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From "Alex Behm (Code Review)" <ger...@cloudera.org>
Subject [Impala-ASF-CR] IMPALA-4172: Switch to BlockLocation methods for disk IDs
Date Fri, 04 Nov 2016 23:18:02 GMT
Alex Behm has posted comments on this change.

Change subject: IMPALA-4172: Switch to BlockLocation methods for disk IDs
......................................................................


Patch Set 1:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/4914/1/fe/src/main/java/org/apache/impala/catalog/HdfsTable.java
File fe/src/main/java/org/apache/impala/catalog/HdfsTable.java:

Line 379:   private static int getDiskId(String storageId) {
> could you go into detail about the performance problems?
In the BE we mod the disk id to determine which disk queue to put reads on, so I'm worried
about pathological cases with "collisions" where many ranges are assigned to only one disk
thread. That will be quite hard to debug.


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Gerrit-MessageType: comment
Gerrit-Change-Id: Ibbff94cef9a9db7b3945f8e7b0286866d2cc3b61
Gerrit-PatchSet: 1
Gerrit-Project: Impala-ASF
Gerrit-Branch: master
Gerrit-Owner: Laszlo Gaal <laszlo.gaal@cloudera.com>
Gerrit-Reviewer: Alex Behm <alex.behm@cloudera.com>
Gerrit-Reviewer: Laszlo Gaal <laszlo.gaal@cloudera.com>
Gerrit-Reviewer: Marcel Kornacker <marcel@cloudera.com>
Gerrit-Reviewer: Tim Armstrong <tarmstrong@cloudera.com>
Gerrit-HasComments: Yes

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