Date: Sun, 17 Sep 2006 12:22:33 +0200
From: Adriaan van Os <postgres@microbizz.nl>
Subject: Re: Progress of asynchronous queries
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Jeroen T. Vermeulen wrote:
> Adriaan van Os wrote:
> 
>> Besides, when more than one user is connected, multiple SQL commands may
>> behave different than a
>> single SQL command
>> (<http://www.postgresql.org/docs/8.1/static/transaction-iso.html>)
> 
> But you'd be doing this in a transaction anyway: you can't declare a
> cursor without starting a transaction first.Yes, you could deliberately
> declare "WITH HOLD" and keep using your cursor after commiting or aborting
> the transaction.  But even then, so far as I know, the cursor presents a
> snapshot view of its result set so you get an effective isolation level of
> "serializable" even then.

No, carefully read <http://www.postgresql.org/docs/8.1/static/transaction-iso.html>.

> The number of users has nothing to do with the matter

It does.

> if that were a real
> concern, you'd be using a serializable transaction anyway, so you wouldn't
> have to worry about it even if cursors did behave as "read committed."

I don't want to be forced to use serializable transaction mode, just because I want to know the 
progress of an SQL command.

Regards,

Adriaan van Os