Access Consistency in High-Availability Databases

Patent metadata

Field	Value
Publication number	US-2024411632-A1
Application number	US-202418779422-A
Country	US
Kind code	A1
Filing date	Jul 22, 2024
Priority date	Oct 21, 2020
Publication date	Dec 12, 2024
Grant date	—

Abstract

Techniques are disclosed relating to maintaining a high availability (HA) database. In some embodiments, a computer system receives, from a plurality of host computers, a plurality of requests to access data stored in a database implemented using a plurality of clusters. In some embodiments, the computer system responds to the plurality of requests by accessing data stored in an active cluster. The computer system may then determine, based on the responding, health information for ones of the plurality of clusters, wherein the health information is generated based on real-time traffic for the database. In some embodiments, the computer system determines, based on the health information, whether to switch from accessing the active cluster to accessing a backup cluster. In some embodiments, the computer system stores, in respective clusters of the database, a changeover decision generated based on the determining.

First claim

1 . (canceled)

2 . A non-transitory computer-readable medium having instructions stored thereon that are executable by an intermediary device to perform operations comprising:
determining, based on health information for one or more clusters of a database storing application data in a plurality of clusters, whether to switch from accessing an active cluster to accessing a backup cluster of the database; storing, in multiple clusters of the database, a changeover decision generated based on determining whether to switch from the active cluster to the backup cluster, wherein said storage of the changeover decision provides availability of the changeover decision when one or more clusters of the database are down; periodically receiving, from host computers included in a pool of host computers configured to respond to a plurality of requests to access the data stored in the database, updated health information, wherein the updated health information is generated based on changes in real-time traffic for the database; and updating, based on the updated health information, the changeover decision.

3 . The non-transitory computer-readable medium of claim 2 , wherein the application data is for communications initiated between applications of two or more computing devices prior to determining the health information, and wherein accessing the application data is based on:
receiving, from host computers in the pool of host computers, a plurality of requests to access the application data stored in the database; and responding, by accessing application data stored in the active cluster, to the plurality of requests.

4 . The non-transitory computer-readable medium of claim 2 , wherein the updated health information indicates whether one or more clusters in the database are healthy, and wherein the updated health information is received every second.

5 . The non-transitory computer-readable medium of claim 2 , wherein determining the health information includes determining whether one or more database accesses were successful, wherein the health information indicates inferior characteristics of the active cluster.

6 . The non-transitory computer-readable medium of claim 2 , wherein the health information is further generated by:
determining whether failure ratios for one or more clusters in the database, calculated based on health values for a plurality of requests for application data, satisfy a health threshold.

7 . The non-transitory computer-readable medium of claim 2 , wherein the stored changeover decision is accessible to host computers in the pool of host computers for determining whether to access the active cluster or the backup cluster included in the database based on receiving requests received from one or more client host computers requesting to access the database, wherein the stored changeover decision includes that specify for respective clusters in the database:
a name of a host computer in the pool of host computers; and a timestamp and a health vote.

8 . The non-transitory computer-readable medium of claim 2 , wherein the intermediary device is a distributed micro-service acting as a data access layer (DAL) for the database, wherein the intermediary device includes the pool of host computers, and wherein the pool of host computers maintain a plurality of connections to the database.

9 . A method, comprising:
determining, by a computer system based on state information for one or more clusters of a database storing data in a plurality of clusters, whether to switch from accessing an active cluster of the database to accessing a backup cluster; storing, by the computer system in multiple clusters of the database, a changeover decision generated based on determining whether to switch from the active cluster to the backup cluster; periodically receiving, by the computer system from host computers included in a pool of host computers configured to respond to a plurality of requests to access data stored in the database, updated state information; and updating, by the computer system based on the updated state information, the changeover decision.

10 . The method of claim 9 , further comprising:
removing, by the computer system from the state information, one or more state votes associated with one or more host computers that have been removed from the pool of host computers used in responding to the plurality of requests.

11 . The method of claim 9 , wherein the updated state information is received every minute.

12 . The method of claim 10 , wherein the database is a non-relational database, and wherein respective clusters in the database store copies of the same data.

13 . The method of claim 10 , wherein the changeover decision includes state votes that specify for respective clusters in the database:
a name of a host computer in the pool of host computers; and a timestamp and a cluster status.

14 . The method of claim 10 , wherein the computer system facilitates communication between a plurality of client host computers and the database.

15 . A system, comprising:
a processor; and a non-transitory computer-readable medium having stored thereon instructions that are executable by the processor to cause the system to perform operations comprising:
determining, based on status information for one or more clusters of a database storing data in a plurality of clusters, whether to switch from accessing an active cluster of the database to accessing a backup cluster;
storing, in multiple clusters of the database, a changeover decision generated based on determining whether to switch from the active cluster to the backup cluster, wherein the redundant storage of the changeover decision improves database downtimes;
periodically receiving, from host computers included in a pool of host computers configured to respond to requests to access the data stored in the database, updated status information; and
updating, based on the updated status information, the changeover decision.

16 . The system of claim 15 , wherein the instructions are executable by the processor to cause the system to further perform operations comprising:
removing, from the status information based on determining that one or more host computers in the pool of host computers are no longer active, information associated with the one or more host computers that are no longer active.

17 . The system of claim 16 , wherein the removing includes:
removing one or more status ballots associated with one or more host computers in the pool of host computers that are no longer active.

18 . The system of claim 15 , wherein the changeover decision includes status ballots that specify for respective clusters in the database:
a name of a host computer in the pool of host computers; and a timestamp and a health vote.

19 . The system of claim 15 , wherein the status information is generated by host computers in the pool of host computers by:
determining, based on success of one or more database accesses, status values for respective database accesses; and calculating, based on the status values, failure ratios for one or more clusters in the database, wherein calculating the failure ratios includes dividing a total number of timeout and failure status values by a total number of determined status values.

20 . The system of claim 19 , wherein the changeover decision is read by one or more host computers in the pool of host computers from the database based on executing a switch action thread.

Assignees

• Paypal Inc

Inventors

• Huang Zhe
• Mei Jia
• Li Xin
• Yue Ying
• Chen Chaoyi

Classifications

• G06F11/2082

  Data synchronisation · CPC title

• G06F11/2069

  Management of state, configuration or failover · CPC title

• G06F11/1469

  Backup restoration techniques · CPC title

• G06F11/3034

  where the computing system component is a storage system, e.g. DASD based or network based (digital input from or digital output to record carriers G06F3/06; digital recording or reproducing G11B20/18; for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS], H04L67/1097) · CPC title

• G06F11/1464

  for networked environments · CPC title