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

From Stephen Frost
Subject Re: pg_control is missing a field for LOBLKSIZE
Date
Msg-id 20140604143004.GA2556@tamriel.snowman.net
Whole thread Raw
In response to Re: pg_control is missing a field for LOBLKSIZE  (Andrew Dunstan <andrew@dunslane.net>)
Responses Re: pg_control is missing a field for LOBLKSIZE  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
* Andrew Dunstan (andrew@dunslane.net) wrote:
> 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?

I was thinking more-or-less the same thing...

Then again, I've never heard of a field complaint regarding this, so
pehraps it's not worth it.
Thanks,
    Stephen

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