Re: [PATCH] Add pg_get_policy_ddl() function to reconstruct CREATE POLICY statement

On Thu, Oct 16, 2025 at 8:51 PM Akshay Joshi
<akshay(dot)joshi(at)enterprisedb(dot)com> wrote:
>
> Please find attached the v3 patch, which resolves all compilation errors and warnings.
>

drop table if exists t, ts, ts1;
create table t(a int);
CREATE POLICY p0 ON t FOR ALL TO PUBLIC USING (a % 2 = 1);
SELECT pg_get_policy_ddl('t', 'p0', false);

pg_get_policy_ddl
---------------------------------------------------------------------
CREATE POLICY p0 ON t AS PERMISSIVE FOR ALL USING (((a % 2) = 1));
(1 row)

"TO PUBLIC" part is missing, maybe it's ok.

SELECT pg_get_policy_ddl(-1, 'p0', false);
ERROR: could not open relation with OID 4294967295
as I mentioned in a nearby thread [1], this should be NULL instead of ERROR.
[1] https://postgr.es/m/CACJufxGbE4uJWu1YuqdmOx+7PMBpHvX_fbRMmHu=r4SrsuW9tg@mail.gmail.com

IMHO, get_formatted_string is not needed, most of the time, if pretty is true,
we append "\t" and "\n", for that we can simply do
```
appendStringInfo(&buf, "CREATE POLICY %s ON %s ",
quote_identifier(NameStr(*policyName)),
generate_qualified_relation_name(policy_form->polrelid));
if (pretty)
appendStringInfoString(buf, "\t\n");
```

in pg_get_triggerdef_worker, I found the below code pattern:
/*
* In non-pretty mode, always schema-qualify the target table name for
* safety. In pretty mode, schema-qualify only if not visible.
*/
appendStringInfo(&buf, " ON %s ",
pretty ?
generate_relation_name(trigrec->tgrelid, NIL) :
generate_qualified_relation_name(trigrec->tgrelid));

maybe we can apply it too while construct query string:
"CREATE POLICY %s ON %s",