Hi,

Does anyone know how to calculate the density for an index in SYBASE.

Regds,

R.R

Hi,

Does anyone know how to calculate the density for an index in SYBASE.

Regds,

R.R

>Hi,

> Does anyone know how to calculate the density for an index in SYBASE.

>Regds,

> R.R

calculate the density of your index by hand it is the:

"inverse of the number of unique values"

Take the number calculated above and multiply it by the number of rows in

your table..

20 unqiue values = 1/20 =.05 or 5% unique

15,000 rows in table

.05*15000=750 rows on average returned if that index is used.

Josef Richberg

Sybase Professional Services

So if you have 5 unique values you

1. FILLFACTOR (SCAN DENSITY VS. AVERAGE PAGE DENSITY)

Scenario:

Created a clustered index and nonclustered indexes on a

table with 5,953,675 rows using a fillfactor of "95" for

clustered index and "98" for nonclustered indexes.

After 82,119 inserts (.01 of table), the nonclustered

indexes had a value of "83" for scan density, "4" for

logical frag, and "96" for avg. page density. The

clustered index had a value of "96" for scan density, "1"

for logical frag, and "88" for avg. page density.

Methinks I should have used a fillfactor for the

nonclustered indexes a value of "96", and a fillfactor

value of "96" for the clustered index. The table and

indexes span multiple files. Confused on trade-off on

scan density versus avg. page density with nightly inserts.

Am in an OLAP (Data Warehouse) environment. Have other

tables with similiar scenarios (roughly one percent of

table being done nightly with inserts).

Am open to anything. Thank you

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