Pranay Singh has uploaded this change for review. ( http://gerrit.cloudera.org:8080/8215
Change subject: IMPALA-5142 EventSequence displays negative elapsed time. ...................................................................... IMPALA-5142 EventSequence displays negative elapsed time. EventSequence may display a negative elapsed time if ClientRequestState is done while EventSequence::MarkEvent() is in progress. The time is calculated based on POSIX clock_gettime() which uses CLOCK_MONOTONIC that will always give a time in increasing time order. In this case the cause of negative delay is start time becoming greater than end time, as the difference of latter and the former is used to compute the delay. The negative delay case can happen if EventSequence::Start() is called on the same EventSequence for which EventSequence::MarkEvent() is in progress.It can be serialized by reordering the lock in EventSequence::MarkEvent() but that may be a performance overhead, calling ElapsedTime() with lock held.So this patch fixes the issue by returning a 0 delay value when such an issue ever happens rather than returning a negative delay value. Testing: ------- Ran all the front-end/backend and end-end tests. Change-Id: I8c944396d96473b17b453da3e913ffc56680a896 --- M be/src/util/stopwatch.h 1 file changed, 6 insertions(+), 0 deletions(-) git pull ssh://gerrit.cloudera.org:29418/Impala-ASF refs/changes/15/8215/1 -- To view, visit http://gerrit.cloudera.org:8080/8215 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: newchange Gerrit-Change-Id: I8c944396d96473b17b453da3e913ffc56680a896 Gerrit-Change-Number: 8215 Gerrit-PatchSet: 1 Gerrit-Owner: Pranay Singh
