On Tue, Jul 18, 2017 at 07:26:30PM -0400, Tom Lane wrote: > > It's probably a bit late in the v10 cycle to be taking any risks in > > this area, but I'd vote for ripping out RememberToFreeTupleDescAtEOX > > as soon as the v11 cycle opens, unless someone can show an example > > of non-broken coding that requires it. (And if so, there ought to > > be a regression test incorporating that.)
I'm resending this in case it's been forgotten about and in case there's still time this cycle to follow through in removing RememberToFreeTupleDescAtEOX. ..And because I ran into it again earlier this month, ALTERing an 1600 column table with 500 children (actually while rewriting to reduce to 12 childs); on a dedicated DB VM with 8GB RAM: Mar 7 11:44:52 telsaDB kernel: Out of memory: Kill process 47490 (postmaster) score 644 or sacrifice child Mar 7 11:44:52 telsaDB kernel: Killed process 47490, UID 26, (postmaster) total-vm:6813528kB, anon-rss:5212288kB, file-rss:2296kB On Wed, Oct 18, 2017 at 02:54:54PM -0500, Justin Pryzby wrote: > Hi, > > I just ran into this again in another context (see original dicussion, quoted > below). > > Some time ago, while initially introducting non-default stats target, I set > our > non-filtering columns to "STATISTICS 10", lower than default, to minimize the > size of pg_statistic, which (at least at one point) I perceived to have become > bloated and causing issue (partially due to having an excessive number of > "daily" granularity partitions, a problem I've since mitigated). > > The large number of columns with non-default stats target was (I think) > causing > pg_dump --section=pre-data to take 10+ minutes, which makes pg_upgrade more > disruptive than necessary, so now I'm going back and fixing it. > > [pryzbyj@database ~]$ time sed '/SET STATISTICS 10;$/!d; s//SET STATISTICS > -1;/' /srv/cdrperfbackup/ts/2017-10-17/pg_dump-section\=pre-data |psql -1q ts > server closed the connection unexpectedly > This probably means the server terminated abnormally > before or while processing the request. > connection to server was lost > > [pryzbyj@database ~]$ dmesg |tail -n2 > Out of memory: Kill process 6725 (postmaster) score 550 or sacrifice child > Killed process 6725, UID 26, (postmaster) total-vm:13544792kB, > anon-rss:8977764kB, file-rss:8kB > > So I'm hoping to encourage someone to commit the change contemplated earlier.
