公开(公告)号：US20240054132A1

公开(公告)日：2024-02-15

申请号：US18113154

申请日：2023-02-23

Applicant: Hitachi, Ltd.

Inventor： Mayuko OZAWA ,  Satoru WATANABE ,  Norifumi NISHIKAWA ,  Kazuhiko MOGI

IPC: G06F16/2455 ,  G06F16/22 ,  G06F11/34

CPC classification number: G06F16/2456 ,  G06F16/2255 ,  G06F11/3433

Abstract: The processing load for joining a plurality of tables by hash join is reduced for a computer system in which the CPU of a node creates a partial bloom filter that manages a first table hash value of a joining key of a row corresponding to a query in an assigned row of a build table. An integrated bloom filter is created from a plurality of partial bloom filters, and a second table hash value of the joining key of the row corresponding to the condition of the query among the rows of a probe table is calculated. The row of the probe table is transmitted to the node containing a row of the build table of the join hash value for that row when the integrated bloom filter includes an identical first table hash value, and an integrated joined table is created and returned to the query request source.

公开(公告)号：US20240303239A1

公开(公告)日：2024-09-12

申请号：US18369923

申请日：2023-09-19

Applicant: Hitachi, Ltd. ,  The University of Tokyo

Inventor： Norifumi NISHIKAWA ,  Shinji FUJIWARA ,  Mayuko OZAWA ,  Kazuhiko MOGI ,  Kazuo GODA ,  Yuto HAYAMIZU

IPC: G06F16/2453

CPC classification number: G06F16/24544

Abstract: The scanning range of an inner table can be limited in the join processing irrespective of the existence of search conditions or a partition key, and the performance of the join processing can be improved. There is a column range index representing a range of values stored in a table. When a join result of a current stage is an outer table related to a join of a next stage in a join of each stage of the join processing, a database management apparatus identifies whether there is a possibility that an inner table related to a join of a next stage includes a hit record in an inner table related to a join of a current stage based on a column range index corresponding to a join column of a current stage and a column range index corresponding to a join column of a next stage.

公开(公告)号：US20250110659A1

公开(公告)日：2025-04-03

申请号：US18830800

申请日：2024-09-11

Applicant: Hitachi, Ltd.

Inventor： Mayuko OZAWA ,  Norifumi NISHIKAWA ,  Yoshiki KUROKAWA ,  Kazuhiko MOGI

IPC: G06F3/06

Abstract: A data processing apparatus has a memory and a first storage apparatus and reads a data area from a second storage apparatus (a storage apparatus which is slower than the first storage apparatus and stores a plurality of data areas as data constituent elements). Regarding each processing block, the data processing apparatus determines whether an open/closed area for processing of a first processing block which is the processing block should be an entire area or a partial area of the data area, based on whether or not the data area which is input and/or output by the processing of the first processing block can also be accessed by processing of a second processing block which is a processing block other than the first processing block, and whether or not the second processing block is being executed.

公开(公告)号：US20240362192A1

公开(公告)日：2024-10-31

申请号：US18440999

申请日：2024-02-14

Applicant: Hitachi, Ltd.

Inventor： Yoshiki KUROKAWA ,  Toshihiko KASHIYAMA ,  Norifumi NISHIKAWA ,  Mayuko OZAWA ,  Kazuhiko MOGI

IPC: G06F16/182 ,  G06F16/14 ,  G06F16/172 ,  G06F16/18 ,  G06F16/188

CPC classification number: G06F16/1844 ,  G06F16/144 ,  G06F16/172 ,  G06F16/1865 ,  G06F16/188

Abstract: An update method in which a computer updates data stored in a first storage device by copying a plurality of files stored in the first storage device to a second storage device and writing the files updated in the second storage device back to the first storage device, the plurality of files constituting a part of a database. The update method includes a query determination for determining whether a query for requesting writing to one of the files stored in the second storage device is based on a cluster key of the database, low-frequency file identification for identifying a file having a low writing frequency among the files stored in the second storage device, and write-back for writing the file having the low writing frequency identified in the low-frequency file identification to the first storage device.