Beijing Oceanbase Technology Co., Ltd.

Oracle International Corporation

Ant Financial (hang Zhou) Network Technology Co., Ltd.

Yi Pan

Srikanth Bellamkonda

Bin Liu

Huang Yu

Yang Li

Zhiyong Jiang

Longzhong Wang

Yingying Yao

Madhuri Kandepi

Yi Xiao

Kavya Shankar

Dachuan Shen

Mingdou Tang

A method is provided to process a hierarchical query request for requesting to query a target database table, where the hierarchical query request includes a query start condition and a connection condition. The method includes: in a first query round, first data is queried from the target database table based on the query start condition, and the first data is used as a root node of a tree structure; a plurality of pieces of service data in the target database table are grouped into N data groups corresponding to N worker threads based on the connection condition, where N is an integer greater than 1; and in an iquery round greater than 1, a leaf node in the current tree structure is selected as a parent node; and a target worker thread corresponding to the parent node is determined from the N worker threads based on the connection condition.

Hierarchical query methods and apparatuses

Embodiments of this specification provide a table data query method, a table data query apparatus, and a system that are of a distributed database. In response to that a table data processing node executes a first execution subplan to read row data of a driving table, the table data query apparatus generates a data rescanning instruction or a data scanning instruction based on whether a cache apparatus of the table data processing node caches the read row data, and sends the data rescanning instruction or the data scanning instruction to a driven table scanning scheduling apparatus of the table data processing node. The driven table scanning scheduling apparatus obtains a driven table data query result based on the data rescanning instruction or the data scanning instruction, and returns the driven table data query result to the table data query apparatus.

Table data query of distributed database

A database query optimization computer-implemented method, medium, and system are disclosed. In one computer-implemented method, a data query request sent by a client device is received and parsed. An execution plan for executing the data query request is determined based on a parsing result. If the execution plan is a nested loop anti-join, whether there is a possibility that a to-be-queried field in a to-be-queried data table indicated by the data query request contains a NULL value is determined. If there is a possibility that the to-be-queried field contains a NULL value, a filter condition is generated and the execution plan is optimized based on the filter condition.

Database query optimization methods, apparatuses, and computer devices

Techniques herein improve computational efficiency for parallel queries with run-time data pruning by using adaptive granule generation. In an embodiment, an execution plan is generated for a query to be executed by a plurality of slave processes, the execution plan comprising a plurality of plan operators. For a first plan operator of the plurality of plan operators, a first set of work granules is generated, and for a second plan operator of the plurality of plan operators, a second set of work granules is generated. A first subset of slave processes of the plurality of slave processes is assigned the first set of work granules. Based on the execution of the first set of work granules by the first subset of slave processes, a bloom filter is generated that specifies for which of said first set of work granules no output rows were generated. Based on the bloom filter, the second set of work granules is modified and the modified second set of work granules is assigned to a second subset of slave processes and executed.

Adaptive granule generation for parallel queries with run-time data pruning

A method includes: obtaining, by an inner table node that stores a portion of an inner table, a portion of an outer table from each of outer table nodes, and wherein a size of the outer table is less than a size of the inner table; reading, by the inner table node, the outer table by table joining threads or table joining processes of the inner table node; matching, by the table joining threads or the table joining processes, the outer table with the portion of the inner table stored at the inner table node; and outputting, by the inner table node, data from the outer table and the portion of the inner table that matches with each other.

Method, apparatus, system, server, and storage medium for connecting tables stored at distributed database

According to embodiments, a multi-node database management system allows consumer processes ('consumers') implementing a portion of a distributed data-combination operation to independently send a STOP notification to corresponding producer processes ('producers'). Upon a given consumer determining that the consumer requires no further information from corresponding producers, the consumer sends a STOP notification to the producers. When a given consumer sends out a STOP notification, the producers drop any data destined for the given consumer and also stops preparing data for and sending rows to the given consumer. Furthermore, once the producers receive STOP notifications from all of the consumers corresponding to the producers, the producers stop the current sub plan execution immediately without requiring completion of the sub plan. Thus, embodiments significantly improve the query execution performance by avoiding scanning and distributing data that is not needed for execution of the distributed operation.

Growing community of inventors

Hangzhou, China

Yi Pan