It appears to me you might be making this a lot more difficult than necessary. Why not just pre-create the required partitions daily or weekly or monthly? Or do you have a requirement that a new partition only be created the first time it is required?
On Thu, May 18, 2017 at 3:31 PM, David G. Johnston < david.g.johns...@gmail.com> wrote: > On Thu, May 18, 2017 at 1:18 PM, Rob Brucks <rob.bru...@rackspace.com> > wrote: > >> According to this post, adding "if not exists" won't really help for race >> conditions. >> >> >> >> "The bottom line is that CREATE TABLE IF NOT EXISTS doesn't pretend to >> >> handle concurrency issues any better than regular old CREATE TABLE, >> >> which is to say not very well." - Robert Haas >> >> >> >> https://www.postgresql.org/message-id/CA+TgmoZAdYVtwBfp1FL2s >> mzbihcwt4uprzrlnnx1nb30ku3...@mail.gmail.com >> >> >> >> It still doesn't explain how the function got past creating the table, >> but failed on the index. If another thread was also creating the table >> then there should have been lock contention on the create table statement. >> >> >> > AT1: Insert, failed, cannot find table > AT2: Insert, failed, cannot find table > BT2: Create Table, succeeds > BT1: Create Table; fails, it exists now, if exists converts to a warning > CT2: Create Index, succeeds > CT1: Create Index, fails , hard error > DT2: Insert, succeeds > DT1: Never Happens > > What that post seems to be describing is that it is possible the "BT1" > actually hard errors instead of just being converted into a notice. There > is no statement visible action to show that interleave but there is an > underlying race condition since both BT1 and BT2 are executing concurrently. > > In short even with IF NOT EXISTS you are not guaranteed to not fail. But > at least IF NOT EXISTS makes the probability of not failing > 0. It > doesn't handle the concurrency any better - but it does change the outcome > in some of those less-than-ideally handled situations. > > David J. > > -- Andrew W. Kerber 'If at first you dont succeed, dont take up skydiving.'
