Which Primary Shards dependent on Which Standby Shards? – Oracle Sharding 12.2

Recently, I have received an email on my recent articles on Oracle Sharding. The question is very interesting even to me.  Consider I have created Primary Database with two shards[sh1, sh2] and also Standby Database with two shards[Sh3, Sh4] – Then Sh1 refers to Sh3 and vice versa Sh2 refers to Sh4? Below is the question from the reader.

http://www.ioug.org/blog/sharding-database-infrastructure-horizontally—sharding-in-oracle-12.2-part-1

http://select.ioug.org/blog/sharding-database-infrastructure-horizontally—sharding-in-oracle-12.2-part-2

If I remember correctly, I have not read that reference that Sh1 refers to only Sh3 and Sh2 refers only to Sh4. Hence to dig into this issue, I tried to review as much as information from GDS. GDSCTL does show the list of shards of the configuration and various things but there is no direct clue to explore the issue.

Finally, I have checked the Data Guard Broker and this utility cleared the doubt.  Sh1 configuration is a combination of Sh1 and Sh3 and Sh2 configuration is a combination of Sh2 and Sh4.

DGMGRL> show configuration
Configuration - sh1
Protection Mode: MaxPerformance
 Members:
 sh1 - Primary database
 sh3 - Physical standby database
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS (status updated 49 seconds ago)
DGMGRL>

DGMGRL> show configuration
Configuration - sh2
Protection Mode: MaxPerformance
 Members:
 sh2 - Primary database
 sh4 - Physical standby database
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS (status updated 15 seconds ago)
DGMGRL>

In fact, we can assume but it is limited to the only assumption. Hence, it is always to dig and explore for more clarification. 🙂