On Wed, Aug 1, 2018 at 9:48 PM, Andrey Lepikhov <a.lepik...@postgrespro.ru> wrote: > I use v3 version of the patch for a Retail Indextuple Deletion and from time > to time i catch regression test error (see attachment). > As i see in regression.diff, the problem is instability order of DROP ... > CASCADE deletions. > Most frequently i get error on a test called 'updatable views'. > I check nbtree invariants during all tests, but index relations is in > consistent state all time. > My hypothesis is: instability order of logical duplicates in index relations > on a pg_depend relation. > But 'updatable views' test not contains any sources of instability: > concurrent insertions, updates, vacuum and so on. This fact discourage me. > May be you have any ideas on this problem?
It's caused by an implicit dependency on the order of items in an index. See https://www.postgresql.org/message-id/20180504022601.fflymidf7eoencb2%40alvherre.pgsql. I've been making "\set VERBOSITY terse" changes like this whenever it happens in a new place. It seems to have finally stopped happening. Note that this is a preexisting issue; there are already places in the regression tests where we paper over the problem in a similar way. I notice that it tends to happen when the machine running the regression tests is heavily loaded. -- Peter Geoghegan