Thanks much Tim. You answered everything.
Sincerely - Woody
On Wed, Aug 12, 2015 at 12:51 PM, Tim Gorman <tim@xxxxxxxxx> wrote:
Woody,
Right and right, respectively.
On the latter point, please note that the FLASHBACK_SCN value always
specifies a SCN value on the source database, whether you're using "impdp"
or "expdp". So with "expdp", the use of FLASHBACK_SCN is pretty
straightforward, because you're exporting from the source database. But
with "impdp" the FLASHBACK_SCN parameter must be used in conjunction with
the NETWORK_LINK parameter to copy the data over to the destination
database from the remote source database, so the SCN value still pertains
only to the source database.
Hope this helps...
Thanks!
-Tim
On 8/12/15 10:30, Woody McKay wrote:
Thanks Tim. That helps a lot.
Lastly:
On imports, ora_rowscn on table data will get scn's from the DB scn and
not what was exported? Right?
The only use of the scn in a datapump file would be used for
flashback_scn? Right?
On Wed, Aug 12, 2015 at 12:19 PM, Tim Gorman <tim@xxxxxxxxx> wrote:
Woody,
The Oracle SCN is a six-byte integer implemented in two parts: a 4-byte
lower-order number and a 2-byte "wrap" counter. As SCN value increases, it
increments the 4-byte portion, and when that hits the 32-bit maximum value,
it "wraps" back to zero and the 2-byte counter is incremented.
With 48 bits, the maximum SCN value is 281,474,976,710,656 (i.e. 281
trillion).
For reference, this allows 16,384 increments per second for about 544.7
years.
There is no Y2K issue pending for Oracle anytime soon, but the next
generation will probably need to deal with it.
Some years ago, there was a bug involving database links which caused the
SCN to increase very rapidly, bringing the 500 year estimate within our
lifetime, but that's been resolved, I believe.
Hope this helps...
-Tim
On 8/12/15 9:35, Woody McKay wrote:
Hi all,
I was reading an AskTom article and it talked about the SCN wrapping at
some point. If this is so, then how large can the SCN grow to before it
wraps? Where is the wrap count stored?
On imports, ora_rowscn on table data will get scn's from the DB scn and
not what was exported?
The only use of the scn in a datapump file would be used for
flashback_scn? Right?
Thanks for all answers.
--
Sincerely,
WoodyMcKay
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--
Sincerely,
WoodyMcKay
