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US 2022/0012302 A1Published application
Selectivity estimation of conjunctive predicates
AssigneeSap SE
InventorsPeter Lysakovski, Guido Moerkotte, Norman May
Life of this patent
Estimating the term…
Abstract
A system includes determination of a query comprising z predicates, determination of known selectivities of each of a set of conjuncts of the z predicates, and estimation of selectivities of all conjuncts of the z predicates based on the known selectivities and a recursive determination of Cx, where x represents selectivities of all complete conjuncts of the z predicates and C is a complete design matrix complete design matrix (ci,j)=1 if i⊆j, else 0, having indices [0, 2z−1].
Claims15
A system comprising:
- a memory storing processor-executable program code;
- and
- a processing unit to execute the processor-executable program code in order to cause the system to:
- determine a query comprising z predicates;
- determine known selectivities of each of a set of conjuncts of the z predicates;
- and
- estimate selectivities of all conjuncts of the z predicates based on the known selectivities and a recursive determination of Cx,
- where x represents selectivities of all complete conjuncts of the z predicates and C is a complete design matrix
- (
- c
- i
- ,
- j
- )
- =
- {
- 1
- if
-
-
- i
- ⊆
- j
- 0
- els
-
- e
- ,
- having indices [0, 2z−1].
26 more elements
A computer-implemented method comprising:
- determining a query comprising z predicates;
- determining known selectivities of each of a set of conjuncts of the z predicates;
- and
- estimating selectivities of all conjuncts of the z predicates based on the known selectivities and a recursive determination of Cx,
- where x represents selectivities of all complete conjuncts of the z predicates and C is a complete design matrix
- (
- c
- i
- ,
- j
- )
- =
- {
- 1
- if
-
-
- i
- ⊆
- j
- 0
- els
-
- e
- ,
- having indices [0, 2z−1].
23 more elements
A database node comprising:
- a data source comprising a plurality of data rows;
- and
- a query processor to:
- determine a query on the data source comprising z predicates;
- determine known selectivities on the plurality of data rows of each of a set of conjuncts of the z predicates;
- and
- estimating selectivities on the plurality of data rows of all conjuncts of the z predicates based on the known selectivities and a recursive determination of Cx,
- where x represents selectivities of all complete conjuncts of the z predicates and C is a complete design matrix
- (
- c
- i
- ,
- j
- )
- =
- {
- 1
- if
-
-
- i
- ⊆
- j
- 0
- els
-
- e
- ,
- having indices [0, 2z−1].
26 more elements
Dependencies are inferred from the claim text.