Hello,
A few days ago I was surprised a CREATE TABLE containing FK constraint
was stuck due to an automatic vacuum freeze (which took
ShareUpdateExclusiveLock if I remember) on referenced table.
After digging into the code I found theses lines in tablecmds.c :
/*
* Grab ShareRowExclusiveLock on the pk table, so that someone doesn't
* delete rows out from under us.
*/
Maybe it should be documented in theses pages?
https://www.postgresql.org/docs/current/static/sql-createtable.html
https://www.postgresql.org/docs/current/static/sql-altertable.html
If you agree I can send a patch.
Regards,
