I wrote:
> I propose that we handle this case by adding a new DEPFLAG_IS_SUBOBJECT
> flag to the column object's flags, denoting that we know the whole table
> will be dropped later. The only effect of this flag is to suppress
> reporting of the column object in reportDependentObjects.
Here's a proposed patch for that bit. As expected, it seems to eliminate
the variation in number-of-cascaded-drops-reported under
ignore_system_indexes. I do not see any regression outputs change
otherwise.
regards, tom lane
diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index 3529084..6b8c735 100644
*** a/src/backend/catalog/dependency.c
--- b/src/backend/catalog/dependency.c
*************** typedef struct
*** 102,107 ****
--- 102,108 ----
#define DEPFLAG_INTERNAL 0x0008 /* reached via internal dependency */
#define DEPFLAG_EXTENSION 0x0010 /* reached via extension dependency */
#define DEPFLAG_REVERSE 0x0020 /* reverse internal/extension link */
+ #define DEPFLAG_SUBOBJECT 0x0040 /* subobject of another deletable object */
/* expansible list of ObjectAddresses */
*************** reportDependentObjects(const ObjectAddre
*** 886,891 ****
--- 887,896 ----
if (extra->flags & DEPFLAG_ORIGINAL)
continue;
+ /* Also ignore sub-objects; we'll report the whole object elsewhere */
+ if (extra->flags & DEPFLAG_SUBOBJECT)
+ continue;
+
objDesc = getObjectDescription(obj);
/*
*************** object_address_present_add_flags(const O
*** 2320,2332 ****
* DROP COLUMN action even though we know we're gonna delete
* the table later.
*
* Because there could be other subobjects of this object in
* the array, this case means we always have to loop through
* the whole array; we cannot exit early on a match.
*/
ObjectAddressExtra *thisextra = addrs->extras + i;
! thisextra->flags |= flags;
}
}
}
--- 2325,2343 ----
* DROP COLUMN action even though we know we're gonna delete
* the table later.
*
+ * What we can do, though, is mark this as a subobject so that
+ * we don't report it separately, which is confusing because
+ * it's unpredictable whether it happens or not. But do so
+ * only if flags != 0 (flags == 0 is a read-only probe).
+ *
* Because there could be other subobjects of this object in
* the array, this case means we always have to loop through
* the whole array; we cannot exit early on a match.
*/
ObjectAddressExtra *thisextra = addrs->extras + i;
! if (flags)
! thisextra->flags |= (flags | DEPFLAG_SUBOBJECT);
}
}
}
*************** stack_address_present_add_flags(const Ob
*** 2374,2380 ****
* object_address_present_add_flags(), we should propagate
* flags for the whole object to each of its subobjects.
*/
! stackptr->flags |= flags;
}
}
}
--- 2385,2392 ----
* object_address_present_add_flags(), we should propagate
* flags for the whole object to each of its subobjects.
*/
! if (flags)
! stackptr->flags |= (flags | DEPFLAG_SUBOBJECT);
}
}
}
