Extraction method, extraction device, and extraction program
AssigneeNippon Telegraph and Telephone Corporation
InventorYuya WATARI
Life of this patent
Estimating the term…
Abstract
An extraction apparatus (10) is the extraction apparatus that extracts a common plan subtree that is a common part among a plurality of plan trees from the plurality of plan trees, and includes a first assignment unit (11) that calculates, based on information of nodes of a plan tree, a hash value for each node to assign the calculated hash value to the corresponding each node, a second assignment unit (12) that assigns a unique number associated with a set of pointers to each node based on the hash value of each node, and a common plan subtree extraction unit (13) that lists subtrees below a node having the same unique number to extract the common plan subtree from the plurality of plan trees.
Claims6
An extraction method executed by an extraction apparatus, the extraction apparatus being configured to extract a common plan subtree that is a common part among a plurality of plan trees from the plurality of plan trees, the extraction method comprising:
- calculating, based on pieces of information of nodes of a plan tree of the plurality of plan trees, a hash value for each of the nodes to assign the calculated hash value to the corresponding each of the nodes;
- assigning a unique number associated with a set of pointers to each of the nodes based on the hash value of each of the nodes;
- and
- listing subtrees below a node of the nodes having the unique number identical, to extract the common plan subtree from the plurality of plan trees.
An extraction apparatus configured to extract a common plan subtree that is a common part among a plurality of plan trees from the plurality of plan trees, the extraction apparatus comprising:
- first assignment circuitry configured to calculate, based on pieces of information of nodes of a plan tree of the plurality of plan trees, a hash value for each of the nodes to assign the calculated hash value to the corresponding each of the nodes;
- second assignment circuitry configured to assign a unique number associated with a set of pointers to each of the nodes based on the hash value of each of the nodes;
- and
- extraction circuitry configured to list subtrees below a node of the nodes having the unique number identical, to extract the common plan subtree from the plurality of plan trees.
A non-transitory computer readable medium storing a program configured to cause a computer to execute:
- calculating, for a plurality of plan trees, based on pieces of information of nodes of a plan tree of the plurality of plan trees, a hash value for each of the nodes to assign the calculated hash value to the corresponding each of the nodes;
- assigning a unique number associated with a set of pointers to each of the nodes based on the hash value of each of the nodes;
- and
- listing subtrees below a node of the nodes having the unique number identical, to extract a common plan subtree from the plurality of plan trees, the common plan subtree being a common part among the plurality of plan trees.
Dependencies are inferred from the claim text.