How to interpret endpoint_value for non-numeric columns?

I have a column with frequency histogram on varchar column and this puzzles me.

E.g. 4.4134523297546E35 has to be translated into a 1-2 character string somehow.

Regards ]]>

First you need to work out what you did to get these results – then you can explain how I could reproduce the example.

As it is you haven’t told me how you collected the statistics, or what the table looks like, or how it’s indexed, or what query you ran. Moreover, you haven’t given me any assurance that the pieces of the trace file are equivalent, so you may have omitted lines from the first sample that you’ve shown in the second.

As far as “strange” is concerned – I think it’s possible that you collected stats the first time in a way that got 100% sample and no histogram, and in the second case generated a histogram off a small sample – although I would have expected 5e-7 for the second density. However, I don’t see the “NewDensity” figures, so I’m not sure you haven’t been running with optimizer_features_enable set to a lower value.

]]>There is something strange with density with 11.2.0.2 ..

Table stats:

#Rows: 1000000 #Blks: 47414 AvgRowLen: 330.00 ChainCnt: 0.00

I have a column with only one distinct value.

AvgLen: 3 NDV: 1 Nulls: 0 Density: 1.000000

Now, after i’ve updated 1000 rows to null, the density dropped down .

AvgLen: 3 NDV: 1 Nulls: 1000 Density: 0.000001

Histogram: Freq #Bkts: 1 UncompBkts: 5452 EndPtVals: 1

any thoughts about this?

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