Lars Volker has posted comments on this change. ( http://gerrit.cloudera.org:8080/12229 )
Change subject: IMPALA-7731: Add TxRatio counter to instances and query profile ...................................................................... Patch Set 1: (1 comment) http://gerrit.cloudera.org:8080/#/c/12229/1//COMMIT_MSG Commit Message: http://gerrit.cloudera.org:8080/#/c/12229/1//COMMIT_MSG@16 PS1, Line 16: by instances with a scan over the data read by all scans of the > Why do we only include the data transmitted from instances with scans? I th Yes, the one currently in this change is scan selectivity (and expansion of compressed data). For remote reads that would be the part of the network traffic that is driven by scans (exchange over the network / remote read over the network. The remainder of the traffic (between instances that don't have scans) should be negligible and when it is not, it could point towards a suboptimal execution tree and/or query that requires the whole data to be shuffled multiple times. Would you prefer exposing two disjoint ratios, e.g. ScanTxRatio and ExchangeTxRatio, the latter being "data between non-scan instances / data between scan instances". Large numbers would denote a potentially inefficient plan. I'm in favor of adding global counters. We already have TotalBytesRead from an earlier change and I'm happy to add TotalBytesExchanged. Do you think we should split TotalBytesRead up by storage, e.g. TotalBytesReadHdfs, TotalBytesReadKudu? -- To view, visit http://gerrit.cloudera.org:8080/12229 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Ife7ec78fe42558429c1cbe6e5eba79842bffd648 Gerrit-Change-Number: 12229 Gerrit-PatchSet: 1 Gerrit-Owner: Lars Volker <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Lars Volker <[email protected]> Gerrit-Reviewer: Philip Zeyliger <[email protected]> Gerrit-Comment-Date: Thu, 17 Jan 2019 21:41:15 +0000 Gerrit-HasComments: Yes
