https://community.cloudera.com/t5/Support-Questions/kudu-scan-very-slow/m-p/85498#M11687 <P>One thing that is clearly happening here is that Kudu is sending much more data than is necessary back to Impala. You specified LIMIT 7, but Kudu&nbsp;doesn't support server-side limits until CDH6.1. For such a small query, this might make things quite a bit faster.</P><P>&nbsp;</P><P>Beyond that, I honestly don't see anything suspicious about the numbers from the Kudu side other than the scan took a long time given the amount of work involved. The trace shows nothing out of the ordinary; the metrics are fine. There weren't even cache misses, so everything came out of cache decoded + decompressed.</P><P>&nbsp;</P><P>From the Impala profile, the only suspicious-looking thing is that two round trips were required. That shouldn't have been the case with LIMIT 7 as the first batch should have had more than 7 records in it.</P><P>&nbsp;</P><P>If you run the scan a couple times in a row, does it get much faster? How does the time vary with the LIMIT amount?</P> Fri, 25 Jan 2019 23:18:05 GMT wdberkeley 2019-01-25T23:18:05Z