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For HMS write, if validWriteIdList=null, HMS won’t cache the entry at all if this is managed table, and will cache regardless of validWriteIdList if this is external table. For HMS read, if validWriteIdList=null, HMS will return null if it is managed table, and return the cached entry regardless if it is external table(with eventual consistency model).
Thrift API will remain backward compatible for external table. That is, new server can deal with old client. If the old client issue a create_table call, server side will receive the request of create_table with validWriteIdList=null, and will cache or retrieve the entry regardless. For managed table, validWriteIdList will be required and HMS server will throw an exception if validWriteIdList=null (for both read and write).
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