Re: SCN why is it different
From: vit\.spinka <vit.spinka_at_vitspinka.cz>
Date: Tue, 19 Jan 2010 09:32:07 +0100
Message-Id: <KWHJPJ$6D9F1CDD72EB95D01E190C023AD43851_at_webmail2.forpsi.com>
The timestamp<->SCN conversions are not meant to be exact. The docs says:
Date: Tue, 19 Jan 2010 09:32:07 +0100
Message-Id: <KWHJPJ$6D9F1CDD72EB95D01E190C023AD43851_at_webmail2.forpsi.com>
The timestamp<->SCN conversions are not meant to be exact. The docs says:
> TIMESTAMP_TO_SCN takes as an argument a timestamp value and returns the >>approximate<< system change number (SCN) associated with that timestamp.
The precission was something like 5 seconds in 9i and vastly improved in 10g. But nevertheless, it's not tick-perfect. It's a tradeoff between precision and resources needed to attain it - and Oracle deems this to be the sweet point. And because it's main purpose is for flashback (all types) etc., it's probably good enough. If you want to be tick-perfect, just save directly the SCN (and it's much easier to get such precise SCN than such precise timestamp - from redo logs, ...).
Vit
-- http://www.freelists.org/webpage/oracle-lReceived on Tue Jan 19 2010 - 02:32:07 CST