Re: [PATCH] Space reservation v02

Heikki Linnakangas wrote:
> Bruce Momjian wrote:
> > Heikki Linnakangas wrote:
> >>> For example CREATE/ALTER TABLE can cause problems.
> >> Yeah, if the pre-upgrade script determines the amount of reserved space 
> >> for each table, and sets it in pg_class or reloptions or whatever, it's 
> >> not clear how mwhat to do with tables created after the script is run. I 
> >> guess we need quick scan of pg_class before the actual upgrade to check 
> >> that you don't have newly-created tables, and refuse the upgrade if 
> >> there is.
> > 
> > This is where a pg_class column would be useful.  You default the column
> > value to -1.  The pre-upgrade script sets the proper reserved space, and
> > new tables get a -1 and you check for those just before the upgrade. 
> 
> You can do that with a flat file too. If there's any tables in the 
> database that were not present when pre-upgrade script was started, 
> throw an error.
> 
> It might be a bit simpler with a pg_class column, but if we don't know 
> what exactly we need to store there, and might need to resort to 
> different storage anyway, it doesn't seem worth it.
> 
> An extra table as Zdenek suggested in the passing might give the best of 
> both worlds. The pre-upgrade script can create it when it's run, so we 
> don't need to decide beforehand what columns we need, and it's a table 
> so you can query it etc.

Yep, makes sense.  I had forgotten that idea;  sorry.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
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