Re: pg_control is missing a field for LOBLKSIZE - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: pg_control is missing a field for LOBLKSIZE
Date
Msg-id 538F2C43.3040506@dunslane.net
Whole thread Raw
In response to pg_control is missing a field for LOBLKSIZE  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: pg_control is missing a field for LOBLKSIZE  (Andres Freund <andres@2ndquadrant.com>)
Re: pg_control is missing a field for LOBLKSIZE  (Stephen Frost <sfrost@snowman.net>)
List pgsql-hackers
On 06/04/2014 10:03 AM, Tom Lane wrote:
> I just chanced to notice that if someone were to change the value for
> LOBLKSIZE and recompile, there'd be nothing to stop him from starting
> that postmaster against an existing database, even though it would
> completely misinterpret and mangle any data in pg_largeobject.
>
> I think there ought to be a guard for that, for exactly the same reasons
> that we check TOAST_MAX_CHUNK_SIZE: correct interpretation of on-disk
> data requires that this value match the original database configuration.
>
> Obviously it's too late to do anything about this in existing branches,
> but I propose to add a field to pg_control after we branch off 9.4.
>
>             

If we did an initdb-requiring change for 9.4 could we piggy-back this 
onto it?


cheers

andrew



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