Horton

Re: Patch: plan invalidation vs stored procedures

Hannu Krosing <hannu@2ndquadrant.com>

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From: Hannu Krosing <hannu@2ndQuadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Asko Oja <ascoja@gmail.com>, Pavel Stehule <pavel.stehule@gmail.com>, Dimitri Fontaine <dfontaine@hi-media.com>, pgsql-hackers@postgresql.org, Andrew Dunstan <andrew@dunslane.net>, David Fetter <david@fetter.org>, Martin Pihlak <martin.pihlak@gmail.com>
Date: 2008-08-19T10:38:10Z
Lists: pgsql-hackers 
On Mon, 2008-08-18 at 20:29 -0400, Tom Lane wrote:
> "Asko Oja" <ascoja@gmail.com> writes:
> > For users of stored procedures it is protection from downtime. For Skype it
> > has been around 20% of databse related downtime this year.
> 
> Perhaps Skype needs to rethink how they are modifying functions.

Why not suggest they just should stop using functions and move all
business logic into client or "3rd tier" ?

(Actually I would not recommend that  as functions are very good way to
abstract database access AND provide better security AND speed up
queries)

> The reason that this case wasn't covered in 8.3 is that there didn't
> seem to be a use-case that justified doing the extra work.  I still
> haven't seen one.  Other than inline-able SQL functions there is no
> reason to invalidate a stored plan based on the fact that some function
> it called changed contents.

Maybe there should be something in postgreSQL docs that warns users against 
using functions in any non-trivial circumstances, as functions are not 
expected to behave like the rest of postgreSQL features and there is 
not plan to fix that ?

----------------
Hannu