Alexey Serbin has posted comments on this change. ( http://gerrit.cloudera.org:8080/17773 )
Change subject: KUDU-1260: Fix prefetching bug on Java scanner ...................................................................... Patch Set 9: (3 comments) http://gerrit.cloudera.org:8080/#/c/17773/9//COMMIT_MSG Commit Message: http://gerrit.cloudera.org:8080/#/c/17773/9//COMMIT_MSG@20 PS9, Line 20: consecutive Did you mean concurrent (instead of consecutive)? There might be any number of consecutive scan requests sent to a tablet server. http://gerrit.cloudera.org:8080/#/c/17773/9//COMMIT_MSG@20 PS9, Line 20: Furthermore, there are at most two consecutive ScanRequests : sent to the tserver. But if the scan data reached the end, only one hasMore=false is returned. : As a result, one of the ScanRequests got "scanner not found (it may have expired)" exception. : The same issue occurs for KeepAliveRequest. : This error may cause the spark task to fail sometimes. It seems allowing two concurrent ScanRequests brings in troubles. Instead of implementing these workarounds which might hide some real issues, is it possible to change the implementation to avoid sending multiple concurrent scan requests to a server? http://gerrit.cloudera.org:8080/#/c/17773/9/java/kudu-client/src/main/java/org/apache/kudu/client/AsyncKuduScanner.java File java/kudu-client/src/main/java/org/apache/kudu/client/AsyncKuduScanner.java: http://gerrit.cloudera.org:8080/#/c/17773/9/java/kudu-client/src/main/java/org/apache/kudu/client/AsyncKuduScanner.java@308 PS9, Line 308: public Could this method be private or package private instead? -- To view, visit http://gerrit.cloudera.org:8080/17773 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: kudu Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I853a041d86c75ec196d7d4ff45af4673c5c5f5cd Gerrit-Change-Number: 17773 Gerrit-PatchSet: 9 Gerrit-Owner: Hongjiang Zhang <[email protected]> Gerrit-Reviewer: Alexey Serbin <[email protected]> Gerrit-Reviewer: Grant Henke <[email protected]> Gerrit-Reviewer: Hongjiang Zhang <[email protected]> Gerrit-Reviewer: Kudu Jenkins (120) Gerrit-Comment-Date: Tue, 07 Sep 2021 06:47:09 +0000 Gerrit-HasComments: Yes
