Hi

Does any one know in Oracle 9.2 when histograms are involved how is density

calculated? Without histograms is 1/NDV but I cant find a suitable way to

find the density when there are histograms.

This question is because I have a 10053 trace file with this:

SINGLE TABLE ACCESS PATH

Column: COD_C Col#: 2 Table: EMP_CL Alias: CL

NDV: 3 NULLS: 0 DENS: 4.0526e-09

FREQUENCY HISTOGRAM: #BKT: 37012907 #VAL: 3

Column: COD_A Col#: 3 Table: EMP_CL Alias: CL

NDV: 2 NULLS: 0 DENS: 4.0526e-09

FREQUENCY HISTOGRAM: #BKT: 37012907 #VAL: 2

TABLE: EMP_CL ORIG CDN: 123376357 ROUNDED CDN: 442543 CMPTD CDN:

442543

Access path: tsc Resc: 35875 Resp: 35875

BEST_CST: 35875.00 PATH: 2 Degree: 1

The query should returns around 3 million rows but I dont understand how the

computed cardinality is 442543? I suspect it calculates that using density

which shows 4.0526e-09

!

Thanks