Postfix for #9166: A failed COMMIT of a transaction containing ALTER TABLE ... ADD leaves the RDB$FORMATS record of the next format number; clear vector of cached formats

Author: AlexPeshkoff

src/jrd/Database.h

@@ -130,6 +130,20 @@ class vec_base : protected pool_alloc<TYPE>
 
 	void operator delete(void* mem) { MemoryPool::globalFree(mem); }
 
+	// strip unused nulls in the end
+	void trimNulls()
+	{
+		auto* e = v.end();
+		for (; e != v.begin(); --e)
+		{
+			if (e[-1])
+				break;
+		}
+
+		if (e != v.end())
+			v.resize(e - v.begin());
+	}
+
 protected:
 	vec_base(MemoryPool& p, int len)
 		: v(p, len)

src/jrd/dfw.epp

@@ -5915,6 +5915,21 @@ static bool make_version(thread_db* tdbb, SSHORT phase, DeferredWork* work, jrd_
 				ERASE F;
 			}
 			END_FOR
+
+			relation = MET_lookup_relation(tdbb, work->dfw_name);
+			if (relation)
+			{
+				vec<Format*>* vector = relation->rel_formats;
+				if (arg->dfw_id < vector->count())
+				{
+					Format* format = (*vector)[arg->dfw_id];
+					(*vector)[arg->dfw_id] = NULL;
+
+					vector->trimNulls();
+
+					delete format;
+				}
+			}
 		}
 		break;