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From "John Sichi (JIRA)" <>
Subject [jira] Commented: (HIVE-972) support views
Date Thu, 14 Jan 2010 20:15:55 GMT


John Sichi commented on HIVE-972:

Some notes for reviewers:

(1) The reason I'm adding quoting for all identifiers (not just * expansion) during unparse
has to do with persistence.  Suppose today you create a table named units, and you create
a view select x from units.  Then tomorrow, you get a new version of hive in which units has
become a reserved word.  When we reparse the stored view definition, we'll get a parse error;
to avoid this, we store it as select `x` from `units` instead (regardless of whether you quoted
the identifiers in the initial CREATE VIEW statement).  The same goes for references to other
kinds of objects, so I'm attempting to future-proof it by doing it for functions as well (even
though today those aren't persistent); there seem to be some existing inconsistencies with
function name unescaping and lowercasing which I'm working through for the real patch submission.

(2) For regenerating thrift code, I used the archived r760184 version of thrift linked at  This gave the minimum number of diffs from the existing
generated code when compared with various other thrift versions I could find (but still a
few spurious ones).  After regeneration, I reverted files unrelated to my change.  At some
point, we should probably create a separate patch which brings our thrift generated code up
to date with more recent versions.

(3) I ended up putting the view text attributes on the Table class in the metastore, rather
than StorageDescriptor as proposed by Prasad.  In the future, if we need to track view definitions
associated with partitions, adding one more attribute to Partition should do the job.

(4) I'm not entirely sure what kind of metadata we want to store for view serde, inputFormat,
outputFormat, location, since this physical information isn't really relevant until we do
view materialization.  Take a look at the create_view.q.out DESCRIBE EXTENDED output to see
what's currently getting stored, and give me your feedback if you think changes are needed.

> support views
> -------------
>                 Key: HIVE-972
>                 URL:
>             Project: Hadoop Hive
>          Issue Type: New Feature
>          Components: Metastore, Query Processor
>            Reporter: Namit Jain
>            Assignee: John Sichi
>         Attachments: HIVE-972.1.patch
> Hive currently does not support views. 
> It would be a very nice feature to have.

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