公开(公告)号：US20180039671A1

公开(公告)日：2018-02-08

申请号：US15783483

申请日：2017-10-13

Applicant: HUAWEI TECHNOLOGIES CO., LTD.

Inventor： Yidong YANG ,  Wenqi ZHU ,  Qing ZHANG ,  Li YAO ,  Zhongchu ZHU

IPC: G06F17/30

CPC classification number: G06F16/2456 ,  G06F16/24549 ,  G06F16/256 ,  G06F16/278

Abstract: The present invention discloses a method and an apparatus for querying data in cross-shard databases. The method includes: receiving a query request; querying statistics information of respective shard databases in which two tables used in an association operation are located; sending, according to the statistics information and the query condition, a driving table query request to a shard database in which a driving table is located, and receiving a first query result set returned by the shard database in which the driving table is located; deduplicating association field values in the first query result set, and sending a result set delivery request and deduplicated association field values to a shard database in which the non-driving table is located; and sending a non-driving table query request to the shard database; and receiving a second query result set returned by the shard database. Efficiency of querying data in cross-shard databases is improved.

公开(公告)号：US20200019552A1

公开(公告)日：2020-01-16

申请号：US16579209

申请日：2019-09-23

Applicant: HUAWEI TECHNOLOGIES CO., LTD.

Inventor： Yong DENG ,  Chenghua LIU ,  Yidong YANG ,  Wenqi ZHU

IPC: G06F16/2453 ,  G06F16/2455 ,  G06F11/34

Abstract: A query optimization method performed by a data access node includes: receiving a query request that is used to query tenant data; searching for a cached optimal query plan for the query request; if the optimal query plan is found, using the optimal query plan as a target query plan; or if no optimal query plan is found, generating a target query plan corresponding to the query request; and submitting the target query plan to a database, where the target query plan is used by the database to query the tenant data. Logical access (query request) is converted into a query plan (physical data access) by the data access node rather than a database node. In addition, the optimal query plan is used for query, so as to reduce a query cost as much as possible, and improve query performance.