Re: Modifying TOAST thresholds
Zeugswetter Andreas DCP SD <zeugswettera@spardat.at>
From: "Zeugswetter Andreas ADI SD" <ZeugswetterA@spardat.at>
To: "Tom Lane" <tgl@sss.pgh.pa.us>, "Chris Browne" <cbbrowne@acm.org>, "Jan Wieck" <JanWieck@Yahoo.com>, <pgsql-hackers@postgresql.org>
Date: 2007-04-03T08:21:11Z
Lists: pgsql-hackers
> > ... should we revel > > in configurability, and allow CREATE TABLE/ALTER TABLE behavior to > > vary depending on the current threshold setting? We'd have to fix the > > toaster routines to not try to push stuff out-of-line when there is no > > out-of-line to push to ... but I think we probably had better do that > > anyway for robustness, if we're allowing any variability at all in > > these numbers. > > Actually, upon looking closely at the toast code, it already > does the right thing when there's no toast table. Good on > someone for getting that right. But we still need to think > about whether it's sane for CREATE/ALTER TABLE to condition > the create-a-toast-table decision on a parameter that may now > be changeable. I think it is ok to decide during creation with current settings. When a user wants a toast table that has not been created we can direct them to use some dummy "alter table ... set storage ..." and create a toast table if it does not exist (and the new settings opt for one). And a new threshold has immediate consequences for inline compression, so a change is not ignored. Andreas