Re: Very slow metadata-only expdp
Date: Fri, 21 Oct 2016 02:29:40 -0500
Message-Id: <AFCFCC8A-22E0-42E7-BAD0-3C3E0B62DF8A_at_yahoo.com>
Hi Mladen,
There must be a confusion. The expdp is not for copying the whole DB, but only the metadata and that too, just for Constraints.
Deepak
> On Oct 21, 2016, at 1:14 AM, Mladen Gogala <gogala.mladen_at_gmail.com> wrote:
>
> Hi Deepak,
> With the database as big as 160TB, expdp is out of the question. I have looked into your arguments to the expdp command just now and noticed that you're exporting the entire DB, probably in order to put the DDL command into some kind of versioning system.
> Even RMAN backup is questionable. If you have 10 GB network over the company then two bonded 10GB interfaces can produce the maximum speed of around 7.5 TB/hour. In other words the only good method to backup such a monster are storage snapshots and then using SRDF, HUR (Hitachi) or SnapVault (NetApp) to deliver the snapshot to the safe location and possibly back it to LTO-7, which can store around 6 TB.
> Regards
>
>> On 10/21/2016 12:32 AM, Deepak Sharma wrote:
>> Thanks for your feedback.
>>
>> We currently have an Oracle SR, and they tried us to apply a few patches, but none of them have helped so far.
>> Is it possible for someone in this community to try an export similar to below and provide their findings? It probably needs to be at least a decent size large system for the issue to reproduce.
>>
>> For our tests, we've been using ~3TB DB and we see the slowness, but the real requirement is on a ~160TB prod DB.
>>
>> expdp userid=system/<passwd> DIRECTORY=DP_DIR LOGFILE=expdp_CONSTRAINT_ONLY.log DUMPFILE=expdp_CONSTRAINT_ONLY.dmp FULL=y METRICS=Y CONTENT=METADATA_ONLY INCLUDE=CONSTRAINT
>>
>>
>> -Thanks in advance
>>
>>
>>
>> On Thursday, October 20, 2016 11:12 PM, Mladen Gogala <gogala.mladen_at_gmail.com> wrote:
>>
>>
>> There are several bugs listed in the master note:
>>
>> https://blogs.oracle.com/db/entry/master_note_for_data_pump_doc_id_12647151
>>
>> Also, when you google for "oracle expdp slow", you will get a lot of hits, one of them from always helpful Mike Dietrich:
>> https://blogs.oracle.com/UPGRADE/entry/data_pump_imdp_over_network
>>
>> It is worth researching some of those hits, since they come from some very good people. Also, the problem may be in using wrong plans when accessing SYS tables. When exporting metadata only, you are only accessing SYS tables. Try running data dictionary statistics and gather system statistics. That may help.
>>
>> Regards
>>
>>
>>
>>
>> On 10/19/2016 04:12 PM, Deepak Sharma (Redacted sender sharmakdeep_oracle for DMARC) wrote:
>>> I guess I should rephrase the real issue wrt the export of metadata. >>> expdp userid=system/<passwd> DIRECTORY=DP_DIR LOGFILE=expdp_CONSTRAINT_ONLY.log DUMPFILE=expdp_CONSTRAINT_ONLY.dmp FULL=y METRICS=Y CONTENT=METADATA_ONLY INCLUDE=CONSTRAINT
>>
>> --
>> Mladen Gogala
>> Oracle DBA
>> Tel: (347) 321-1217
>>
>>
> > > -- > Mladen Gogala > Oracle DBA > Tel: (347) 321-1217
-- http://www.freelists.org/webpage/oracle-lReceived on Fri Oct 21 2016 - 09:29:40 CEST