Another thing I’d be curious about- what does your expdp command look
like? Are you using DOP with it?
Kellyn
On Thu, Dec 16, 2021 at 6:57 AM Mark W. Farnham <mwf@xxxxxxxx> wrote:
I believe you raise another valid reason which might be common. Tim Gorman--
also mentioned small tables.
(I didn’t see that after my first export failed, since I made it a habit
that IF I needed an export I would arrange for quiescence and single row
scan the table before I exported it.)
I nearly always used “hot backup” for the whole database once we got to
6.0.36 and sqlplus COPY for individual things, but took special care
pre-emptively if an export was truly required.
IF you do only need part, a sqlplus COPY to the same machine was a neat
magic trick as far as network speed, giving you a nice clean thing to
export as long as you had the room.
Repeat after me: “More Disk”
mwf
*From:* Andrew Kerber [mailto:andrew.kerber@xxxxxxxxx]
*Sent:* Thursday, December 16, 2021 9:39 AM
*To:* Mark W. Farnham
*Cc:* Jack van Zanen; ORACLE-L
*Subject:* Re: expdp - cell single block physical read/ read request
Doesnt that mean its reading the undo tablespace for transaction
consistency?
On Thu, Dec 16, 2021 at 8:37 AM Mark W. Farnham <mwf@xxxxxxxx> wrote:
If memory serves this can happen with migrated rows, multi-block rows,
and/or multi-piece rows. Or at least some of those reasons.
Oracle is going to want the contents of your row to be contiguous in your
export file, so it needs all the pieces. I can’t remember what happens with
in-line and out of line binary object columns.
mwf
*From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto:
oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *Jack van Zanen
*Sent:* Wednesday, December 15, 2021 9:59 PM
*To:* oracle-l@xxxxxxxxxxxxx
*Subject:* expdp - cell single block physical read/ read request
Hi
Oracle 12.2.0.1 Exadata
I am running a datapump and two of the workers are spending a lot of time
on
- cell single block physical read
- cell single block read request
This does not make sense to me as it is full expdp I would expected a full
table scan type of wait, not single block
I checked mos but my search did not find anything related to my version
Does anyone know of any reason why this might happen?
Jack van Zanen
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