Re: how does expdp use undospace
- From: "David Fitzjarrell" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender "oratune@xxxxxxxxx" for DMARC)
- To: "mr.fishyu@xxxxxxxxx" <mr.fishyu@xxxxxxxxx>, "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 29 May 2014 07:35:22 -0700 (PDT)
It uses it the same way any query would use it when reconstructing the data
'image' at the time the query started. expdp creates a consistent 'image' of
the table data for each table exported; as such it's subject to the
availability of the redo/undo going back to the time the query/export started
for a given table. I blogged on that here:
The Dreaded ORA-01555
The Dreaded ORA-01555
After looking more closely at the blog I mentioned in my last entry I'm finding
more and more that this poor soul has offered in the way of advice that is
either incomplete or wrong. One of the mor...
View on dfitzjarrell.wordpress.com Preview by Yahoo
which explains the conditions causing the 'dreaded' ORA-01555, including
delayed block cleanout which may be affecting your exports.
David Fitzjarrell
Principal author, "Oracle Exadata Survival Guide"
On Thursday, May 29, 2014 8:20 AM, David Yu <mr.fishyu@xxxxxxxxx> wrote:
Hi List,
I am using expdp to dump two schemas in two sessions with parallel3,but I have
Ora-01555 error.
My understanding for the undo space usage by expdp is for the consistent read
for those blocks which are changed by the transactions after starting expdp.
I'd like to understand how dose expdp use the undo space?
Rgds
David--
//www.freelists.org/webpage/oracle-l
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