A query processing system having a data manager, and a query manager also
includes a buffer. The query manager calls the data manager to access
data based on a query. Where there is no predicate check or consumption
operation on the record accessed, the data manager will notionally return
the record to the query manager. However, the data manager accomplishes
the return by writing the relevant portions of the record to a buffer.
The data manager maintains stabilization of the page containing the
record while the buffer is being written to. The data manager continues
to access records on the stabilized page and to write such records to the
buffer where appropriate. The query manager retrieves the records from
the buffer after the data manager has completed its operation resulting
from the query manager call.