# The necessity of translog in the writing process of elasticSearch

**URL:** <https://discuss.elastic.co/t/the-necessity-of-translog-in-the-writing-process-of-elasticsearch/379769>\
**Category:** Elasticsearch\
**Created:** [July 3, 2025, 2:03pm UTC](https://discuss.elastic.co/t/the-necessity-of-translog-in-the-writing-process-of-elasticsearch/379769 "2025-07-03T14:03:00Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ka\_ka](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/ka_ka/32/143984_2.png) [@ka\_ka](https://discuss.elastic.co/u/ka_ka)\
**Post date:** [July 3, 2025, 2:03pm UTC](https://discuss.elastic.co/t/the-necessity-of-translog-in-the-writing-process-of-elasticsearch/379769/1 "2025-07-03T14:03:00Z")

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What are the advantages of using the translog compared to simply setting a very low flush interval? If I set the flush interval to be very low, wouldn't that also achieve persistence? (I realize this might be a bit of a nitpicky question, but I'm curious about the difference.)

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**Author:** ![Christian\_Dahlqvist](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/christian_dahlqvist/32/4617_2.png) [@Christian\_Dahlqvist](https://discuss.elastic.co/u/Christian_Dahlqvist)\
**Post date:** [July 3, 2025, 2:11pm UTC](https://discuss.elastic.co/t/the-necessity-of-translog-in-the-writing-process-of-elasticsearch/379769/2 "2025-07-03T14:11:59Z")

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Flushing is a quite expensive operation, which can be seen in the guide for [optmizing indexing speed](https://www.elastic.co/docs/deploy-manage/production-guidance/optimize-performance/indexing-speed) where it is recommended to increase the refresh interval in order to gain indexing throughput. Writing to the transaction log has a lot less overhead. If there was no transaction log you would either end up with lack of persistence guarantees or very small segments, both which are very bad.