Re: Sequence numbers jumping

Fenella Tan wrote:
>
> We're having problems with our sequence numbers. For some reason, they
> seem to be jumping up by 20 instead of the specified increment by 1.
> Any ideas on what may cause this ? We're using Oracle 7.3 on UNIX with
> a Visual Basic front-end. The jumps happen intermittently. It'll work
> (increment by 1) for a few records, and then it'll suddenly go up by 20
> again. Appreciate any input.
>
> Fenella

See Oracle7 Server Application Developer's Guide: Managing Schema Objects (p. 2-18 in my edition):

"If the value of SEQUENCE_CACHE_ENTRIES [in the init.ora file] is too low, it is possible to skip sequence values"

Make sure that the value of this parameter exceeds the number of different sequences you use across all your applications.

You may recently have created more sequences and need to increase the value of this parameter. The default is 10 on my system.

(BTW, the above manual is the most massively useful source of helpful tuning advice that Oracle have ever produced, IMHO)

See also SQL Language Reference Manual:
Create Sequence: Caching Sequence Numbers "In the event of system failure (sic), all cached sequence values that have not been used in committed Data Manipulation Language statements are lost"

This is not likely to be a major source of lost values, I hope :-)

HTH

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