Github user kkhatua commented on a diff in the pull request:
https://github.com/apache/drill/pull/1024#discussion_r149467572
--- Diff:
exec/jdbc/src/main/java/org/apache/drill/jdbc/impl/DrillCursor.java ---
@@ -376,6 +415,19 @@ synchronized void cleanup() {
currentBatchHolder.clear();
}
+ //Set the cursor's timeout in seconds
--- End diff --
We do get the timeout value from the Statement (Ref:
https://github.com/kkhatua/drill/blob/a008707c7b97ea95700ab0f2eb5182d779a9bcb3/exec/jdbc/src/main/java/org/apache/drill/jdbc/impl/DrillCursor.java#L372
)
However, the Statement is referred to by the ResultSet object as well, to
get a handle of the timer object. During testing, I found that there is a
possibility that the DrillCursor completes fetching all batches, but a slow
client would call ResultSet.next() slowly and time out. The ResultSet object
has no reference to the timer, except via the Statement object.
There is a bigger problem that this block of code fixes. During iteration,
we don't want to be able to change the timeout period. Hence, the DrillCursor
(invoked by the _first_ `ResultSet.next()` call) will be initialized and set
the timer to start ticking.Thereafter, any attempt to change the timeout can be
ignored.
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