Real Application Cluster:sequence failover

[kgb]

Hi All,

Could you tell me please how RAC handles sequences and what are restrictions? E.g. what will happen if one node fails. From logical point of view CURRVAL must return value from the failed node, but I can't find confirmation in the internet and if there are any conditions on it.

Thanks,

[pando]

those sequences are lost

[kgb]

Do you mean that after session will be reconnected to an alive node CURRVAL should return me this error:

ORA-08002: sequence SEQLOG.CURRVAL is not yet defined in this session

If it is so, is there any way to manage sequence failover with RAC ?

[davey23uk]

are you expecting a sequence to be a gapless number?

[kgb]

are you expecting a sequence to be a gapless number?

I am looking for the way to get a CURRVAL after a node failover

[davey23uk]

currval exists in a session, nothing else - so it cant be failed over as the sessions is gone

[PaxDBA]

RAC Preallocate a sequences range on the start up of each instance in the grid, then if there is a failure of a node the still to be used portion of numbers in the range are lost. It also means that sequences are not chronological sorted.