Taras Bobrovytsky has uploaded a new patch set (#2). Change subject: IMPALA-4787: Optimize APPX_MEDIAN() memory usage ......................................................................
IMPALA-4787: Optimize APPX_MEDIAN() memory usage Before this change, ReservoirSample functions (such as APPX_MEDIAN()) allocated memory for 20,000 elements up front per grouping key. This caused inefficient memory usage for aggregations with many grouping keys. This patch fixes this by initially allocating memory for 20 elements. Once the buffer becomes full, we allocate room for 200 elements and copy the original buffer into the new one. We continue increasing the buffer size this way until the buffer has room for 20,000 elements as before. Testing: Ran BE and some relevant EE tests locally. No new tests were added, the existing tests should provide enough coverage. Change-Id: I99adaad574d4fb0a3cf38c6cbad8b2a23df12968 --- M be/src/exprs/aggregate-functions-ir.cc M testdata/workloads/functional-query/queries/QueryTest/alloc-fail-init.test 2 files changed, 136 insertions(+), 33 deletions(-) git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/25/6025/2 -- To view, visit http://gerrit.cloudera.org:8080/6025 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: newpatchset Gerrit-Change-Id: I99adaad574d4fb0a3cf38c6cbad8b2a23df12968 Gerrit-PatchSet: 2 Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-Owner: Taras Bobrovytsky <tbobrovyt...@cloudera.com> Gerrit-Reviewer: Alex Behm <alex.b...@cloudera.com> Gerrit-Reviewer: Matthew Jacobs <m...@cloudera.com> Gerrit-Reviewer: Taras Bobrovytsky <tbobrovyt...@cloudera.com>
