Thomas Tauber-Marshall has posted comments on this change. Change subject: IMPALA-5416: Fix an impala-shell command recursion bug ......................................................................
Patch Set 2: (1 comment) http://gerrit.cloudera.org:8080/#/c/8063/2//COMMIT_MSG Commit Message: PS2, Line 12: The cause is that there is a "cmdqueue" member in cmd library, which is : used to execute commands not directly from user input. When impala-shell : reads a line with multiple commands, it splits the line into multiple : queries and insert them into the queue, and then gives control back to : the eventloop in cmd library. The problem is that a source command : calls execute_query_list(), which executes queries in the cmdqueue as : well. So any query in the cmdqueue will be executed twice. And if there : is unfortunately a source command in the cmdqueue, it will call : execute_query_list() again, and there will be an infinite recursion. : The original purpose of running queued queries in execute_query_list() : is that in non-interactive mode, there is no event loop. And still, : there are queries like "use database" queued by connection setup : procedures, which need to be run before the user query. : This patch avoids running queries from the queue in : execute_query_list(), and for non-interactive mode, runs queued queries : in execute_queries_non_interactive_mode() instead. Thanks for the explanation. Hate to be picky, but this is more technical detail than I was looking for. The idea here is to give the reader a high level idea of what's going on while keeping it simple. Maybe something like (assuming I understand completely): The cmdqueue member of cmd.Cmd is used to execute commands not directly from user input in an event loop. When a 'source' is run, execute_query_list() is called which also executes the commands in cmdqueue, causing them to be executed twice. The fix is for execute_query_list() to not run the commands in cmdqueue. For the non-interactive case, where the event loop won't be run, we call execute_query_list() with cmdqueue so that the commands get run. -- To view, visit http://gerrit.cloudera.org:8080/8063 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-MessageType: comment Gerrit-Change-Id: I453af2d4694d47e184031cb07ecd2af259ba20f3 Gerrit-PatchSet: 2 Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-Owner: Tianyi Wang <tw...@cloudera.com> Gerrit-Reviewer: Thomas Tauber-Marshall <tmarsh...@cloudera.com> Gerrit-Reviewer: Tianyi Wang <tw...@cloudera.com> Gerrit-HasComments: Yes
