Zoltan Borok-Nagy has posted comments on this change. ( 
http://gerrit.cloudera.org:8080/24566 )

Change subject: IMPALA-15157: Parquet scanner reads non-existent page header 
when skipping to a page boundary
......................................................................


Patch Set 1: Code-Review+1

(2 comments)

Thanks for your contribution!

http://gerrit.cloudera.org:8080/#/c/24566/1//COMMIT_MSG
Commit Message:

http://gerrit.cloudera.org:8080/#/c/24566/1//COMMIT_MSG@7
PS1, Line 7: scanner reads non-existent page header when skipping to a page 
boundary
This implies failure/crash with the current logic, but what this patch actually 
does is a performance fix.

Current code: unnecessarily decompresses a page when it could be skipped
This patch: avoids unnecessary decompression

Is my understanding correct or am I missing something? If there is a real 
crash, please add a test that reproduces it. Or please update the commit 
message.


http://gerrit.cloudera.org:8080/#/c/24566/1/be/src/exec/parquet/parquet-column-readers.cc
File be/src/exec/parquet/parquet-column-readers.cc:

http://gerrit.cloudera.org:8080/#/c/24566/1/be/src/exec/parquet/parquet-column-readers.cc@1782
PS1, Line 1782:         if (num_rows == 0) {
> My understanding is that `num_rows` is the number of rows we want to skip.
Yes, correct.



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Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-MessageType: comment
Gerrit-Change-Id: I18f0e69c267c9bf041ff9f6a3d677239ae43971a
Gerrit-Change-Number: 24566
Gerrit-PatchSet: 1
Gerrit-Owner: Yifan Zhang <[email protected]>
Gerrit-Reviewer: Impala Public Jenkins <[email protected]>
Gerrit-Reviewer: Michael Smith <[email protected]>
Gerrit-Reviewer: Xuebin Su <[email protected]>
Gerrit-Reviewer: Zoltan Borok-Nagy <[email protected]>
Gerrit-Comment-Date: Fri, 10 Jul 2026 09:05:35 +0000
Gerrit-HasComments: Yes

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