Index Why In the DB2 : Cost Calculation 2 : index only post I noticed something upsetting, well, at least it was upsetting to me. We looked at the explain plan for looking up 1 value by an index. The index had nlevel=3. So there is a root-node, some intermediate-nodes and finally finally some leaf-nodes. […]
Continue ReadingDB2 Cost : index of articles
I started a series of articles concerning the cost of queries (and as a consequence concerning the choices the optimizer makes). This post is a index of these articles. 1 – DB2 : Cost calculations 1 : Table Scan 2 – DB2 : Cost Calculations 2 : Index Only 3 – DB2 : Cost Calculations […]
Continue ReadingDB2 Explain plan doesn’t exists
Just a quick reminder: If you start a new database where you want to genrate some execution-plans you might run into the following : db2 => explain plan for select * from t1,t3 where t1.n1=t3.n1; DB21034E The command was processed as an SQL statement because it was not a valid Command Line Processor command. During […]
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