Re: Why ORA-1555 snapshot too old.

I think you need to be a little more careful about how you describe this. The rollback segment does not get 'copies of database blocks' written into it, it get copies of the bits of rows that have been changed.

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Alex Filonov wrote in message
<336da121.0210230800.467dfcc4_at_posting.google.com>...


>The problem here is that rollback segment gets overwritten before

select


>statement finishes. This happens besause every transaction creates

undo copy of


>the database block. If you have many small transactions, you have

many undo


>copies of database blocks. You can also have many undo copies of the

same block.