Your Data Guard environment has one physical standby database using Real-Time Query. Two sequences have been created by these SQL statements:
Neither sequence has been used since being created.
Session 1 connects to the primary database instance and issues these two SQL statements:
SELECT a.nextval FROM DUAL; SELECT b.nextval FROM DUAL;
Then session 2 connects to the physical standby database instance and issues the same SQL statements. Which output will be seen for session 2?
Then session 2 connects to the physical standby database instance and issues the same SQL statements. Which output will be seen for session 2?
A)
B)
C)
In Oracle, a sequence created with the GLOBAL keyword is available and can produce values across all sessions and instances. However, a sequence created with the SESSION keyword is only specific to the session it was created in. When the NEXTVAL is called for a sequence, it will increment according to the sequence's properties set during its creation.
Given the sequence creation statements and the actions performed:
The a sequence is global, which means it is available across the entire database, including the standby database with Real-Time Query enabled. So, when session 2 calls a.nextval, it will get the next value in the sequence, which is 21 since session 1 already retrieved 1.
The b sequence is session-specific, so when session 2 calls b.nextval, it will get the value 1 because for this new session on the standby, this is the first time the sequence is being accessed.
Therefore, the output for session 2 will be a output as 21 and b output as 1, which corresponds to Option C.
Arlie
10 months agoRyan
10 months agoTimothy
10 months agoArlie
11 months agoRyan
11 months agoTimothy
12 months agoStaci
12 months agoBenton
12 months agoDona
12 months agoLarae
1 years agoRessie
1 years agoDottie
1 years agoFreeman
11 months agoOllie
12 months agoRanee
12 months agoBulah
1 years agoSamira
1 years ago