Queries

You can identify the average time that it takes to run a query against the distributed key value data store through the specific DDS service, the total number of successful queries, and the total number of queries that failed because of a timeout issue.

You might want to review query information to monitor the health of the key data store, Cassandra, which impacts the system’s ingest and retrieval performance. For example, if the latency for an average query is slow and the number of failed queries due to timeouts is high, the data store might be encountering a higher load or performing another operation.

You can also view the total number of queries that failed because of consistency failures. Consistency level failures result from an insufficient number of available distributed key value stores at the time a query is performed through the specific DDS service.

Consistency guarantees and controls

StorageGRID Webscale guarantees read-after-write consistency for newly created objects. Any GET operation following a successfully completed PUT operation will be able to read the newly written data. Overwrites of existing objects, metadata updates, and deletes remain eventually consistent.