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https://issues.apache.org/jira/browse/IMPALA-10723?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17523521#comment-17523521
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ASF subversion and git services commented on IMPALA-10723:
----------------------------------------------------------
Commit 8645ac6db39b30ba6b012b379c2295094e1b427b in impala's branch
refs/heads/master from Aman Sinha
[ https://gitbox.apache.org/repos/asf?p=impala.git;h=8645ac6db ]
IMPALA-11247: Test script changes for materialized views
IMPALA-10723 added support for treating materialized views as tables.
In certain test configurations, the rebuild of the materialized views
(which is done via Hive) was not populating the data in the MV. In
this patch, I have changed the source tables of materialized views
to be full-acid instead of insert-only transactional tables. This
enables the tests to succeed. Insert-only source tables are also
meant to work for the MV rebuild but that is a Hive issue that will
be investigated separately.
Change-Id: I349faa0ad36ec8ca6f574f7f92d9a32fb7d0d344
Reviewed-on: http://gerrit.cloudera.org:8080/18421
Reviewed-by: Aman Sinha <amsi...@cloudera.com>
Tested-by: Aman Sinha <amsi...@cloudera.com>
> Allow basic querying and computing stats on a materialized view
> ---------------------------------------------------------------
>
> Key: IMPALA-10723
> URL: https://issues.apache.org/jira/browse/IMPALA-10723
> Project: IMPALA
> Issue Type: Improvement
> Components: Frontend
> Reporter: Aman Sinha
> Assignee: Aman Sinha
> Priority: Major
> Fix For: Impala 4.1.0
>
>
> Currently, in Impala, a Materialized View (MV) created via Hive is visible
> through the metadata catalog and can be queried but the query is expanded to
> its corresponding view definition. This is incorrect because a materialized
> view is a regular (physical) table, not a view. Even though Impala does not
> support either creating MV or automatic rewriting to use MV, querying an MV
> directly should be allowed.
> Here's the current behavior:
> {noformat}
> [localhost:21050] functional> explain select * from materialized_view;
> Query: explain select * from materialized_view
> +------------------------------------------------------------------------------------+
> | Explain String
> |
> +------------------------------------------------------------------------------------+
> | Max Per-Host Resource Reservation: Memory=4.00MB Threads=2
> |
> | Per-Host Resource Estimates: Memory=10MB
> |
> | WARNING: The following tables are missing relevant table and/or column
> statistics. |
> | functional.insert_only_transactional_table
> |
> |
> |
> | PLAN-ROOT SINK
> |
> | |
> |
> | 01:EXCHANGE [UNPARTITIONED]
> |
> | |
> |
> | 00:SCAN HDFS [functional.insert_only_transactional_table]
> |
> | HDFS partitions=1/1 files=0 size=0B
> |
> | row-size=4B cardinality=0
> |
> +------------------------------------------------------------------------------------+
> {noformat}
> Note that the plan shows the scan of the underlying table instead of the
> materialized_view table. We should only be scanning the MV (including
> applying partition pruning, predicate pushdown etc.) and not treating this as
> a view.
> This JIRA is to enhance the frontend to recognize a materialized view as a
> table rather than a view. This will further allow commands such as COMPUTE
> STATS, DROP STATS, SHOW [TABLE | COLUMN] STATS to be run on the MV. One
> motivation for doing this is to allow an external frontend that supports
> automatic query rewrites using MVs to leverage the statistics on MVs.
> Since Impala is not creating the MV, we will need to block DML operations on
> the MV. Further, special handling needs to be done for Ranger authorization
> policies such that any column masking/row filtering policies defined on the
> source tables of the MV are taken into consideration.
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