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ASF GitHub Bot commented on DRILL-4726: --------------------------------------- Github user paul-rogers commented on a diff in the pull request: https://github.com/apache/drill/pull/574#discussion_r80578885 --- Diff: exec/java-exec/src/main/java/org/apache/drill/exec/planner/sql/handlers/DropFunctionHandler.java --- @@ -48,54 +48,77 @@ public DropFunctionHandler(SqlHandlerConfig config) { } /** - * Drops UDFs dynamically. + * Unregisters UDFs dynamically. Process consists of several steps: + * <ol> + * <li>Registering jar in jar registry to ensure that several jars with the same name is not being unregistered.</li> + * <li>Starts remote unregistration process, gets list of all jars and excludes jar to be deleted.</li> + * <li>Signals drill bits to start local unregistration process.</li> + * <li>Removes source and binary jars from registry area.</li> + * </ol> --- End diff -- Can we explain the semantics regarding in-flight queries? If query Q is executing while we unregister UDF U, what happens? Suppose user A submits query Q. The foreman for Q finds that Q uses UDF U. The rest of the prepare takes a while. At the same time, user B unregisters U (right after the Foreman for Q verified that U exists.) The Foreman for Q now sends fragments to other Drillbits. Should Q find that U is available on those Drillbits? Or, is it OK for Q to fail because at least one Drillbit has started to unregister U? Now, supppose that Drill queues are turned on and Q sits in the queue for a minute before executing. Should it still find that U is available on the various Drillbits? This all may be worked out, the point here is just to explain the intended behavior. > Dynamic UDFs support > -------------------- > > Key: DRILL-4726 > URL: https://issues.apache.org/jira/browse/DRILL-4726 > Project: Apache Drill > Issue Type: New Feature > Affects Versions: 1.6.0 > Reporter: Arina Ielchiieva > Assignee: Arina Ielchiieva > Fix For: Future > > > Allow register UDFs without restart of Drillbits. > Design is described in document below: > https://docs.google.com/document/d/1FfyJtWae5TLuyheHCfldYUpCdeIezR2RlNsrOTYyAB4/edit?usp=sharing > -- This message was sent by Atlassian JIRA (v6.3.4#6332)