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Message Posted: Wed, 18 Jul 2007 @ 15:07:33 GMT


     
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Subj:   AccessCount and LastAccessTimeStamp in Indices view
 
From:   CELIAMM

Hello all,

I don't know what values AccessCount and LastAccessTimeStamp have in Indices view. For example, I have a primary index in a table that is defined as:

     PRIMARY INDEX (COL1, COL2, COL3)

According to Indices view, primary index was access as follows:

     IndexType ColumnPosition ColumnName AccessCount LastAccessTimeStamp
     Q               1        COL1            321    2007-07-16 10:38:17
     Q               2        COL2              1    2007-07-16 11:44:51
     Q               3        COL3           NULL    NULL

What this 3 rows means? Was my primary index accessed 321 times, 322 times or only once? How are AccessCount and LastAccessTimeStamp stored to be seen in Indices view when index have more that one column? What values do they take for every column in the index?

Results I get for this primary index look as if index was accessed partially by COL1 321 times and it was accessed partially by COL2 only once in a different moment that COL1 was. However, I thought that primary index had to be used as a whole (all columns that make the primary index at the same time) to spread data into de AMPs when I try to retrieve data from the table, i.e. if I do:

     select *
     from MyTable

How primary index is used if I try to retrieve data as follows?:

     select *
     from MyTable,
     OtherTable
     where MyTable.COL1 = OtherTable.COL2

Thanks

Celia



     
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