Baanboard.com

Go Back   Baanboard.com

User login

Frontpage Sponsor

Main

Google search


Poll
For ERP LN feature pack upgrade, what method of install are you using?
Installation Wizard into existing VRC
33%
Installation Wizard into new VRC
39%
Manual into existing VRC
6%
Manual into new VRC
22%
Total votes: 49

Baanboard at LinkedIn


Reference Content

 
Hints for a split query in level-2
By patvdv at 26 Feb 2008 - 21:57

Hints for a split query in level-2

To evaluate a query the Oracle level-2 driver may split up a query in several smaller ones (child queries). When this happens the hints of the main query are distributed over these smaller queries. This is done according to the same rules as when the query was truly distributed:

  1. An index hint is only added to a child query if it contains the corresponding table in its from clause.
  2. All other hints are added to all child queries.

Example

 select a.cuno, b.cuno
 from   tppdm740 a, tccom010 b
 where  a.cuno refers to b
 and    a._compnr = 812
 hint   use index 1 on b
 and    array fetching
 and    array size 100

The Oracle level-2 driver will split this query into the following to child queries:

Query 1:

 select a.cuno
 from   tppdm740 a
 and    array fetching
 and    array size 100

Query 2:

 select b.cuno
 from   tccom010 b
 where  b.cuno = <variable>
 hint   use index 1 on b
 and    array fetching
 and    array size 100

Query 1 does not have any execution plan hints and therefore the driver will generate default hints for this query. Just like with distributed queries you can prevent the driver from generating default hints for query 1 by adding the hint 'no hints' to the main query. Adding this hint will have no effect for query 2.

Related topics


0
No votes yet


All times are GMT +2. The time now is 02:44.


©2001-2018 - Baanboard.com - Baanforums.com