Kbase P4969: How does the SQL-92 query optimizer work?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
15/10/2008 |
|
Status: Verified
GOAL:
How does the SQL-92 query optimizer work?
FIX:
The optimizer uses the information from UPDATE STATISTICS to make decisions about
the best query strategy to use when executing a particular SQL-92 statement.
Until a user, application, or SQL-92 script issues an UPDATE STATISTICS statement, the optimizer bases query strategies on values it derives from various defaults. These values might not lead to the best performance, so database administrators should issue an UPDATE STATISTICS operation periodically. See the "Progress SQL-92 Guide and Reference" for more details.
Additional details on the inner workings of the Progress SQL-92 query optimizer are included in the "Inside the SQL Query Optimizer" eSeminar. This eSeminar is produced by Progress Professional Services - Education and is available on CD media. Contact your Progress Sales Representative details.