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adampaul avatar image
adampaul asked ·

Read operation failure error, Scanned over 100001 tombstones

I have added bulk data , i am able to get count of rows but when i am executing select statement i am getting ReadFailure: Error from server: code=1300 [Replica(s) failed to execute read] message="Operation failed - received 0 responses and 1 failures" info={'failures': 1, 'received_responses': 0, 'required_responses': 1, 'consistency': 'ONE'}

when checking logs i found the warn message Scanned over 100001 tombstones during query 'SELECT * FROM test_keyspace.employee WHERE roll_no= 2200 AND () = () LIMIT 100' (last scanned row partion key was (25281)); query aborted

I have ran compaction still getting this much tombstone i have inserted null values i think this is reason of this what could be the best practice to avoid this .

tombstones
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1 Answer

Erick Ramirez avatar image
Erick Ramirez answered ·

This is expected behaviour because inserting null values generates tombstones.

You shouldn't insert null values since they are unnecessary in Cassandra. You can avoid this by calling the unset() method.

For details, see the Java driver documentation or question #2985 for the C# driver. Cheers!

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