# Bulk index slowing down as index size increases

**URL:** <https://discuss.elastic.co/t/bulk-index-slowing-down-as-index-size-increases/234288>\
**Category:** Elasticsearch\
**Created:** [May 26, 2020, 9:16am UTC](https://discuss.elastic.co/t/bulk-index-slowing-down-as-index-size-increases/234288 "2020-05-26T09:16:12Z")\
**Posts on this page:** 1\
**Showing post:** 12

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**Author:** ![Pyppe](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/pyppe/32/3531_2.png) [@Pyppe](https://discuss.elastic.co/u/Pyppe)\
**Post date:** [May 27, 2020, 1:34pm UTC](https://discuss.elastic.co/t/bulk-index-slowing-down-as-index-size-increases/234288/12 "2020-05-27T13:34:10Z")

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Phew, I think I _finally_ found the root cause of the indexing speed slowing down. It's ICU4J transliteration, and the fact that after about 13.2M documents we start to have a lot of Chinese data.

I asked in a new post how to avoid duplicate transliterations (I am assuming the use of `icu_transform` in one property but with multiple fields results in running transliteration multiple times for the same identical text): [ICU transform filters slowing down indexing: how avoid duplicate transliterations?](https://discuss.elastic.co/t/icu-transform-filters-slowing-down-indexing-how-avoid-duplicate-transliterations/234547)

Thanks!

PS. @Christian_Dahlqvist feel free to continue with the good insights in the new post! 🙂

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