diff --git a/contrib/babelfishpg_tsql/src/pl_handler.c b/contrib/babelfishpg_tsql/src/pl_handler.c
index a863232344..5f8f3757c7 100644
--- a/contrib/babelfishpg_tsql/src/pl_handler.c
+++ b/contrib/babelfishpg_tsql/src/pl_handler.c
@@ -149,7 +149,9 @@ extern bool pltsql_check_guc_plan(CachedPlanSource *plansource);
 bool		pltsql_function_as_checker(const char *lang, List *as, char **prosrc_str_p, char **probin_str_p);
 extern void pltsql_function_probin_writer(CreateFunctionStmt *stmt, Oid languageOid, char **probin_str_p);
 extern void pltsql_function_probin_reader(ParseState *pstate, List *fargs, Oid *actual_arg_types, Oid *declared_arg_types, Oid funcid);
-static void check_nullable_identity_constraint(RangeVar *relation, ColumnDef *column);
+static void check_invalid_column_constraints(RangeVar *relation, ColumnDef *column);
+static void check_invalid_constraints(RangeVar *relation, Constraint *constraint);
+static bool checkAndSetTsqlSystemFunc(FuncCall *fc);
 static bool is_identity_constraint(ColumnDef *column);
 extern PLtsql_function *find_cached_batch(int handle);
 extern void apply_post_compile_actions(PLtsql_function *func, InlineCodeBlockArgs *args);
@@ -1089,7 +1091,7 @@ pltsql_post_parse_analyze(ParseState *pstate, Query *query, JumbleState *jstate)
 						switch (nodeTag(element))
 						{
 							case T_ColumnDef:
-								check_nullable_identity_constraint(stmt->relation,
+								check_invalid_column_constraints(stmt->relation,
 																   (ColumnDef *) element);
 								if (is_identity_constraint((ColumnDef *) element))
 								{
@@ -1176,7 +1178,7 @@ pltsql_post_parse_analyze(ParseState *pstate, Query *query, JumbleState *jstate)
 						switch (cmd->subtype)
 						{
 							case AT_AddColumn:
-								check_nullable_identity_constraint(atstmt->relation,
+								check_invalid_column_constraints(atstmt->relation,
 																   castNode(ColumnDef, cmd->def));
 								if (is_identity_constraint(castNode(ColumnDef, cmd->def)))
 								{
@@ -1204,6 +1206,8 @@ pltsql_post_parse_analyze(ParseState *pstate, Query *query, JumbleState *jstate)
 								{
 									Constraint *c = castNode(Constraint, cmd->def);
 
+									check_invalid_constraints(atstmt->relation, c);
+
 									if (rowversion_column_name)
 										validate_rowversion_table_constraint(c, rowversion_column_name);
 								}
@@ -1254,6 +1258,17 @@ pltsql_post_parse_analyze(ParseState *pstate, Query *query, JumbleState *jstate)
 								{
 									int			colnamelen = strlen(cmd->name);
 
+									if (nodeTag(cmd->def) == T_FuncCall)
+									{
+										if (atstmt->relation->relpersistence == RELPERSISTENCE_TEMP && 
+											!checkAndSetTsqlSystemFunc(castNode(FuncCall, cmd->def)))
+										{
+											ereport(ERROR,
+													(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+													errmsg("User-defined functions, partition functions, and column references are not allowed in expressions in this context.")));
+										}
+									}
+
 									/*
 									 * Disallow defaults on a rowversion
 									 * column.
@@ -1855,9 +1870,13 @@ revoke_type_permission_from_public(PlannedStmt *pstmt, const char *queryString,
 	CommandCounterIncrement();
 }
 
-
+/*
+ * Check for constraints that are invalid in TSQL. For example:
+ * 1. Identity columns cannot be nullable
+ * 2. User-defined functions (UDFs) are not allowed in TSQL temp table or table variable column defaults.
+ */
 static void
-check_nullable_identity_constraint(RangeVar *relation, ColumnDef *column)
+check_invalid_column_constraints(RangeVar *relation, ColumnDef *column)
 {
 	ListCell   *clist;
 	bool		is_null = false;
@@ -1866,6 +1885,7 @@ check_nullable_identity_constraint(RangeVar *relation, ColumnDef *column)
 	foreach(clist, column->constraints)
 	{
 		Constraint *constraint = lfirst_node(Constraint, clist);
+		check_invalid_constraints(relation, constraint);
 
 		switch (constraint->contype)
 		{
@@ -1890,6 +1910,76 @@ check_nullable_identity_constraint(RangeVar *relation, ColumnDef *column)
 						relation->relname)));
 }
 
+/*
+ * Similar to check_invalid_column_constraints, but for individual constraints, such as added by
+ * ALTER TABLE ADD CONSTRAINT
+ */
+static void
+check_invalid_constraints(RangeVar *relation, Constraint *constraint)
+{
+	switch (constraint->contype)
+	{		
+		case CONSTR_DEFAULT:
+		{
+			if (IsA(constraint->raw_expr, FuncCall))
+			{
+				FuncCall *fc = castNode(FuncCall, constraint->raw_expr);
+				if (relation->relpersistence == RELPERSISTENCE_TEMP && !checkAndSetTsqlSystemFunc(fc))
+				{
+					ereport(ERROR,
+							(errcode(ERRCODE_INVALID_COLUMN_DEFINITION),
+							errmsg("User-defined functions, partition functions, and column references are not allowed in expressions in this context.")));
+				}
+			}
+			break;
+		}
+
+		default:
+			break;
+	}
+}
+
+/*
+ * Returns true iff the function is a system function. For Babelfish, this means searching in the "sys"
+ * schema, but the "sys" schema is meant to be opaque to customers, so to match SQL Server behavior
+ * we assume that it will never be schema-qualified in order to be true.
+ * If we do find a matching system function, then we modify the func call to explicitly call the fully-qualified
+ * system function, to prevent inadvertently using any user-defined overrides for the function name.
+ */
+static bool
+checkAndSetTsqlSystemFunc(FuncCall *fc)
+{
+	List *name_to_search;
+	ObjectWithArgs *owa = makeNode(ObjectWithArgs);
+	char *sys = palloc0(4);
+	strncpy(sys, "sys", 3);
+	if (list_length(fc->funcname) == 1)
+	{
+		/* explicitly search in the "sys" schema */
+		name_to_search = list_make2(makeString(sys), linitial(fc->funcname));
+	}
+	else
+	{
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("Column \"%s\" is not allowed in this context, and the user-defined function or aggregate \"%s\" could not be found.",
+						strVal(linitial(fc->funcname)),
+						NameListToString(fc->funcname))));
+	}
+
+	owa->objname = name_to_search;
+	owa->args_unspecified = true;
+
+	if (LookupFuncWithArgs(OBJECT_FUNCTION, owa, true))
+	{
+		list_free(fc->funcname);
+		fc->funcname = name_to_search;
+		return true;
+	}
+
+	return false;
+}
+
 static void
 pltsql_sequence_validate_increment(int64 increment_by,
 								   int64 max_value,
diff --git a/test/JDBC/expected/temp_table.out b/test/JDBC/expected/temp_table.out
index 3a65d23ee7..7de7719c7a 100644
--- a/test/JDBC/expected/temp_table.out
+++ b/test/JDBC/expected/temp_table.out
@@ -1,3 +1,6 @@
+USE master
+GO
+
 -- BABEL-4912 test ALTER TABLE for temp tables
 CREATE TABLE #t1 (a INT IDENTITY PRIMARY KEY NOT NULL, b INT)
 GO
@@ -258,3 +261,210 @@ int
 
 DROP TABLE #t1
 GO
+
+-- BABEL-4868 disallow the usage of user-defined functions in temp table column defaults (to prevent orphaned catalog entries)
+CREATE FUNCTION temp_table_func1(@a INT) RETURNS INT AS BEGIN RETURN 1 END
+GO
+
+-- normal tables should be ok
+CREATE TABLE temp_table_t1(a INT DEFAULT temp_table_func1(5))
+GO
+
+INSERT INTO temp_table_t1 VALUES (DEFAULT)
+GO
+~~ROW COUNT: 1~~
+
+
+SELECT * FROM temp_table_t1
+GO
+~~START~~
+int
+1
+~~END~~
+
+
+DROP TABLE temp_table_t1
+GO
+
+-- temp tables should not work
+CREATE TABLE #t1 (a INT DEFAULT temp_table_func1(5))
+GO
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: User-defined functions, partition functions, and column references are not allowed in expressions in this context.)~~
+
+
+-- two and three part names should not work either
+CREATE TABLE #t1 (a INT DEFAULT dbo.temp_table_func1(6))
+GO
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: Column "master_dbo" is not allowed in this context, and the user-defined function or aggregate "master_dbo.temp_table_func1" could not be found.)~~
+
+
+CREATE TABLE #t1 (a INT DEFAULT master.dbo.temp_table_func1(7))
+GO
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: Column "master_dbo" is not allowed in this context, and the user-defined function or aggregate "master_dbo.temp_table_func1" could not be found.)~~
+
+
+-- also block adding columns via ALTER TABLE
+CREATE TABLE #t1 (a INT)
+GO
+
+ALTER TABLE #t1 ADD b INT DEFAULT temp_table_func1(5)
+GO
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: User-defined functions, partition functions, and column references are not allowed in expressions in this context.)~~
+
+
+DROP TABLE #t1
+GO
+
+-- same with table variables
+DECLARE @tv TABLE (a INT DEFAULT temp_table_func1(5))
+INSERT INTO @tv VALUES (DEFAULT)
+SELECT * FROM @tv
+GO
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: User-defined functions, partition functions, and column references are not allowed in expressions in this context.)~~
+
+
+-- system functions such as ISJSON() should work
+CREATE TABLE #t1 (a INT DEFAULT ISJSON('a'))
+GO
+
+ALTER TABLE #t1 ADD b INT DEFAULT ISJSON('b')
+GO
+
+INSERT INTO #t1 VALUES (DEFAULT, DEFAULT)
+GO
+~~ROW COUNT: 1~~
+
+
+SELECT * FROM #t1
+GO
+~~START~~
+int#!#int
+0#!#0
+~~END~~
+
+
+DROP TABLE #t1
+GO
+
+DECLARE @tv TABLE (a INT DEFAULT ISJSON('a'))
+INSERT INTO @tv VALUES (DEFAULT)
+SELECT * FROM @tv
+GO
+~~ROW COUNT: 1~~
+
+~~START~~
+int
+0
+~~END~~
+
+
+-- disallow "sys"-qualified function calls
+CREATE TABLE #t1 (a INT DEFAULT SYS.ISJSON('a'))
+GO
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: Column "sys" is not allowed in this context, and the user-defined function or aggregate "sys.isjson" could not be found.)~~
+
+
+-- disallow user-defined overrides for system functions
+CREATE FUNCTION ISJSON(@json TEXT) RETURNS INT AS BEGIN RETURN 10 END
+GO
+
+-- cannot use schema-qualified name
+CREATE TABLE #t1 (a INT DEFAULT dbo.ISJSON('a'))
+GO
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: Column "master_dbo" is not allowed in this context, and the user-defined function or aggregate "master_dbo.isjson" could not be found.)~~
+
+
+-- should work, default to using the system function
+CREATE TABLE #t1 (a INT DEFAULT ISJSON('a'))
+GO
+
+INSERT INTO #t1 VALUES (DEFAULT)
+GO
+~~ROW COUNT: 1~~
+
+
+SELECT * FROM #t1
+GO
+~~START~~
+int
+0
+~~END~~
+
+
+DROP TABLE #t1
+GO
+
+-- Aggregate functions should not work
+create table #t1(a int, b int default any_value(a))
+go
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: User-defined functions, partition functions, and column references are not allowed in expressions in this context.)~~
+
+
+create table #t1(a int, b int default any_value(1))
+go
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: User-defined functions, partition functions, and column references are not allowed in expressions in this context.)~~
+
+
+-- also validate that the restrictions work for ALTER TABLE ADD CONSTRAINT
+CREATE TABLE #t1 (a INT)
+GO
+
+-- user-defined functions should not work
+ALTER TABLE #t1 ADD CONSTRAINT myconstraint DEFAULT temp_table_func1(5) FOR a
+GO
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: User-defined functions, partition functions, and column references are not allowed in expressions in this context.)~~
+
+
+-- nor should system function overrides
+ALTER TABLE #t1 ADD CONSTRAINT myconstraint DEFAULT dbo.ISJSON('a') FOR a
+GO
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: Column "master_dbo" is not allowed in this context, and the user-defined function or aggregate "master_dbo.isjson" could not be found.)~~
+
+
+-- but system functions should still work
+ALTER TABLE #t1 ADD CONSTRAINT myconstraint DEFAULT ISJSON('a') FOR a
+GO
+
+INSERT INTO #t1 VALUES (DEFAULT)
+GO
+~~ROW COUNT: 1~~
+
+
+SELECT * FROM #t1
+GO
+~~START~~
+int
+0
+~~END~~
+
+
+DROP TABLE #t1
+GO
+
+DROP FUNCTION dbo.ISJSON
+GO
+
+DROP FUNCTION temp_table_func1
+GO
diff --git a/test/JDBC/input/temp_tables/temp_table.sql b/test/JDBC/input/temp_tables/temp_table.sql
index 697ab44617..203436a6ed 100644
--- a/test/JDBC/input/temp_tables/temp_table.sql
+++ b/test/JDBC/input/temp_tables/temp_table.sql
@@ -1,3 +1,6 @@
+USE master
+GO
+
 -- BABEL-4912 test ALTER TABLE for temp tables
 CREATE TABLE #t1 (a INT IDENTITY PRIMARY KEY NOT NULL, b INT)
 GO
@@ -163,3 +166,131 @@ GO
 
 DROP TABLE #t1
 GO
+
+-- BABEL-4868 disallow the usage of user-defined functions in temp table column defaults (to prevent orphaned catalog entries)
+CREATE FUNCTION temp_table_func1(@a INT) RETURNS INT AS BEGIN RETURN 1 END
+GO
+
+-- normal tables should be ok
+CREATE TABLE temp_table_t1(a INT DEFAULT temp_table_func1(5))
+GO
+
+INSERT INTO temp_table_t1 VALUES (DEFAULT)
+GO
+
+SELECT * FROM temp_table_t1
+GO
+
+DROP TABLE temp_table_t1
+GO
+
+-- temp tables should not work
+CREATE TABLE #t1 (a INT DEFAULT temp_table_func1(5))
+GO
+
+-- two and three part names should not work either
+CREATE TABLE #t1 (a INT DEFAULT dbo.temp_table_func1(6))
+GO
+
+CREATE TABLE #t1 (a INT DEFAULT master.dbo.temp_table_func1(7))
+GO
+
+-- also block adding columns via ALTER TABLE
+CREATE TABLE #t1 (a INT)
+GO
+
+ALTER TABLE #t1 ADD b INT DEFAULT temp_table_func1(5)
+GO
+
+DROP TABLE #t1
+GO
+
+-- same with table variables
+DECLARE @tv TABLE (a INT DEFAULT temp_table_func1(5))
+INSERT INTO @tv VALUES (DEFAULT)
+SELECT * FROM @tv
+GO
+
+-- system functions such as ISJSON() should work
+CREATE TABLE #t1 (a INT DEFAULT ISJSON('a'))
+GO
+
+ALTER TABLE #t1 ADD b INT DEFAULT ISJSON('b')
+GO
+
+INSERT INTO #t1 VALUES (DEFAULT, DEFAULT)
+GO
+
+SELECT * FROM #t1
+GO
+
+DROP TABLE #t1
+GO
+
+DECLARE @tv TABLE (a INT DEFAULT ISJSON('a'))
+INSERT INTO @tv VALUES (DEFAULT)
+SELECT * FROM @tv
+GO
+
+-- disallow "sys"-qualified function calls
+CREATE TABLE #t1 (a INT DEFAULT SYS.ISJSON('a'))
+GO
+
+-- disallow user-defined overrides for system functions
+CREATE FUNCTION ISJSON(@json TEXT) RETURNS INT AS BEGIN RETURN 10 END
+GO
+
+-- cannot use schema-qualified name
+CREATE TABLE #t1 (a INT DEFAULT dbo.ISJSON('a'))
+GO
+
+-- should work, default to using the system function
+CREATE TABLE #t1 (a INT DEFAULT ISJSON('a'))
+GO
+
+INSERT INTO #t1 VALUES (DEFAULT)
+GO
+
+SELECT * FROM #t1
+GO
+
+DROP TABLE #t1
+GO
+
+-- Aggregate functions should not work
+create table #t1(a int, b int default any_value(a))
+go
+
+create table #t1(a int, b int default any_value(1))
+go
+
+-- also validate that the restrictions work for ALTER TABLE ADD CONSTRAINT
+CREATE TABLE #t1 (a INT)
+GO
+
+-- user-defined functions should not work
+ALTER TABLE #t1 ADD CONSTRAINT myconstraint DEFAULT temp_table_func1(5) FOR a
+GO
+
+-- nor should system function overrides
+ALTER TABLE #t1 ADD CONSTRAINT myconstraint DEFAULT dbo.ISJSON('a') FOR a
+GO
+
+-- but system functions should still work
+ALTER TABLE #t1 ADD CONSTRAINT myconstraint DEFAULT ISJSON('a') FOR a
+GO
+
+INSERT INTO #t1 VALUES (DEFAULT)
+GO
+
+SELECT * FROM #t1
+GO
+
+DROP TABLE #t1
+GO
+
+DROP FUNCTION dbo.ISJSON
+GO
+
+DROP FUNCTION temp_table_func1
+GO