Re: Selects query inside function must read commited data

On Sun, 2004-01-25 at 08:51, V i s h a l Kashyap @ [Sai Hertz And
Control Systems] wrote:
> Since sai_func_a() which encapsulates the function sai_func_b has not
> completed yet till #4 or #5
> then how does the function sai_func_b reads the new data since it is
> not committed yet.
>
> If I am not wrong PostgreSQL select statements works on committed data
> thus the new
> inserted data at #3 must not be available to sai_func_b() till #5

No. All operations by a single transaction are visible inside the
transaction. Therefore an encapsulated function can see anything already
done in the whole transaction. A function must be entirely inside a
transaction and cannot start a transaction, so there can never be any
problem about this.

Within a transaction, you cannot see data committed by any _other_
transaction that had not already committed when your transaction
started.

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Oliver Elphick Oliver(dot)Elphick(at)lfix(dot)co(dot)uk
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