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https://issues.apache.org/jira/browse/CASSANDRA-13819?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Joshua McKenzie updated CASSANDRA-13819:
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Component/s: Core
> Surprising under-documented behavior with DELETE...USING TIMESTAMP
> ------------------------------------------------------------------
>
> Key: CASSANDRA-13819
> URL: https://issues.apache.org/jira/browse/CASSANDRA-13819
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: Eric Wolak
> Priority: Minor
>
> While investigating differences between various Bigtable derivatives, I‘ve
> run into an odd behavior of Cassandra. I’m guessing this is intended
> behavior, but it's surprising enough to me that I think it should be
> explicitly documented.
> Let‘s say I have a sensor device reporting data with timestamps. It has a
> great clock, so I use its timestamps in a USING TIMESTAMP clause in my INSERT
> statements. One day Jeff realizes that we had a hardware bug with the sensor,
> and data before timestamp T is incorrect. He issues a DELETE...USING
> TIMESTAMP T to remove the old data. In the meantime, Sam figures out a way to
> backfill the data, and she writes a job to insert corrected data into the
> same table. In keeping with the schema, her job issues INSERT...USING
> TIMESTAMP statememts, with timestamps before T (because that’s the time the
> data points correspond to). When testing her job, Sam discovers that the
> backfilled data isn‘t appearing in the database! In fact, there’s no way for
> her to insert data with a TIMESTAMP <= T, because the tombstone written by
> Jeff several days ago is masking them. How can Sam backfill the corrected
> data?
> This behavior seems to match the HBase “Current Limitation” that Deletes Mask
> Puts, documented at http://hbase.apache.org/book.html#_deletes_mask_puts.
> Should the Cassandra docs also explicitly call-out this behavior?
> Related:
> http://thelastpickle.com/blog/2016/07/27/about-deletes-and-tombstones.html
> https://docs.datastax.com/en/cassandra/3.0/cassandra/dml/dmlAboutDeletes.html
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