Fang-Yu Rao has posted comments on this change. ( http://gerrit.cloudera.org:8080/20669 )
Change subject: IMPALA-3268: Add support for SHOW VIEWS statement ...................................................................... Patch Set 9: (1 comment) I slightly revised the commit message of patch set 8 to address Michael's comment regarding the differences between the 2 startup flags of the catalog server. Let me know if there are additional suggestions. Thanks! http://gerrit.cloudera.org:8080/#/c/20669/6//COMMIT_MSG Commit Message: http://gerrit.cloudera.org:8080/#/c/20669/6//COMMIT_MSG@14 PS6, Line 14: always load the table type of each Tab > I'm not really clear on the difference between these two options. When woul Thanks Michael! I am not familiar with the differences between these 2 flags. But by attaching a debugger to the Impala coordinator when executing the command "show views in functional", I found that "--pull_table_types_and_comments=true" is a more lightweight flag. Specifically, if the catalog server is started with "--pull_table_types_and_comments=true", then before a Table, e.g., 'functional.materialized_view', is referenced by a query, this Table will be an instance of IncompleteTable, where a lot of table metadata is not loaded, whereas with "--load_catalog_in_background=true", the same Table will be an instance of MaterializedViewHdfsTable with fully loaded table metadata from Hive MetaStore. As to where to set a break point, one possible place is https://gerrit.cloudera.org/c/20669/8/fe/src/main/java/org/apache/impala/catalog/Db.java#217. Recall that 'tableCache_.metadataCache_' is a Map from table names to Table's. We will be able to inspect the instance of a Table at runtime there. On the other hand, I also found the documentation of the flag '--load_catalog_in_background=true' at https://impala.apache.org/docs/build/html/topics/impala_config_options.html#:~:text=If%20set%20to%20true,service%20and%20Impala%20Daemon. although we do not elaborate on the differences between these 2 flags there. -- To view, visit http://gerrit.cloudera.org:8080/20669 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I321fc5350392a815949a4e7d2a64d60466689788 Gerrit-Change-Number: 20669 Gerrit-PatchSet: 9 Gerrit-Owner: Fang-Yu Rao <[email protected]> Gerrit-Reviewer: Aman Sinha <[email protected]> Gerrit-Reviewer: Fang-Yu Rao <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Michael Smith <[email protected]> Gerrit-Reviewer: Quanlong Huang <[email protected]> Gerrit-Reviewer: Sai Hemanth Gantasala <[email protected]> Gerrit-Comment-Date: Thu, 30 Nov 2023 00:06:55 +0000 Gerrit-HasComments: Yes
