# Side effect of decreasing index.translog.flush\_threshold\_size

**URL:** <https://discuss.elastic.co/t/side-effect-of-decreasing-index-translog-flush-threshold-size/70134>\
**Category:** Elasticsearch\
**Created:** [December 28, 2016, 11:03am UTC](https://discuss.elastic.co/t/side-effect-of-decreasing-index-translog-flush-threshold-size/70134 "2016-12-28T11:03:28Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Brad\_Jungsu\_Heo](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/brad_jungsu_heo/32/13135_2.png) [@Brad\_Jungsu\_Heo](https://discuss.elastic.co/u/Brad_Jungsu_Heo)\
**Post date:** [December 28, 2016, 11:03am UTC](https://discuss.elastic.co/t/side-effect-of-decreasing-index-translog-flush-threshold-size/70134/1 "2016-12-28T11:03:28Z")

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Hi.

In my test on my test cluster, after changing `index.translog.flush_threshold_size` from default 512MB (default) to 32MB, old gc occurs much less frequently. (I think this is because that the buffer is enoughly small, so that free'd Trans Log objects are collected in survivor area before moving to Old Gen.)

So, I will change `index.translog.flush_threshold_size` in my production cluster. But before that I'd like to know the side effect of small size of `index.translog.flush_threshold_size`.

I hope someone could help me.

I use ES 2.3.

Thanks.

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**Author:** ![ywelsch](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/ywelsch/32/7751_2.png) [@ywelsch](https://discuss.elastic.co/u/ywelsch)\
**Post date:** [December 28, 2016, 1:37pm UTC](https://discuss.elastic.co/t/side-effect-of-decreasing-index-translog-flush-threshold-size/70134/2 "2016-12-28T13:37:22Z")

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Having a smaller translog size will lead to more flushes, which means more frequent Lucene commits and thus more IO.

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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:** [January 25, 2017, 1:37pm UTC](https://discuss.elastic.co/t/side-effect-of-decreasing-index-translog-flush-threshold-size/70134/3 "2017-01-25T13:37:29Z")

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