599166320 commented on issue #12902: URL: https://github.com/apache/druid/issues/12902#issuecomment-1216310269
> How about using `APPROX_QUANTILE_DS` to calculate quantile? In most scenarios, we also use APPROX_QUANTILE_DS function to calculate the quantile value, and its intermediate results are also stored in the heap memory, with excellent performance. There are some problems with APPROX_QUANTILE_DS function. For example, the results are always floating around. Many customers cannot understand the principle and often need us to explain. There is also a maximum limit on the K value of Druid. If the K value is set too high, the performance will also be affected. Using Druid-histogram to calculate the quantile value also has some advantages, such as: the result is stable and will not float around. After knowing the range of data in advance, the calculation result is also accurate by setting a reasonable bucket. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
