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Registered: ‎09-26-2017

Kudu - deleting data

Hi I'm currently assessing Kudu to see if it has any advantages for my organisation. The ability to delete data is of particular interest, but i need to understand the delete process, and i can't find the information is any of the documentation i've read.

My question is:  Does the Kudu delete process remove data as part of the delete transaction as per an rdbms database solution would do, or does it mark the data for deletion(removing aaccess to it) like HBase would do.

 

Thanks

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Posts: 1,567
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Registered: ‎07-31-2013

Re: Kudu - deleting data

Deleted rows are not erased from disk synchronously with the operation, if I understand your question right - they are 'marked' and only truly erased from disk at the next RowSet compaction.

If you haven't yet, read https://kudu.apache.org/kudu.pdf (the section of interest is (4), "Tablet storage"), and https://github.com/apache/kudu/blob/master/docs/design-docs/tablet.md#mvcc-mutations-in-memrowset.

The latter link also compares Kudu with some other DB systems that use MVCC/etc., including Postgres, which you may find useful.
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