Casey Ching has posted comments on this change.

Change subject: Simplify creating external Kudu tables and add DROP DATABASE 
CASCADE
......................................................................


Patch Set 9:

(1 comment)

http://gerrit.cloudera.org:8080/#/c/2617/9/fe/src/main/java/com/cloudera/impala/service/CatalogOpExecutor.java
File fe/src/main/java/com/cloudera/impala/service/CatalogOpExecutor.java:

Line 1121: The use of DdlDelegates combined with the fact that the catalog is 
disconnected
         :     // from the source of truth, the Hive metastore, leads to some 
complications here.
         :     // If 'db' is null, that should mean either the database doesn't 
really exist or the
         :     // database was created outside of Impala and the user didn't 
run "invalidate
         :     // metadata". If 'db' is not null, there still may be tables in 
the metastore that
         :     // would require a DdlDelegate. Another scenario is when the 
user creates tables
         :     // that reqire a DdlDelegate in Impala, then drops the database 
in Hive. Ideally the
         :     // user visible result of DROP DATABASE CASCADE would be the 
same in any case. The
         :     // best solution is probably to move the DdlDelegate 
functionality into Hive. For
         :     // now Impala will assume that any table not in its cache also 
doesn't require the
         :     // use of a DdlDelegate. If that assumption isn't correct, the 
database will still
         :     // be dropped in the metastore but the underlying data would 
remain. Users can issue
         :     // an REFRESH command to load the database metadata before 
dropping to ensure
         :     // delegates will be used when needed.
> I agree the code should make sense, but (a) this doesn't really explain the
This seems concise enough. The issue was created for tracking purposes. This 
comment explains why there isn't more code to handle the db == null case.


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Gerrit-MessageType: comment
Gerrit-Change-Id: Ic141102818b6dad3016181b179a14024d0ff709d
Gerrit-PatchSet: 9
Gerrit-Project: Impala
Gerrit-Branch: cdh5-trunk
Gerrit-Owner: Casey Ching <[email protected]>
Gerrit-Reviewer: Casey Ching <[email protected]>
Gerrit-Reviewer: Dimitris Tsirogiannis <[email protected]>
Gerrit-Reviewer: Marcel Kornacker <[email protected]>
Gerrit-Reviewer: Matthew Jacobs <[email protected]>
Gerrit-HasComments: Yes

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