| US 7,516,117 B2 | ||
| Method for accelerating range queries using periodic monotonic properties of non-monotonic functions | ||
| Bishwaranjan Bhattacharjee, Yorktown Heights, N.Y. (US); Timothy Ray Malkemus, Round Rock, Tex. (US); and Ioana Roxana Stanoi, White Plains, N.Y. (US) | ||
| Assigned to International Business Machines Corporation, Armonk, N.Y. (US) | ||
| Filed on Aug. 24, 2006, as Appl. No. 11/509,050. | ||
| Prior Publication US 2008/0059410 A1, Mar. 06, 2008 | ||
| Int. Cl. G06F 7/00 (2006.01); G06F 17/30 (2006.01) | ||
| U.S. Cl. 707—2 [707/3] | 1 Claim |

| 1. A computer implemented method for accelerating range queries using monotonic properties of non-monotonic functions, comprising:
at least one processor for executing the steps of:
mapping a base column x to an existing index on a column y that is correlated with column x through a piecewise monotonic
function F(x);
rewriting an index construction statement to force the existing index on column y to track a piecewise monotonic property
by assigning identical values of F(x) to different periods to different ranges to create an annotated index;
rewriting range queries over the annotated index on F(x) by modifying a derived predicate,
constructing said existing index;
wherein said constructing said existing index comprises:
recognizing said piecewise monotonic function and a periodicity of said piecewise monotonic function; and
building an index over the monotonic function,
wherein said recognizing said piecewise monotonic function is accomplished from explicit user input, recognizing semantically
that a function is known to be a piecewise monotonic function and verifying a relationship between values of the base column
x and an a derived column, and
wherein during said building an index over the monotonic function if a derived column is known to be a monotonic function
by observation, at each of a plurality of updates a relationship should be verified.
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