Materializing internal computations in-memory to improve query performance

One or more non-transitory computer-readable media storing instructions which, when executed by one or more processors, cause:

• receiving, by a database server instance, a query;
• responsive to receiving the query, identifying, by the database server instance, a set of computations for evaluation during execution of the query;
• wherein the set of computations includes a first computation,
• where a result of executing the query is obtained from additionally evaluating at least a second computation that is different from the first computation in the set of computations;
• responsive to identifying the set of computations, evaluating the first computation, by the database server instance, to obtain a first set of computation results for the first computation, the first set of computation results being different from the result of executing the query;
• after evaluating the first computation, materializing, by the database server instance, within an in-memory unit in volatile storage managed by the database server instance, the first set of computation results for use during execution of another query;
• and
• storing, by the database server instance, within the in-memory unit, mapping data that maps a set of metadata values associated with the first computation to the first set of computation results, the set of metadata values including a reader count indicating how many processes are accessing the first set of computation results from the in-memory unit;
• using, by the database server instance, the first set of computation results, which were materialized within the in-memory unit, to answer a subsequently-received query that involves the first computation.