From e6056363889a00699fcb6ef6ef8ce9bc3e007d7e Mon Sep 17 00:00:00 2001
From: "Andrey V. Lepikhov" <a.lepikhov@postgrespro.ru>
Date: Thu, 6 Dec 2018 11:09:17 +0500
Subject: [PATCH] Print All dependencies on error

---
 src/backend/catalog/dependency.c | 59 ++++++++++++++++++++++++++++----
 1 file changed, 52 insertions(+), 7 deletions(-)

diff --git a/src/backend/catalog/dependency.c b/src/backend/catalog/dependency.c
index 7dfa3278a5..e84143af2a 100644
--- a/src/backend/catalog/dependency.c
+++ b/src/backend/catalog/dependency.c
@@ -595,7 +595,9 @@ findDependentObjects(const ObjectAddress *object,
 				 */
 				if (stack == NULL)
 				{
-					char	   *otherObjDesc;
+					char		*emsg = NULL;
+					int			emsgbufsize = 1024;
+					char		*depObjDesc;
 
 					if (pendingObjects &&
 						object_address_present(&otherObject, pendingObjects))
@@ -605,14 +607,57 @@ findDependentObjects(const ObjectAddress *object,
 						ReleaseDeletionLock(object);
 						return;
 					}
-					otherObjDesc = getObjectDescription(&otherObject);
+
+					do
+					{
+						ObjectAddress depObject;
+						Form_pg_depend foundDep = (Form_pg_depend) GETSTRUCT(tup);
+
+						depObject.classId = foundDep->refclassid;
+						depObject.objectId = foundDep->refobjid;
+						depObject.objectSubId = foundDep->refobjsubid;
+
+						if (object_address_present(&depObject, pendingObjects))
+							continue;
+
+						if ((foundDep->deptype == DEPENDENCY_EXTENSION) &&
+							((flags & PERFORM_DELETION_SKIP_EXTENSIONS) ||
+							 (creating_extension &&
+							  depObject.classId == ExtensionRelationId &&
+							  depObject.objectId == CurrentExtensionObject))
+						   )
+							continue;
+
+						if ((foundDep->deptype != DEPENDENCY_INTERNAL) &&
+							(foundDep->deptype != DEPENDENCY_INTERNAL_AUTO)
+							)
+							continue;
+
+						depObjDesc = getObjectDescription(&depObject);
+						if (emsg == NULL)
+							emsg = palloc0(emsgbufsize);
+						else
+							strcat(emsg, " or ");
+
+						if (strlen(depObjDesc) > emsgbufsize - strlen(emsg))
+						{
+							char	*tmpstr;
+
+							emsgbufsize += strlen(depObjDesc) + 4;
+							tmpstr = palloc0(emsgbufsize);
+							memcpy(tmpstr, emsg, strlen(emsg));
+							pfree(emsg);
+							emsg = tmpstr;
+						}
+						strcat(emsg, depObjDesc);
+					} while (HeapTupleIsValid(tup = systable_getnext(scan)));
+
 					ereport(ERROR,
 							(errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
-							 errmsg("cannot drop %s because %s requires it",
-									getObjectDescription(object),
-									otherObjDesc),
-							 errhint("You can drop %s instead.",
-									 otherObjDesc)));
+							 errmsg("cannot drop %s because another object requires it",
+									getObjectDescription(object)),
+							 errhint("You can try to drop one of the following: %s.",
+									 emsg)));
 				}
 
 				/*
-- 
2.17.1