Kbase P5996: sql92 odbc performance is very slow
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
07/04/2003 |
|
Status: Unverified
FACT(s) (Environment):
Progress 9.1C
SYMPTOM(s):
ODBC 92 performance is very slow
SQL 92 performance is slow
CAUSE:
Due to a bug in our SQL Optimizer engine select statements with multiple joins in which the where clause did not have all the components specified to match an existing index might choose a poor index or possbily perform a full table scan.
The reasoning behind this problem is that in comparing two sets of joins,
the join with more actual components of an index would use that index even if there was a better index.
The Optimizer engine believes that any search of the database works better if there are more fields of an index to base the query on.
If one of the joins had 2 out of 4 fields of an index from that table and another join had 4 out 6 while working in the same table then the index with 4 of 6 fields would be handled first because it knows 66% accuracy for the 4 of 6 join whereas the 2 of 4 efficacy is only 50%.
FIX:
The fix is to get the most current patch for your Progress installation since this behavior is fixed in:
PATCH SUN SOLARIS INTEL 9.1C 9.1C08
PATCH Compaq Tru64 UNIX 9.1C 9.1C11
PATCH HP-UX 64-bit 9.1C 9.1C08
PATCH HP/UX 11 9.1C 9.1C09
PATCH IBM AIX 9.1C 9.1C10
PATCH LINUX Intel 9.1C 9.1C07
PATCH SUN SOLARIS 9.1C 9.1C11
PATCH SUN SOLARIS INTEL 9.1C 9.1C08
PATCH UNIX V.4 9.1C 9.1C09
PATCH WebSpeed Compaq Tru6 3.1C 3.1C11
PATCH WebSpeed HP-UX 64-bi 3.1C 3.1C08
PATCH WebSpeed HP/UX 11 3.1C 3.1C09
PATCH WebSpeed SUN SOLARIS 3.1C 3.1C11
PATCH WebSpeed UNIX V.4 3.1C 3.1C09
PATCH WebSpeed WIN NT 32 I 3.1C 3.1C15
PATCH WIN NT 32 Intel 9.1C 9.1C15
PATCH WIN NT Developer's W 9.1C 9.1C15
Remember patches should only be applied if you are have a specific need for it.