Multihost database host removal shortcut

Patent metadata

Field	Value
Publication number	US-12493602-B2
Application number	US-202217940904-A
Country	US
Kind code	B2
Filing date	Sep 8, 2022
Priority date	Sep 8, 2022
Publication date	Dec 9, 2025
Grant date	Dec 9, 2025

Abstract

The present disclosure provides more efficient techniques for removing a host from a multi-host database system. An instruction to remove a host system may be received. In response, a determination of whether the first host system does or does not store any source tables is made based on a host-type identifier for the host system. This determination may not require obtaining landscape information for each of the hosts in the database system. If the host system stores replica tables and does not store source tables, those replica tables may be dropped based on the determination that the first host system does not store any source tables. As such, in cases where table redistribution is not needed the landscape information is not obtained, thereby making the host removal process more efficient.

First claim

What is claimed is:

1 . A computer system, comprising:
one or more processors; one or more machine-readable medium coupled to the one or more processors and storing computer program code comprising sets instructions executable by the one or more processors to: receive a first instruction to remove a first host system of a plurality of host systems within a multi-host database system, the multi-host database system storing a plurality of source tables distributed across at least a portion of the plurality of host systems; determine, in response to the first instruction, that the first host system does not store any of the plurality of source tables based on a single host-type identifier for the first host system indicating that the first host system only stores replica tables and does not store source tables, the first host system storing one or more replica tables that are replicas of corresponding source tables from among the plurality of source tables; drop the one or more replica tables stored on the first host system, based on the determination that the first host system does not store any of the plurality of source tables, without obtaining a set of landscape information and without performing a table redistribution operation; and remove the first host system from the multi-host database system.

2 . The computer system of claim 1 , wherein the computer program code further comprises sets instructions executable by the one or more processors to:
determine that none of the one or more replica tables stored on the first host system were created based on a specific user-initiated request for a particular replica table to be created, the dropping of the one or more replicas tables stored on the first host system being performed based on the determination that the one or more replica tables were not created based on the specific user-initiated request.

3 . The computer system of claim 1 , wherein the landscape information includes table information identifying the plurality of source tables, partition information indicating how the plurality of source table are partitioned, and location information indicating which host systems store which source tables.

4 . The computer system of claim 1 , wherein the computer program code further comprises sets instructions executable by the one or more processors to:
access one or more table placement rules to obtain the host-type identifier of the first host system, wherein the table placement rules indicate a number and location of replicas of the plurality of tables among the plurality of host systems.

5 . The computer system of claim 4 , wherein the table placement rules indicate how the plurality of source tables are partitioned among the plurality of host systems.

6 . The computer system of claim 1 , wherein the computer program code further comprises sets instructions executable by the one or more processors to:
receive a second instruction to remove a second host system from the multi-host database system; determine, in response to the second instruction, that the second host system stores one or more source tables or that the second host system stores a second replica table created in response to a specific user-initiated request for the second replica table; obtain landscape information for each of the plurality of host systems in response to the determination that the second host system stores one or more source table or that the second host system stores the second replica table; and redistribute one or more of the one or more source tables and the second replica table to one or more other host systems of the plurality of host systems.

7 . The computer system of claim 1 , wherein the source tables corresponding to the one or more replica tables are stored at other hosts systems from among the plurality of host systems.

8 . One or more non-transitory computer-readable medium storing computer program code comprising sets of instructions to:
receive a first instruction to remove a first host system of a plurality of host systems within a multi-host database system, the multi-host database system storing a plurality of source tables distributed across at least a portion of the plurality of host systems; determine, in response to the first instruction, that the first host system does not store any of the plurality of source tables based on a single host-type identifier for the first host system indicating that the first host system only stores replica tables and does not store source tables, the first host system storing one or more replica tables that are replicas of corresponding source tables from among the plurality of source tables; drop the one or more replica tables stored on the first host system, based on the determination that the first host system does not store any of the plurality of source tables, without obtaining a set of landscape information and without performing a table redistribution operation; and remove the first host system from the multi-host database system.

9 . The non-transitory computer-readable medium of claim 8 , wherein the computer program code further comprises sets instructions to:
determine that none of the one or more replica tables stored on the first host system were created based on a specific user-initiated request for a particular replica table to be created, the dropping of the one or more replicas tables stored on the first host system being performed based on the determination that the one or more replica tables were not created based on the specific user-initiated request.

10 . The non-transitory computer-readable medium of claim 8 , wherein the landscape information includes table information identifying the plurality of source tables, partition information indicating how the plurality of source table are partitioned, and location information indicating which host systems store which source tables.

11 . The non-transitory computer-readable medium of claim 8 , wherein the computer program code further comprises sets instructions to:
access one or more table placement rules to obtain the host-type identifier of the first host system, wherein the table placement rules indicate a number and location of replicas of the plurality of tables among the plurality of host systems.

12 . The non-transitory computer-readable medium of claim 8 , wherein the table placement rules indicate how the plurality of source tables are partitioned among the plurality of host systems.

13 . The non-transitory computer-readable medium of claim 8 , wherein the computer program code further comprises sets instructions to:
receive a second instruction to remove a second host system from the multi-host database system; determine, in response to the second instruction, that the second host system stores one or more source tables or that the second host system stores a second replica table created in response to a specific user-initiated request for the second replica table; obtain landscape information for each of the plurality of host systems in response to the determination that the second host system stores one or more source table or that the second host system stores the second replica table; and redistribute one or more of the one or more source tables and the second replica table to one or more other host systems of the plurality of host systems.

14 . The non-transitory computer-readable medium of claim 8 , wherein the source tables corresponding to the one or more replica tables are stored at other hosts systems from among the plurality of host systems.

15 . A computer-implemented method, comprising:
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Assignees

• Sap Se

Inventors

• Leu Hans-Joerg
• Ding Dan
• Gajjalakonda Srinivas
• Qiu Fei
• Mueller Carsten
• Schroeder Alexander

Classifications

• G06F16/273

  Asynchronous replication or reconciliation · CPC title

• G06F16/278

  Data partitioning, e.g. horizontal or vertical partitioning · CPC title

• G06F16/2282 Primary

  Tablespace storage structures; Management thereof · CPC title

• G06F16/27 Primary

  Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor · CPC title