||Oracle Tips by Burleson
Oracle10g Grid Computing
Chapter 12 - RAC Design Considerations
Proper Sequence Usage
INSTANCE_NUMBER INTO INST_ID
EMP_ID_SEQ.NEXTVAL INTO SEQ_NUM
INST_SEQ_ID:=(INST_ID-1)*100000 + SEQ_NUM;
Figure 13.5: Example Staggered Sequence Trigger
Generally, sequences can be cached with cache values as high as 200 in
RAC. This is much higher than for a regular Oracle instance. If there
is insufficient caching, then contention can result which will show up
as an increase in service times. If there are performance problems due
to sequences, then examine the row cache locks
statistics in the v$system_eventview to determine whether the problem is due to the
use of Oracle sequences. This is discussed in the following points:
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