# Why shard failed exception is happening when trying to get a sub-string using scripetd fields?

**URL:** <https://discuss.elastic.co/t/why-shard-failed-exception-is-happening-when-trying-to-get-a-sub-string-using-scripetd-fields/158085>\
**Category:** Kibana\
**Created:** [November 25, 2018, 8:27am UTC](https://discuss.elastic.co/t/why-shard-failed-exception-is-happening-when-trying-to-get-a-sub-string-using-scripetd-fields/158085 "2018-11-25T08:27:49Z")\
**Posts on this page:** 1\
**Showing post:** 6

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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:** [November 26, 2018, 6:36am UTC](https://discuss.elastic.co/t/why-shard-failed-exception-is-happening-when-trying-to-get-a-sub-string-using-scripetd-fields/158085/6 "2018-11-26T06:36:59Z")

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You are still trying to use the field before checking that it exists. Have a look at [this thread](https://discuss.elastic.co/t/painless-if-two-field-exists-then-calculate/117489) for an example of how to do it.

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_[View the full topic](https://discuss.elastic.co/t/why-shard-failed-exception-is-happening-when-trying-to-get-a-sub-string-using-scripetd-fields/158085)._