Wenzhe Zhou has uploaded this change for review. ( http://gerrit.cloudera.org:8080/15167
Change subject: IMPALA-8759: Use double precision for HLL finalize function ...................................................................... IMPALA-8759: Use double precision for HLL finalize function Current HLL finalize function use single precision of data type float32 to calculate estimate. It's not accurate for the larger cardinalities beyond 1,000,000 since float32 only has 6~7 decimal digit precision. This patch change single precision data type to double precision type for HLL finalize function. Testing: - Passed all exhaustive tests. - Did benchmark for queries with NDV functions. The performance impact is negligible. Change-Id: I0c5a5229b682070b0bc14da287db5231159dbb3d --- M be/src/exprs/aggregate-functions-ir.cc 1 file changed, 9 insertions(+), 9 deletions(-) git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/67/15167/3 -- To view, visit http://gerrit.cloudera.org:8080/15167 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: newchange Gerrit-Change-Id: I0c5a5229b682070b0bc14da287db5231159dbb3d Gerrit-Change-Number: 15167 Gerrit-PatchSet: 3 Gerrit-Owner: Wenzhe Zhou <wz...@cloudera.com> Gerrit-Reviewer: Bikramjeet Vig <bikramjeet....@cloudera.com> Gerrit-Reviewer: Tim Armstrong <tarmstr...@cloudera.com>
