# \#optimization

**URL:** https://discuss.dgraph.io/tag/optimization/107.md

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## [Slow query times for has() function (on play.dgraph.io)](https://discuss.dgraph.io/t/slow-query-times-for-has-function-on-play-dgraph-io/13826)

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**Author:** [@eugaia](https://discuss.dgraph.io/u/eugaia)\
**Replies:** 9\
**Last updated:** [April 26, 2021, 1:31pm UTC](https://discuss.dgraph.io/t/slow-query-times-for-has-function-on-play-dgraph-io/13826 "2021-04-26T13:31:44Z")

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I’ve been playing around with play.dgaph.io, and have noticed something odd with the has() function. Some requests return quickly, while others take almost 20 seconds to return. I’ve only tested this on play.dgraph.io s…

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## [cmSketch not benefitting from four rows](https://discuss.dgraph.io/t/cmsketch-not-benefitting-from-four-rows/8712)

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**Author:** [@diggy](https://discuss.dgraph.io/u/diggy)\
**Replies:** 18\
**Last updated:** [January 26, 2020, 11:56pm UTC](https://discuss.dgraph.io/t/cmsketch-not-benefitting-from-four-rows/8712 "2020-01-26T23:56:04Z")

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Moved from GitHub ristretto/108 Posted by FrankReh: I believe the commit f823dc4a broke the purpose of the cm sketch to have four rows. The bitwise-xor and mask are not creating the mix of indexes expected by the desig…