Re: Nested Sets

From: Christopher Browne <cbbrowne(at)acm(dot)org>
To: pgsql-sql(at)postgresql(dot)org
Subject: Re: Nested Sets
Date: 2005-04-16 21:34:28
Message-ID: m31x9a2yor.fsf@knuth.cbbrowne.com
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After takin a swig o' Arrakan spice grog, troels(at)arvin(dot)dk (Troels Arvin) belched out:
> On Sat, 16 Apr 2005 14:14:57 -0400, Andrew Sullivan wrote:
>> You shouldn't need to do anything special around table
>> locking.
>
> - Except of one wants "True Serializability" (see chapter 12.2 in the
> manual). But I don't know if it's possible to handle table locking from
> within a user defined function.

"Inside stored functions" is one of the ultimate examples of places
where you are certain to be honest-to-goodness inside a transaction.

You can't change transactions while inside a function; all the
in-the-function processing is sure to take place in one transaction's
context.

In theory, savepoints may ultimately change that a little bit, in that
you might have portions of processing in different subtransactions.

But nonetheless Andrew's point remains valid: There is no need to do
any special locking surrounding processing that goes on inside a
stored procedure because it is all suitably embedded in a transaction.
--
(reverse (concatenate 'string "moc.enworbbc" "@" "enworbbc"))
http://linuxdatabases.info/info/slony.html
"The problem with the current Lisp Machine system is that nothing ever
calls anything anymore." -- KMP

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