| CPC G06F 16/24544 (2019.01) [G06F 16/24539 (2019.01)] | 14 Claims |
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1. A data processing device comprising a processor configured to execute an operation comprising:
memory storing instructions that, when executed by the processor, causes the device to perform a set of operations, the set of operations comprising:
recording, as a history of a plan tree of each issued query, an execution result of the plan tree, a history of specific information for specifying each node of the plan tree, and an appearance frequency at which the plan tree has appeared in a past; and
obtaining specific information corresponding to an execution plan being executed, wherein use of the specific information is associated with:
referring to the history of the plan tree by using the obtained specific information as a key, and
reusing the execution result of the plan tree of the obtained specific information when the obtained specific information exists,
extracting a common partial plan tree, wherein the common partial plan tree includes a common part of each plan tree from the plan tree of each issued query,
assigning specific information to each node of the common partial plan tree,
referring to the history and the appearance frequency of the specific information, and
caching the common partial plan tree, wherein the common partial plan tree has appeared a number of times equal to or greater than a predetermined appearance frequency threshold among a plurality of common partial plan trees.
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