Re: Accessing rows in large tables

Tsagarakis Manolis wrote:
> Assuming the worst case (1 million rows) we
> are looking for ways, to access rows fast. I've never worked with large
> tables in ORACLE, so I have the following questions:
>
> 1. Is it efficient to use indexes ?

Yes.

The only time an index is not feasible is when you are retrieveing more than 30%(?) of the rows in your query. In that case it is actually more effecient to read the rows directly and ignore the index.

> I read somewhere, that building indexes is efficient
> only for tables having number of rows in a particular range
> (eg. from 3000 to 300,000 rows).

No. The number of rows is not relevant.

Whether the index is used efficiently is the only test.

Use the largest Oracle block size available for your system.

Bruce...

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   T T T T T T T T        Bruce Pihlamae
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