Re: Tuning Over a DBLINK?

  • From: Juan Carlos Reyes Pacheco <jcdrpllist@xxxxxxxxx>
  • To: ORACLE-L <oracle-l@xxxxxxxxxxxxx>
  • Date: Tue, 21 Jan 2014 18:50:12 -0400

For remote queries I use two options
1) the hint /*+DRIVING_SITE(table)*/
 2) create a function table in the remote database, to get only the data I
want
3) I suppose I never tried, because I have standard one database, but a
materialized view could help too


2014/1/21 Uzzell, Stephan <SUzzell@xxxxxxxxxx>

>  Hi all,
>
>
>
> Hoping someone can point me in the right direction, or give me some basic
> reading material here…
>
>
>
> We have a query that (apparently) used to perform well, but recently runs
> 10+ minutes (long enough that the web-based front end times out). The
> problem, the reason I don’t know how to approach it, is that it is a query
> against a simple table joined to a view. And the view is a join of several
> tables from the other side of a db link.
>
>
>
> I don’t want to dump the whole plan here, but hopefully I’m not stripping
> out too much too relevant:
>
>
>
> |  12 |          NESTED LOOPS                |
> |     1 |   250 | 11948   (1)| 00:02:24 |        |      |
>
> |  13 |           REMOTE                     | GUEST_CHECK_LINE_ITEM_HIST
> |     4 |   748 | 11944   (1)| 00:02:24 |  MMHMS | R->S |
>
> |  14 |           TABLE ACCESS BY INDEX ROWID| MST_STORE_TAB
> |     1 |    63 |     1   (0)| 00:00:01 |        |      |
>
> |  15 |            INDEX UNIQUE SCAN         | MST_STORE_TAB_PK
> |     1 |       |     0   (0)|          |        |      |
>
>
>
> Unfortunately, I can’t tell from this what the access is for
> GUEST_CHECK_LINE_ITEM_HIST, and that is a significantly large partitioned
> table. Large enough that I’m sure it isn’t doing a FTS, or it would take a
> heck of a lot longer than this…
>
>
>
> How do I tune / investigate across a db link? Is there somewhere to see
> what is getting hidden under the operation “REMOTE”?
>
>
>
> Thanks!
>
>
>
> *Stephan Uzzell*
>
>
>

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