It is likely that the implementation of StoreCostController will open the conglomerate and will leave the conglomerate open until the StoreCostController is closed. This represents a significant amount of work, so the caller if possible should attempt to open the StoreCostController once per unit of work and rather than close and reopen the controller. For instance if the optimizer needs to cost 2 different scans against a single conglomerate, it should use one instance of the StoreCostController.
The locking behavior of the implementation of a StoreCostController is undefined, it may or may not get locks on the underlying conglomerate. It may or may not hold locks until end of transaction. An optimal implementation will not get any locks on the underlying conglomerate, thus allowing concurrent access to the table by a executing query while another query is optimizing.
@see TransactionController#openStoreCost @see RowCountable
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