Re: Strange snapshot too old during a select statement

From: Richard Foote <richard.foote_at_bigpond.com>
Date: Thu, 11 Mar 2004 20:08:55 +1000
Message-ID: <040901c40750$dccbac10$0100000a@FOOTE>

Strange snapshot too old during a select statementHi Philippe,

Ummm, I must be missing something here ?

Snapshot too old errors occur because Oracle can't reconstruct a consistent image of a block for the purposes of a consistent read.

And when do you generally require a consistent read ? During a select ...

And when are you likely to hit a snapshot too old ? During a long running select as Oracle needs to reconstruct all blocks back to the time the query started and the likelihood of such being possible diminishes over time.

You've described the classic scenario when ORA-01555s occur.

I think the Oracle Support person who said it's not possible since this was only a select statement is smoking some seriously dangerous substances ;)

Cheers

Richard

Original Message ----- From: NGUYEN Philippe (Cetelem) To: 'oracle-l_at_freelists.org' Sent: Thursday, March 11, 2004 6:46 PM Subject: Strange snapshot too old during a select statement

Hi list!
we encounter a very strange "ORA-01555 : snapshot too old :rollback segment number 3 with name "_SYSSMU3$" too small" This is a very long query
With a query that only make a select statement. We have open a TAR with Oracle Support but they say that it's not possible since this only a "select" statement ?!! Any idea ?
TIA
Philippe

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Received on Thu Mar 11 2004 - 03:01:39 CST