Off to the races: Running Runstats by Howard Goldberg One of the most common maintenance activities performed on a Db2 LUW database is running Runstats on tables and indexes. Accurate database statistics are vital for the Db2 Optimizer to produce the most optimal plans. The optimizer...
2 Comments - no search term matches found in comments.
The DB2 for Linux, UNIX and Windows query optimizer is responsible for choosing optimal query access plans, however it can't do its job properly without vital information about your data and database objects. The RUNSTATS utility has been used for years by database administrators to collect...
The below SQL interprets the columns high2key & low2key of sysibm.syscolumns for decimal columns. Note the restrictions: coltype='DECIMAL' (since just designed for this case) and statstime (which should normally guarantee that low2key and high2key are filled). WITH a(t,c,n,l,s,v1,v2) AS ...
Selectivity Overrides – Fixing Your Filter Factor Problems By Joe Geller Scenario – your query is performing poorly. Checking an Explain, you see DB2 picked an access path which you think is less than optimal. First, you make sure there are appropriate indexes. Then you look to see...
Script enclosed to aid in reporting on runstats information for range-partitioned tables & their indexes and statistical views.
db2-script-for-runstats-on-range-partitioned-tables-indexes-and-materialized-views.txt
1 Comment - no search term matches found in comments.
This presentation reviews the basics of the RUNSTATS utility (What it does; Why you need to run it; How DB2 uses the information), and explores new statistics collected on data and indexes, including: partition level information on Data Partitioned Secondary Indexes; non-uniform distributon...
EU07B05.flv