case the min and max may override index\_buffer\_size depending on how much memory is available.

I'll see if we can get the docs updated to reflect this."

since the documentation is not updated yet - I will leave my assumptions/thoughts here. Maybe someone will respond.

So for me it is very hard to understand what does it mean to have two limiting values for the same amount at the same time:

if by default index\_buffer\_size is 10% of heap size and max\_index\_bufer\_size - is entire heap size.  
then

what does it look like on (for example) a cluster node wtih 32GB heap size:

index\_buffer\_size is 10% (or 3.2 GB in bulk numbers)  
index\_max\_index\_buffer\_size is 32 GB ?

In other words with such configuration we say for the indexing : U can use 10% of the heap but not more than all the heap?  
And then - what happens in between then?

can someone explain what happens when indexing heap usage exceeds 3.2 GB?

Thank you in advance.

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [January 1, 2018, 9:38pm UTC](https://discuss.elastic.co/t/indices-memory-index-buffer-size-documentation-is-ambiguous/110215/2 "2018-01-01T21:38:14Z")

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