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Jonathan Ellis commented on CASSANDRA-4734: ------------------------------------------- LGTM, +1. Nit: can we move validateConsistency into ModificationStatement so we don't need to duplicate it across delete/update? > Move CQL3 consistency to protocol > --------------------------------- > > Key: CASSANDRA-4734 > URL: https://issues.apache.org/jira/browse/CASSANDRA-4734 > Project: Cassandra > Issue Type: Task > Components: API > Reporter: Jonathan Ellis > Assignee: Sylvain Lebresne > Fix For: 1.2.0 beta 2 > > Attachments: 0001-Move-consistency-level-to-the-protocol-level-2.txt, > 0001-Move-consistency-level-to-the-protocol-level-3.txt, > 0001-Move-consistency-level-to-the-protocol-level.txt, > 0002-Remove-remains-of-4448-3.txt, 0002-Remove-remains-of-4448.txt, > 0002-Thrift-generated-file-diffs-2.txt, > 0003-Thrift-generated-file-diffs-3.txt, 0003-Thrift-generated-file-diffs.txt > > > Currently, in CQL3, you set the consistency level of an operation in > the language, eg 'SELECT * FROM foo USING CONSISTENCY QUORUM'. It now > looks like this was a mistake, and that consistency should be set at > the protocol level, i.e. as a separate parameter along with the query. > The reasoning is that the CL applies to the guarantee provided by the > operation being successful, not to the query itself. Specifically, > having the CL being part of the language means that CL is opaque to > low level client libraries without themselves parsing the CQL, which > we want to avoid. Thus, > - Those libraries can't implement automatic retries policy, where a query > would be retried with a smaller CL. (I'm aware that this is often a Bad > Idea, but it does have legitimate uses and not having that available is seen > as a regression from the Thrift api.) > - We had to introduce CASSANDRA-4448 to allow the client to configure some > form of default CL since the library can't handle that anymore, which is > hackish. > - Executing prepared statements with different CL requires preparing multiple > statements. > - CL only makes sense for BATCH operations as a whole, not the sub-statements > within the batch. Currently CQL3 "fixes" that by validating the given CLs > match, but it would be much more clear if the CL was on the protocol side. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira