Praveen Kumar N wrote:
>
> one more doubt.in the following example we dont need sort right.But in
> this case also relations were scanned sequentially one by one.
In this case it's because the result from one seqscan was materialized.
> So is it the
> case that any relation is accessed only once from database while executing
> a given query?
Not in general -- you'll see that behavior only in particular cases.
--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.
