> On Jun 19, 2025, at 11:54 AM, Rui DeSousa <rui@crazybean.net> wrote: > > > >> On Jun 19, 2025, at 1:23 PM, Scott Ribe <scott_ribe@elevated-dev.com> wrote: >> >> I believe that if I UPDATE a row with the same values that it already has, this still dirties pages, writes the row, generates a WAL entry. There is no shortcut in the processing that's "hey, there's not really a change here, we'll just leave storage alone". >> >> Is this correct? >> > > Correct, but it can be avoided. > > No update occurs in this case:. > > update foo > set data = ‘hello world’ > where id = 33 > and data is distinct from ‘hello world’ > ;
That was my thought when I posted the original question, when I didn't know about suppress_redundant_updates_trigger. Now I'm thinking the trigger is an option.
- The trigger has the advantage that one doesn't have to maintain the WHERE clause--especially if the list of columns is long. - It has the disadvantage of always running, even in contexts where it might not be needed.
How much would fillfactor=50 (so as to enable HOT updates) mitigate the problem?
