Torsten Förtsch wrote: > if I do something like this: > > BEGIN; > UPDATE tbl SET data='something' WHERE pkey='selector'; > UPDATE tbl SET data=NULL WHERE pkey='selector'; > COMMIT; > > Given 'selector' actually exists, I get a separate WAL entry for each of the updates. My question is, > does the first update actually hit the data file? It should, yes. > If I am only interested in the first update hitting the WAL, does it make sense to do something like > the above in a transaction? Would that help to keep the table small in a high concurrency situation? > The table itself has a small fillfactor. So, in most cases there should be enough space to do a HOT > update. For that HOT update, is that second update setting data to NULL beneficial or rather adverse? How could the second update *not* be WAL logged? Maybe you could explain what you are trying to achieve. Yours, Laurenz Albe -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
