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HUE Clear Cache, Perform Incremental Metadata Update, Invalidate all Metadata and rebuild index

Hi,

I'm trying to understand a little more about what these options do behind the scenes when pressed?  I found this post, but it never got any responses (http://community.cloudera.com/t5/Web-UI-Hue-Beeswax/What-is-under-the-hood-of-Hue-Impala-editor-Clea...)

Clear Cache
This is the one I am not too sure what happens

Perform Incremental metadata Update
I assume this issues a refresh command for all tables within the current database which is been viewed?  If no database is veiwed does it do it for everything?

Invalidate All metadata and rebuild index
Same as above, but rather than refresh it invalidates full metadata?  If no database is veiwed does it do it for everything?

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Re: HUE Clear Cache, Perform Incremental Metadata Update, Invalidate all Metadata and rebuild index

> Clear Cache
> This is the one I am not too sure what happens

It appears to clear the cached entries within Hue frontend, so the metadata for assist and views is loaded again from its source (Impala, etc.). I don't see it calling a refresh on the tables, but it is possible I missed some implicit action.

> Perform Incremental metadata Update
> I assume this issues a refresh command for all tables within the current database which is been viewed? If no database is veiwed does it do it for everything?

This will compare HMS listing against Impala's for the DB in context and run specific "INVALIDATE METADATA [[db][.table]];" for the missing ones in Impala.

Yes, if no DB is in the context, it will equate to running a global "INVALIDATE METADATA;"

> Invalidate All metadata and rebuild index

This runs a plain "INVALIDATE METADATA;"