Manual sys catalog constraint setup to avoid downtime? - Mailing list pgsql-admin

From Jerry Sievers
Subject Manual sys catalog constraint setup to avoid downtime?
Date
Msg-id m3lkmnfdil.fsf@homie.jerrysievers.com
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Responses Re: Manual sys catalog constraint setup to avoid downtime?
List pgsql-admin
Admins; this is (I assume) a not uncommon scenario).

Suppose you are managing a BIG ugly DB that's in 24x7 production and
desperately in need of constraints of all types.

(Of course, you inherited this piece of crap and the irresponsible
designers are long gone :-)

You have verified that the application now honors the new constraints
because on your R&D DBs, the constraints are in place and no
constraint violations are occuring.

You can't however get business to sign off on proper constraint
addition via ALTER TABLE because the tables are huge and this locks
out concurrent activity for several hours.

My question;

Have any of you setup the constraints by doing manual catalog updates
and later (or maybe never),  gone back and cleaned up the
non-conforming data using small batch updates or deletes?

Frobing of pg_constraint and pg_depend (at least) would be required.

I'm wondering what non-obvious pitfalls exist here?

Comments?

--
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Jerry Sievers   305 854-3001 (home)     Production Database Administrator
                305 321-1144 (mobil    WWW E-Commerce Consultant

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