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Disallow the use of user-defined functions in column defaults for tem…
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…p tables and table variables.

In SQL Server, it is prohibited for users to use user-defined functions as column defaults in temp tables and table variables - the only exception is in the tempdb database, but this is not currently even supported in Babelfish, so for now we will impose the same restrictions as exist elsewhere in SQL Server.

Task: BABEL-4868

Signed-off-by: Jason Teng <[email protected]>
Signed-off-by: Tim Chang <[email protected]>
Co-authored-by: Jason Teng <[email protected]>
Co-authored-by: Jason Teng <[email protected]>
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@timchang514 @Sairakan
3 people authored Dec 19, 2024
1 parent f008a40 commit f8026c7
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Showing 3 changed files with 436 additions and 5 deletions.
100 changes: 95 additions & 5 deletions contrib/babelfishpg_tsql/src/pl_handler.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down Expand Up @@ -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))
{
Expand Down Expand Up @@ -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)))
{
Expand Down Expand Up @@ -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);
}
Expand Down Expand Up @@ -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.
Expand Down Expand Up @@ -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;
Expand All @@ -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)
{
Expand All @@ -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,
Expand Down
210 changes: 210 additions & 0 deletions test/JDBC/expected/temp_table.out
View file
Original file line number Diff line number Diff line change
@@ -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
Expand Down Expand Up @@ -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
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