On Wed, Jun 18, 2014 at 2:55 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Robert Haas <robertmh...@gmail.com> writes: >> On Tue, Jun 17, 2014 at 8:46 PM, Bruce Momjian <br...@momjian.us> wrote: >>> On Tue, Jun 17, 2014 at 07:12:16PM -0400, Tom Lane wrote: >>>> What about comparing to the symbolic value LOBLKSIZE? This would make >>>> pg_upgrade assume that the old installation had been tweaked the same >>>> as in its own build. This ends up being the same as what you said, >>>> ie, effectively no comparison ... but it might be less complicated to >>>> code/understand. > >>> OK, assume the compiled-in default is the value for an old cluster that >>> has no value --- yeah, I could do that. > >> I'm not really sure why this is better than Bruce's original proposal, >> though. > > The net behavior would be the same, but I thought it might be easier to > code by thinking of it this way. Or maybe it wouldn't --- it's just a > suggestion.
Well, the difference is that if we just don't check it, there can never be an error. Basically, it's the user's job to DTRT. If we check it against some semi-arbitrary value, we'll catch the case where the old cluster was modified with a custom setting and the new one was not - but couldn't we also get false positives under obscure circumstances? -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
