Re: Sequencing Problem in Transaction..

Bhuvan A wrote:
>
>
> On Feb 12, Christopher Kings-Lynne wrote:
>
> > Ummm...this is not a bug - it is utterly essential that sequences are not
> > rolled back!!!
> >
> > Think about this:
> >
> > Sequence counter is 9
> > Transaction 1 gets sequence no. 10
> > Transaction 2 gets sequence no. 11
> > transaction 1 rolls back, sequence no. reset to 9
> > Transaction 3 gets sequence number 10
> > Transaction 4 gets sequence number 11 - BAM!!!
> >
> Good and Thankx!!!

Believe it or not, this _wasn't_ in the FAQ, though it certainly is
asked enough times. Added now as item 4.15.4:

4.15.4) Why aren't my sequence numbers reused on transaction abort? Why are
there gaps in the numbering of my sequence/SERIAL column?

To improve concurrency, sequence values are given out to running
transactions as needed and are not locked until the transaction
completes. This causes gaps in numbering from aborted transactions.

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