Query Execution

Can I JOIN multiple sharded tables in a query?

Yes. SingleStoreDB Cloud supports advanced join capabilities and will automatically redistribute data as necessary to complete a query. SingleStoreDB Cloud can also take advantage of collocated data across shard keys and reference tables to reduce data movement. See Distributed Joins.

Can I optimize a distributed join involving a small, static table?

Yes, a small table which does not change frequently can be made into a reference table, which is replicated to all the leaf nodes. This ensures that the table does not need to be moved when joined against, at the cost of using more memory. See Distributed SQL.

Why do I get errors about UNIQUE KEYs?

SingleStoreDB Cloud does not support unique keys unless the columns in the unique key are a superset of the columns in the shard key. For more information about the shard key, see Sharding.

Why do I sometimes receive an ERROR 1227 when running a query?

The following error will be displayed if you do not have the requisite privileges to run a query:

ERROR 1227 ER_SPECIFIC_ACCESS_DENIED_ERROR: Access denied; you need (at least one of) the SUPER privilege(s) for this op

This error is expected for SingleStoreDB Cloud users when the query involves updating either global or engine variables. Please contact SingleStore Support if you need to update these variables.

If this error is encountered when running a query that does not involve global or engine variables, please contact SingleStore Support to help troubleshoot the cause.