Internal tables for accessing data stored in a database

Patent metadata

Field	Value
Publication number	US-2020034463-A1
Application number	US-201816174824-A
Country	US
Kind code	A1
Filing date	Oct 30, 2018
Priority date	Jul 26, 2018
Publication date	Jan 30, 2020
Grant date	—

Abstract

A method for transferring data from a database may include receiving, at a database management system, a request to transfer, to a client, at least a portion of data stored at a database coupled with the database management system. The database management system may respond to the request by at least generating an internal table containing at least the portion of the data being transferred to the client. The database management system may further transfer at least the portion of the data to the client by at least sending, to the client, one or more data chunks. Each of the one or more data chunks may include at least a portion of a column of data from the internal table. Related systems and articles of manufacture, including computer program products, are also provided.

First claim

What is claimed is:

1 . A system, comprising:
at least one data processor; and at least one memory storing instructions which, when executed by the at least one data processor, result in operations comprising:
receiving, at a database management system, a request to transfer, to a client, data stored at a database coupled with the database management system;
responding to the request by at least generating an internal table containing the data being transferred to the client; and
transferring the data to the client by at least sending, to the client, one or more data chunks, each of the one or more data chunks including at least a portion of a column of data from the internal table, and each of the one or more data chunks including at least a portion of a dictionary and/or an index based at least on the request indicating that the data transferred to the client is to be compressed.

2 . The system of claim 1 , wherein at least some of the one or more data chunks include a value array comprising the column of data from the internal table based at least on the request indicating that the data transferred to the client is to be uncompressed.

3 . The system of claim 1 , further comprising:
compressing the column of data by at least generating a dictionary and an index, the dictionary enumerating one or more unique values appearing in the column of data, and the index identifying one or more rows occupied by each of the one or more unique values.

4 . The system of claim 3 , wherein the dictionary comprises a global dictionary enumerating every unique value that appear in the column of data.

5 . The system of claim 4 , wherein the one or more data chunks include a first data chunk and a second data chunk, wherein the first data chunk includes at least a portion of the global dictionary, and wherein the second data chunk includes at least a portion of the index.

6 . The system of claim 3 , wherein the dictionary comprises a first local dictionary and a second local dictionary, wherein the first local dictionary enumerates unique values appearing in a first data chunk from the one or more data chunks, and wherein the second local dictionary enumerates unique values appearing in a second data chunk from the one or more data chunks.

7 . The system of claim 6 , wherein the first data chunk includes the first local dictionary and a first index identifying rows occupied by the unique values enumerated in the first local dictionary, and wherein the second data chunk includes the second local dictionary and a second index identifying rows occupied by the unique values enumerated in the second local dictionary.

8 . The system of claim 1 , wherein a first data chunk and a second data chunk from the one or more data chunks include data from a first column of data in the internal table, wherein a third data chunk from the one or more data chunks includes data from a second column of data in the internal table, and wherein the third data chunk is sent to the client prior to the second data chunk in order to enable a formation of a complete row of data from the internal table.

9 . The system of claim 1 , wherein a data chunk is sent to the client upon determining that the data chunk is full.

10 . The system of claim 1 , wherein the request comprises a structured query language (SQL) query and/or an invocation of a stored procedure at the database management system, and wherein at least the portion of the data comprises a projection of one or more tables stored at the database.

11 . A computer-implemented method, comprising:
receiving, at a database management system, a request to transfer, to a client, data stored at a database coupled with the database management system; responding to the request by at least generating an internal table containing the data being transferred to the client; and transferring the data to the client by at least sending, to the client, one or more data chunks, each of the one or more data chunks including at least a portion of a column of data from the internal table, and each of the one or more data chunks including at least a portion of a dictionary and/or an index based at least on the request indicating that the data transferred to the client is to be compressed.

12 . The method of claim 11 , wherein at least some of the one or more data chunks include a value array comprising the column of data from the internal table based at least on the request indicating that the data transferred to the client is to be uncompressed.

13 . The method of claim 11 , further comprising:
compressing the column of data by at least generating a dictionary and an index, the dictionary enumerating one or more unique values appearing in the column of data, and the index identifying one or more rows occupied by each of the one or more unique values.

14 . The method of claim 13 , wherein the dictionary comprises a global dictionary enumerating every unique value that appear in the column of data.

15 . The method of claim 14 , wherein the one or more data chunks include a first data chunk and a second data chunk, wherein the first data chunk includes at least a portion of the global dictionary, and wherein the second data chunk includes at least a portion of the index.

16 . The method of claim 13 , wherein the dictionary comprises a first local dictionary and a second local dictionary, wherein the first local dictionary enumerates unique values appearing in a first data chunk from the one or more data chunks, and wherein the second local dictionary enumerates unique values appearing in a second data chunk from the one or more data chunks.

17 . The method of claim 16 , wherein the first data chunk includes the first local dictionary and a first index identifying rows occupied by the unique values enumerated in the first local dictionary, and wherein the second data chunk includes the second local dictionary and a second index identifying rows occupied by the unique values enumerated in the second local dictionary.

18 . The method of claim 11 , wherein a first data chunk and a second data chunk from the one or more data chunks include data from a first column of data in the internal table, wherein a third data chunk from the one or more data chunks includes data from a second column of data in the internal table, and wherein the third data chunk is sent to the client prior to the second data chunk in order to enable a formation of a complete row of data from the internal table.

19 . The method of claim 11 , wherein a data chunk is sent to the client upon determining that the data chunk is full.

20 . A non-transitory computer readable medium storing instructions, which when executed by at least one data processor, result in operations comprising:
receiving, at a database management system, a request to transfer, to a client, data stored at a database coupled with the database management system; responding to the request by at least generating an internal table containing the data being transferred to the client; and transferring the data to the client by at least sending, to the client, one or more data chunks, each of the one or more data chunks including at least a portion of a column of data from the internal table, and each of the one or more data chunks including at least a portion of a dictionary and/or an index based at least on the request indicating that the data transferred to the client is to be compressed.

Assignees

• Sap Se

Inventors

• Welch Timothy
• Ushakov Andrew
• Cao Shuqing
• Kulkarni Ashutosh
• Avula Shyam Sunder Reddy
• Sabnis Ajit
• Ramakrishnan Meena

Classifications

• G06F16/252 Primary

  between a Database Management System and a front-end application · CPC title

• G06F16/245

  Query processing · CPC title

• G06F16/2282 Primary

  Tablespace storage structures; Management thereof · CPC title

• G06F17/30424

  Physics · mapped topic

• G06F17/30339 Primary

  Physics · mapped topic