help execution plan changes when using a dblink

Hi,

We face the strange problem that an executionplan is changed recently without
any reason. Now it runs with a full_table scan and it did not do so. The query is executed through a dblink and is part of a batch.

• nothing has been changed recently in the app everybody agrees on here,
• analyze runs each weekend and a select count(*) differs slightly between num_rows in dba_tables for the specific table
• when executing the query manually in two parts the subquery first and ten the value returned hardcoded in the main-query it performs very good
• when I ask for an explain plan in the database the link points to the explain plan says it uses an index

Details: oracle 7.3.4, hp-ux 10.20
Query:
select * from debtor_claims_at_deca_link
where debtor_claim_id =
(
select max(debtor_claim_id)
from debtor_claims_at_deca_link
where res_id = 17777291 and
counter_booking_flag = 'N'
)

Tia,

Jeroen

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Jeroen van Sluisdam
  INET: jeroen.van.sluisdam_at_vrijuit.nl

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