Kbase P5317: What are the rules for INDEX HINTS with Oracle DataServer?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
7/17/2009 |
|
Status: Verified
GOAL:
What are the rules for INDEX HINTS with Oracle DataServer?
GOAL:
How does Oracle data server generate index hints?
GOAL:
Rules for Index Hints
FACT(s) (Environment):
All Supported Operating Systems
Oracle DataServer
FIX:
The following are Progress rules for generating index hints to ORACLE.
1. If it's a join on the server, NO index hint.
2. If there is a use-index clause, it generates a hint.
3. If there is a BY clause (or implied ordering as in a FIND statement) and another index does NOT exist that would do a better job of selection in the WHERE clause, then an index hint is generated to help the ordering of the result set.
4. If the WHERE clause is ROWID = :value, a hint to retrieve by ROWID is given (also applies to DELETE and UPDATE).
5. If the WHERE clause is PROGRESS_RECID = :value, an index hint for
<table-name>##PROGRESS_RECID is issued.
Please note that these rules have been modified over time, and can change in the future. For instance, initially hints were only considered for tables with a PROGRESS_RECID column.