Hi hackers, Thanks for the valuable feedback on my previous patch.
Based on the review comments, I have updated the patch as follows:
- Limited the error trigger only to the case where the original function is IMMUTABLE but the new definition is not.
- Changed the error code to ERRCODE_FEATURE_NOT_SUPPORTED for better semantics.
- Improved code indentation and style to align with project conventions.
- Added a regression test case in create_function_sql.sql to verify the new behavior.
The full updated patch is attached below.
Please take a look at this revised version. I look forward to your feedback and suggestions.
Best regards,
xiaojiluo (Tencent Yunding Lab)
jian he<jian.universal...@gmail.com> 在 2025年7月9日 周三
10:34 写道：
On Mon, Jun 30, 2025 at 5:34 PM sundayjiang(蒋浩天)
<sundayji...@tencent.com> wrote:
>
> The purpose of this patch is to prevent replacing a function via `CREATE
OR REPLACE FUNCTION` with a new definition that is not marked as `IMMUTABLE`,
if the existing function is referenced by an index expression.
>
> Replacing such functions may lead to index corruption or runtime semantic
inconsistencies, especially when the function’s output is not stable for the
same input.
>
> If a function is used in an index, it can only be replaced if it is
declared as `IMMUTABLE`.
>
looking at the right above code ``if (oldproc->prokind != prokind)``
+ if(oldproc->prokind == PROKIND_FUNCTION && volatility !=
PROVOLATILE_IMMUTABLE){
we can change it to
+ if(prokind == PROKIND_FUNCTION
&& oldproc->provolatile ==
PROVOLATILE_IMMUTABLE &&
+ volatility !=
PROVOLATILE_IMMUTABLE)
+ {
curly brace generally begins with a new line.
if (index_found)
+ ereport(ERROR,
+ (errcode(ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST),
+ errmsg("cannot replace function \"%s\" with a non-IMMUTABLE function
because it is used by an index",
+ procedureName)));
Here, errcode ERRCODE_FEATURE_NOT_SUPPORTED would be more appropriate.
you can add a simple test in src/test/regress/sql/create_function_sql.sql
for example:
CREATE OR REPLACE FUNCTION get_a_int(int default 2) RETURNS int
IMMUTABLE AS 'select $1' LANGUAGE sql;
create table t1(a int);
create index on t1((get_a_int(a)));
CREATE OR REPLACE FUNCTION get_a_int(int default 2) RETURNS int AS
'select $1' LANGUAGE sql;
v2-0001-Prevent-replacement-of-a-function-if-it-s-used-in-an.patch
Description: Binary data
