Jim Apple has posted comments on this change.

Change subject: IMPALA-2840: Don't store table location in partition location
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Patch Set 5:

(7 comments)

http://gerrit.cloudera.org:8080/#/c/2355/5/be/src/runtime/descriptors.cc
File be/src/runtime/descriptors.cc:

Line 38: namespace
> Out of curiosity, why don't you put this function under impala namespace?
To keep from polluting the namespace (when linking, since during compiling it 
would be invisible whether in impala:: or an unnamed namespace.


Line 41: // format that references the 'partition_prefixes' of 'thrift_table'.
> Can you also comment on the return value when location isn't set?
Done


http://gerrit.cloudera.org:8080/#/c/2355/5/common/thrift/CatalogObjects.thrift
File common/thrift/CatalogObjects.thrift:

Line 223: HDFS partition's location
> There is no reason why we can't use this to compress other locations as wel
Done in HdfsPartitionLocationCompressor.java class comment.


http://gerrit.cloudera.org:8080/#/c/2355/5/fe/src/main/java/com/cloudera/impala/catalog/HdfsPartitionLocationCompressor.java
File 
fe/src/main/java/com/cloudera/impala/catalog/HdfsPartitionLocationCompressor.java:

Line 28: This class is not thread-safe. Clients of this class need to protect 
against
       :  * concurrent updates using external locking.
       :  *
       :  * Owned by HdfsTable instance.
> Since this is owned by HdfsTable and the catalog uses table-level locking, 
Done


Line 35: numClusteringColumns_
> This doesn't seem to be used anywhere besides getter and setter. Why storin
It is also used in decomopose().


Line 39: indexToPrefix
> This is a bit misleading as it sort of indicates that this is a map. Maybe 
Changed to use ListMap, an Impala-specific bidi map from T to int/Integer and 
back.


Line 88: public class Location
> How about the following idea for organizing this code:
What I don't like about this is that it spreads the compression code out into 
three different places.

One thing we could do, once we start using prefix compression in more than one 
place, is make this class more generic, parameterizing by an interface that has 
a decompose method.

I'd prefer to roll that up into the TODO at the top of this class about using 
this compression method for other sets of Strings that are likely to share 
prefixes. What do you think?


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Gerrit-MessageType: comment
Gerrit-Change-Id: I8c67b6ce0f83de2f5277a528a9ce67e47d638adb
Gerrit-PatchSet: 5
Gerrit-Project: Impala
Gerrit-Branch: cdh5-trunk
Gerrit-Owner: Jim Apple <[email protected]>
Gerrit-Reviewer: Dimitris Tsirogiannis <[email protected]>
Gerrit-Reviewer: Jim Apple <[email protected]>
Gerrit-Reviewer: Marcel Kornacker <[email protected]>
Gerrit-Reviewer: Sailesh Mukil <[email protected]>
Gerrit-HasComments: Yes

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