| US 7,555,473 B2 | ||
| Partial pre-aggregation in relational database queries | ||
| Per-Ake Larson, Redmond, Wash. (US); and Cesar A. Galindo-Legaria, Redmond, Wash. (US) | ||
| Assigned to Microsoft Corporation, Redmond, Wash. (US) | ||
| Filed on Mar. 17, 2005, as Appl. No. 11/82,392. | ||
| Application 11/082392 is a continuation of application No. 09/608395, filed on Jun. 30, 2000, granted, now 7,133,858. | ||
| Prior Publication US 2005/0240556 A1, Oct. 27, 2005 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. G06F 17/30 (2006.01); G06F 7/00 (2006.01) | ||
| U.S. Cl. 707—3 [707/2] | 12 Claims |
| 1. One or more computer-readable media comprising computer-executable instructions for processing a database query, the computer-executable
instructions comprising instructions for:
estimating costs and benefits of a partial pre-aggregation, wherein an estimate of a number of records that would be output
from the partial pre-aggregation is based on a formula having inputs comprising; a memory space for group records, M; a number
of input records, N, N being greater than a number, D, of records after full aggregation; and an absorption power term, wherein
the absorption power term comprises a summation of D terms, each term including a probability of a record belonging in a group
of records;
if indicated by the estimate, partially pre-aggregating records in a database according to a single grouping column to provide
a result that contains at least two records having like grouping column values; and
aggregating records derived from the partial pre-aggregation to provide a result that contains records having unique grouping
column values.
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