Michael Smith has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/22738 )

Change subject: IMPALA-915: Cancel catalog ops for queries
......................................................................


Patch Set 12:

(2 comments)

http://gerrit.cloudera.org:8080/#/c/22738/12//COMMIT_MSG
Commit Message:

http://gerrit.cloudera.org:8080/#/c/22738/12//COMMIT_MSG@9
PS12, Line 9: Adds support to cancel metadata operations with catalogd by 
sending a
            : Cancel request to catalogd for the relevant query ID. Registers 
Java
            : Threads executing select catalog operations by their query ID.
> I am trying to understand what happens when a cancellation happens while th
Table loads can be interrupted, we have other exceptions that do that. I 
believe it leaves the table in an unloaded state.

If we do have multiple table loads in parallel initiated from the coordinator, 
they would all use the same query ID. That does break the 1-to-1 mapping of 
query ID to thread; we'd need to update Canceller to handle multiple threads 
per query ID.


http://gerrit.cloudera.org:8080/#/c/22738/12/be/src/service/client-request-state.cc
File be/src/service/client-request-state.cc:

http://gerrit.cloudera.org:8080/#/c/22738/12/be/src/service/client-request-state.cc@1551
PS12, Line 1551:   // Stop catalog operations on catalogd first since comms 
happen in the backend.
> Can't this lead to sending the cancel too early? For example:
That may be true. I think the risk of that is low.

It should be safe to swap the order so CancelExecRequest happens first; it's 
non-blocking.



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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: Iab22855bd2d63b64da008b52aa33230a6f422537
Gerrit-Change-Number: 22738
Gerrit-PatchSet: 12
Gerrit-Owner: Michael Smith <[email protected]>
Gerrit-Reviewer: Csaba Ringhofer <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Jason Fehr <[email protected]>
Gerrit-Reviewer: Joe McDonnell <[email protected]>
Gerrit-Reviewer: Michael Smith <[email protected]>
Gerrit-Reviewer: Quanlong Huang <[email protected]>
Gerrit-Reviewer: Riza Suminto <[email protected]>
Gerrit-Comment-Date: Wed, 09 Jul 2025 17:42:41 +0000
Gerrit-HasComments: Yes

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