Jibing-Li opened a new pull request, #26890: URL: https://github.com/apache/doris/pull/26890
backport https://github.com/apache/doris/pull/26435 Improve the accuracy of sample stats collection. For non distribution columns, use `n*d / (n - f1 + f1*n/N)` where `f1` is the number of distinct values that occurred exactly once in our sample of n rows (from a total of N), and `d` is the total number of distinct values in the sample. For distribution columns, use `ndv(n) * fraction of tablets sampled` for NDV. For very large tablet to sample, use limit to control the total lines to scan (for non key column only, because key column is sorted and will be inaccurate using limit). ## Proposed changes Issue Number: close #xxx <!--Describe your changes.--> ## Further comments If this is a relatively large or complex change, kick off the discussion at [[email protected]](mailto:[email protected]) by explaining why you chose the solution you did and what alternatives you considered, etc... -- 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]
