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All writes in Amazon MCS are stored durably and replicated three times across multiple AWS Availability Zones using LOCAL_QUORUM consistency. To help customers optimize performance and consistency, reads can be executed using either ONE, LOCAL_ONE or LOCAL_QUORUM consistency. Early in the preview, MCS would map unsupported consistency levels to supported levels to help customers migrate workloads without minimal changes to their source code. In this case, ONE was mapped to LOCAL_QUORUM. However, based on customer feedback, we have adjusted MCS to explicitly reject unsupported consistency levels to ensure there is no confusion about the consistency level being used.
You mentioned "can be executed using either ONE, LOCAL_ONE or LOCAL_QUORUM consistency". In that case why level ONE is not applicable for UPDATE command?
@cqlsh> CONSISTENCY;
Current consistency level is ONE.
@cqlsh> UPDATE ... SET ... WHERE ...;
InvalidRequest: Error from server: code=2200 [Invalid query] message="Consistency level ONE is not supported for this operation. Supported consistency levels are: LOCAL_QUORUM"
Is there a way to configure created keyspace/tables to default to level ONE? Update and Insert commands in provisioning scripts are failing because of default level.
Hey Dmitrijs - ONE is only supported for reads, not writes. Can you update your application to use LOCAL_QUORUM just for writes? Are you using ONE for performance? MCS will still offer single-digit write performance, even using LOCAL_QUORUM.
I've updated scripts and connector to use configurable consistency level. Thank you for answer!
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