Re: snapshot too old with exp direct=y

In article <3974ab13.79745553_at_news.earthlink.net>,   andreyNSPAM_at_bookexchange.net (NetComrade) wrote:
> I used to get this error when I had 'consistent=y', and it was pretty
> clear why the error was happenning, but with direct=y and export file
> being created not being 'consistent' I don't understand why it would
> still need to read the rollback segment.
>
> . . exporting table ROSTER_CACHE_DATE
> 1 rows
> exported
> EXP-00008: ORACLE error 1555 encountered
> ORA-01555: snapshot too old: rollback segment number 6 with name
> "BIG_RBS" too s
> mall
> EXP-00000: Export terminated unsuccessfully
> Sun Jul 16 02:15:25 CDT 2000
>
> Thanx
> ---------------
> In case I forgot to mention:
> We use Oracle 7.3.4 and 8.1.6 on Solaris 2.6, 2.7 boxes
> ---------------
> Andrey Dmitriev eFax: (978) 383-5892 Daytime: (917) 750-3630
> AOL: NetComrade ICQ: 11340726 remove NSPAM to email
>

for the same reason.

when you use consistent=y -- every table is exported as it looked when the EXP began.

when you don't, each and every TABLE is exported consistently. You must be exporting a largish table and you have active transactions against it and before you can finish reading it -- the rollback needed to reconstruct some block at the "end of the table" has been overwritten.

The only way to avoid that particular situation is to allocate additional sufficient *permanent* rollback segment space (eg: set minextents higher).

direct=y stills reads the data via SQL -- it just bypasses some conversion layers in the server. It still employs statement level consistent reads.

--
Thomas Kyte (tkyte_at_us.oracle.com) Oracle Service Industries
Howtos and such: http://osi.oracle.com/~tkyte/index.html
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Opinions are mine and do not necessarily reflect those of Oracle Corp


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