Bharath Vissapragada has posted comments on this change. Change subject: IMPALA-3680: Reset the file read offset for failed hdfs cache reads ......................................................................
Patch Set 2: (3 comments) http://gerrit.cloudera.org:8080/#/c/3313/1//COMMIT_MSG Commit Message: PS1, Line 12: re-issuing the whole set of scan ranges > Thanks. Can you incorporate this in the commit message or JIRA? Done Line 23: sped up with performance close to non-cached query runs. > I think we need a way to exercise this path in testing. For instance, the I think we can use IMPALA-3679 for this, where ZCRs are known to fail with caching in encryption zones. I wrote a simple test for this, let me know if you think its ok. http://gerrit.cloudera.org:8080/#/c/3313/1/be/src/runtime/disk-io-mgr-scan-range.cc File be/src/runtime/disk-io-mgr-scan-range.cc: Line 432: hdfsSeek(fs_, hdfs_file_->file(), offset_); > Regarding Open(), I was wondering why the call to Open() in DiskIoMgr::Read I didn't call Close() initially as it is heavier than hdfsSeek() but yea I agree with your point that it should undo all the side effects of Open(). Changed it now. -- To view, visit http://gerrit.cloudera.org:8080/3313 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: comment Gerrit-Change-Id: I0a9ea19dd8571b01d2cd5b87da1c259219f6297a Gerrit-PatchSet: 2 Gerrit-Project: Impala Gerrit-Branch: cdh5-trunk Gerrit-Owner: Bharath Vissapragada <[email protected]> Gerrit-Reviewer: Bharath Vissapragada <[email protected]> Gerrit-Reviewer: Dan Hecht <[email protected]> Gerrit-HasComments: Yes
