[Koha] Elastic 7, slow searches

[Björn Nylén]

Hi!

Has anyone had expeience with slow searches when upgrading ES to 7?

We were thinking ofjumping straight to 7.x from 5.x for our elastic server.
There is a few mod needed in th search query but nothing big. However we're noting quite a big slowdown i search speed, especially for wildcard querys. If we do a "*" search we se a change from ca 5s on the old to ca 12s on the es7 server but also "regular" searches are slower as well but not as apparent.

Our db contains about 2.6M bibs so fairly large but it shouldn't be muck of a problem for ES. Tried throwing cpu and ram on the problem with little success. (We also have a smaller testservers that handle the index/db/webserver on its own so hw shouldn't be the problem)  Tried various number of shards, but 5 seems to be a good place.  Also made sure paging is off.


Any input appreciated!

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Regards
Björn Nylén
Lund University Library