System and method for cardinality estimation based on query execution feedback
First Claim
Patent Images
1. A computer implemented method for estimating a cardinality of an expression, the method comprising:
- matching the expression with a stored expression;
retrieving previously gathered statistics associated with the stored expression, the previously gathered statistics comprising statistics based, at least in part, on a previous execution of a previous query; and
estimating the cardinality of the expression based on the previously gathered statistics.
2 Assignments
0 Petitions
Accused Products
Abstract
During query execution, statistics associated with expressions are observed. Such observed statistics preferably include the cardinality of each expression. The observed statistics are submitted to an expression manager as feedback from the executed query. The statistics are preferably stored for use in estimating the cardinality of execution plans for future queries.
-
Citations
20 Claims
-
1. A computer implemented method for estimating a cardinality of an expression, the method comprising:
-
matching the expression with a stored expression; retrieving previously gathered statistics associated with the stored expression, the previously gathered statistics comprising statistics based, at least in part, on a previous execution of a previous query; and estimating the cardinality of the expression based on the previously gathered statistics. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A computer readable medium having stored thereon computer readable instructions executed in a computer for performing the following steps:
-
matching an expression with a stored expression; retrieving previously gathered statistics associated with the stored expression, the previously gathered statistics comprising statistics based,-at least in part, on a previous execution of a previous query; and estimating a cardinality of the expression based on the previously gathered statistics. - View Dependent Claims (9, 10, 11, 12, 13, 14)
-
-
15. A computer implemented system for estimating a cardinality of an expression, the system comprising:
an expression manager for performing the steps of; matching the expression with a stored expression; and retrieving previously gathered statistics associated with the stored expression, the previously gathered statistics comprising statistics based, at least in part, on a previous execution of a previous query; and an optimizer for performing the step of estimating the cardinality of the expression based on the previously gather statistics. - View Dependent Claims (16, 17, 18, 19, 20)
Specification