Kbase P113894: What types of events change SQL statistics the most?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
1/5/2011 |
|
Status: Verified
GOAL:
What types of events change SQL statistics the most?
GOAL:
Do schema updates change SQL statistics?
GOAL:
Does a dump and load change SQL statistics?
GOAL:
Do mass updates change SQL statistics?
FACT(s) (Environment):
All Supported Operating Systems
Progress 9.x
OpenEdge 10.x
FIX:
Schema updates, by themselves, do not distort statistics. If new tables are defined and loaded with data, then it is recommended to do Update Statistics for those tables. In this case, SQL statistics are not automatically updated or created. Someone has to execute the UPDATE STATISTICS command.Dump and load, say for a table reorganization, does not affect statistics.
The most basic guideline is that changes in database data that change the relative proportions of tables and indexes are significant. Such changes are a good reason to get new statistics. For instance, if 2 tables T1 and T2 eachgrow at 5% a month then the old statistics would be fine. If T1 grows 2% and T2 grows 25% then get new statistics.
For mass updates and conversion type activities (for example actions that write thousands to tens of thousands of records in one fell swoop), it all depends on the percentages. If a table has 1 million rows, and 10K rows are added, it is not a big change. However, if a table has 50K rows, and 10K are added, then get new statistics.