Build a query execution pipeline from a query plan.

stop the operator.

Expression layer.

on-clause is FALSE.

on-clause is TRUE.

need to reopen child operator.

Execution layer.

Advisor() function.

context flags.

Server layer.

Sizer.

Dummy operator that simply wraps an item channel.

Enable copy-before-write, so that all reads use old values.

Collect subquery results.

Distincting of input data.

Grouping of input data.

Grouping of groups.

KeyScan is used for KEYS clauses (except after JOIN / NEST).

Receive subquery results This is a cross between Collect and Channel, where an executor gets documents on demand.

Send to keyspace.

Write to copy.

Write to copy.

ValueScan is used when there is a VALUES clause, e.g.