Re: Forbid to DROP temp tables of other sessions

[Steven Niu]

在 2025/3/17 18:56, Daniil Davydov 写道:
Hi,

On Mon, Mar 17, 2025 at 5:33 PM Steven Niu <niush...@gmail.com> wrote:

I mean RangeVarGetRelidExtended(), you deleted the following code:

if (!OidIsValid(myTempNamespace))
             relId = InvalidOid; /* this probably can't happen? */

Hm, I got it. Let's start with the fact that the comment "this
probably can't happen?" is incorrect. Even if we don't have a
temporary namespace in our session, we still can specify "pg_temp_N"
in the psql query.
Next, if relation->schemaname is pg_temp, then we firstly call
LookupExplicitNamespace, where you can find if
(!OidIsValid(myTempNamespace)) check.

--
Best regards,
Daniil Davydov

If the (relation->relpersistence == RELPERSISTENCE_TEMP) can ensure the 
myTempNamespace is always valid, then my comment can be ignored. 
Otherwise I think the modified RangeVarGetRelidExtended() should keep 
check of myTempNamespace, like this:

if (relation->relpersistence == RELPERSISTENCE_TEMP)
{
  Oid namespaceId;

 if (!OidIsValid(myTempNamespace))
     relId = InvalidOid; /* this probably can't happen? */
 else
 {
   if (relation->schemaname)
   {
     namespaceId = LookupExplicitNamespace(relation->schemaname, 
missing_ok);
     if (namespaceId != myTempNamespace)
     {
         ereport(ERROR,
                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                  errmsg("could not access temporary relations of other 
sessions")));
     }
  }
  else
  {
     namespaceId = myTempNamespace;
     Assert(OidIsValid(namespaceId));
  }
  if (missing_ok && !OidIsValid(namespaceId))
     relId = InvalidOid;
  else
     relId = get_relname_relid(relation->relname, namespaceId);
 }
...
...

Thanks,
Steven