SQL Optimizer

Posted in 1997

Emil Sarkissian — 22 Mar 1997 09:48:20 -0500 — source: Informix-list mailing list archive (1991-1998)

Does anyone know what "Estimated Cost" really means, when the sqexplain.out file is generated by OnLine 5.1? When I add silly conditions like: SELECT ps.ln WHERE ps.sheet_date BETWEEN BeginDate AND EndDate AND ps.ln = ps.ln -- ??? cost goes down ??? the cost moves goes down... BTW Is there a comprehensive explanation of HOW the optimizer makes its decisions?