After upgrading Elasticsearch from 6.6.2 to 7.13.4, we found the regex query is much slower(10 times slower).
We are doing a pretty expensive regex search like ".(["]fieldName["]:["]my-value-[A-Za-z][A-Za-z][A-Za-z0-9]["]).". But since we only have around 10 million documents for this index, it was working ok in version 6.6.2
Is there any known issues or any upgrade we missed in es 7.13.4?
Any suggestion is highly appreciated!