"Robert John Shepherd" <robert@reviewer.co.uk> writes:
> Whilst I often use views for convenience, is there any performance
> advantage at all in using a view rather than running the same query
> directly on the tables themselves?
No, a view is just a macro.
There is probably some minuscule cost difference involved --- you save
parsing and parse analysis of a long query string. On the other hand,
you pay to pull the view definition from the catalogs and merge it into
the given query. I'd not care to hazard a guess on whether the actual
net cost is more or less; but in any case these costs will be swamped
by query planning and execution, if the query is complex.
If you're concerned about reducing parse/plan overhead for repetitive
queries, the prepared-statement facility (new in 7.3) is what to look
at. Views won't do much for you.
regards, tom lane