MULTI-MASTER DATA REPLICATION IN A DISTRIBUTED MULTI-TENANT SYSTEM

• US 20160306837A1
• Filed: 06/30/2016
• Published: 10/20/2016
• Est. Priority Date: 04/11/2011
• Status: Active Grant

• Current Assignee: Salesforce.com, Inc.
• Original Assignee: Salesforce.com, Inc.
• Inventors: Varley, Ian, Hansma, Scott, Burstein, Paul
• Granted Patent: US 10,459,908 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/2322 using timestamps
• CPC Class Codes: G06F 16/2379 Updates performed during online database operations; commit processing
• CPC Class Codes: G06F 16/27 Replication, distribution or synchronisation of data between databases or within a distributed database system; Distributed database system architectures therefor
• CPC Class Codes: G06F 16/273 Asynchronous replication or reconciliation
• CPC Class Codes: G06F 16/275 Synchronous replication
• CPC Class Codes: G06F 16/93 Document management systems
• CPC Class Codes: G06F 16/9535 Search customisation based on user profiles and personalisation
• CPC Class Codes: G06F 16/954 Navigation, e.g. using categorised browsing

Abstract

A multi-master replication system is disclosed. The multi-master replication system allows a large set of peer instances to collaboratively replicate data to each other.

Claims

1. In a replicated database by an instance of the replicated database, wherein the instance is one of a plurality instances of the replicated database, and each instance is separately responsible for multiple database tables local to the respective instances, and wherein the plurality of instances of the replicated database comprise two or more data centers each data center having a leader instance and one or more non-leader instances, the one or more non-leader instances to communicate with other non-leader instances of the same data center and the leader instance of the same data center and not to instances of other data centers, the leader instance to communicate with leader instances of other data centers and not with non-leader instances of other data centers, a method comprising:

monitoring for a change to at least one record of the local database tables;

generating a chunk of information that stores metadata about record changes and corresponds to a discrete unit of progress for both change detection and transport; and

serving the chunk to another instance of the replicated database via one or more leader instances to replicate the detected change to the other instance.

2. The method of claim 1 further comprising:

receiving by the instance a chunk from a remote instance of the replicated database, which has metadata identifying a set of changed records for database tables of the remote instance;

in response to the receiving, requesting underlying data for changed records indicated in the received chunk via the one or more leader instances; and

upserting the changed records into the local database tables

3. The method of claim 2, wherein the instance includes a modification timestamp indicating a most recent update of the instance, and wherein requesting the underlying data further comprises:

updating the modification timestamp with a modification timestamp of the received chunk.

4. The method of claim 2, wherein receiving the chunk further comprises:

identifying a time-based trigger to update the instance; and

requesting chunks from one or more remote instances, wherein the instance requests underlying data and upserts changed records for each received chunk.

5. The method of claim 2, wherein upserting the changed records further comprises:

inserting new records into the local database tables for records that do not exist in the local database tables; and

merging changed data into the local database tables for records that do exist in the local database tables.

6. The method of claim 2, wherein upserting the changed records further comprises:

determining if a modification timestamp of a changed row of data is more recent than a corresponding row in the local database tables; and

merging changed data into the local database tables when the modification timestamp is more recent;

otherwise,

ignoring the changed data.