On Mon, Oct 23, 2017 at 01:27:43AM -0700, Andres Freund wrote: > On 2017-10-22 23:04:50 -0400, Tom Lane wrote: > > John Lumby <johnlu...@hotmail.com> writes: > > > I have a C function (a trigger function) which uses the PG_TRY() > > > construct to handle certain ERROR conditions. > > > One example is where invoked as INSTEAD OF INSERT into a view. It > > > PG_TRYs INSERT into the real base table, > > > but this table may not yet exist (it is a partitioned child of an > > > inheritance parent). > > > If the error is ERRCODE_UNDEFINED_TABLE, then the CATCH issues > > > FlushErrorState() and returns to caller who CREATes the table and > > > re-issues the insert. > > > All works perfectly (on every release of 9.x). > > > > If it works, it's only because you didn't try very hard to break it. > > In general you can't catch and ignore errors without a full-fledged > > subtransaction --- BeginInternalSubTransaction, then either > > ReleaseCurrentSubTransaction or RollbackAndReleaseCurrentSubTransaction, > > not just FlushErrorState. See e.g. plpgpsql's exec_stmt_block. > > > > There may well be specific scenarios where an error gets thrown without > > having done anything that requires transaction cleanup. But when you > > hit a scenario where that's not true, or when a scenario that used to > > not require cleanup now does, nobody is going to consider that a PG bug. > > It'd probably be a good idea to expand on this in the sgml docs. This > has confused quite anumber of people...
I know this is from 2017, but where would we document this? I don't see PG_TRY/PG_CATCH mentioned in the SGML docs at all. -- Bruce Momjian <br...@momjian.us> https://momjian.us EDB https://enterprisedb.com Only you can decide what is important to you.
