A multi-dimensional OLAP query
processing method oriented to a column store
data warehouse is described. With this method, an OLAP query is divided into a
bitmap filtering operation, a group-by operation and an aggregate operation. In the
bitmap filtering operation, a predicate is first executed on a
dimension table to generate a predicate vector
bitmap, and a join operation is converted, through
address mapping of a
surrogate key, into a direct
dimension table tuple access operation; in the group-by operation, a
fact table tuple satisfying a filtering condition is pre-generated into a group-by unit according to a group-by attribute in an
SQL command and is allocated with an increasing ID; and in the aggregate operation, group-by aggregate calculation is performed according to a group item of a
fact table filtering group-by vector through one-pass column scan on a
fact table measure attribute.