Hi,
On Thu, Sep 25, 2025 at 5:45 PM Jim Jones <jim.jo...@uni-muenster.de> wrote:
>
> A few days ago I reviewed one patch[1] that has a significant overlap
> with this one. Perhaps they should be merged?
>
Thanks for looking into it!
I don't know what exactly is meant by merging. Maybe we should just
apply a current
patch that fixes all problems ?..
> Here my first tests and comments:
> ....
OK, I'll replace "could not" with "cannot" in order to match previous comments.
>
> DROP TABLE still works, but I guess it is the main motivation of
> RVR_OTHER_TEMP_OK :)
Yep, motivation of this decision you can find here [1].
I'll attach a v8 patch that fixes error messages (could not -> cannot).
--
Best regards,
Daniil Davydov
[1] https://www.postgresql.org/message-id/Zx7oLCnqis3FjgCK%40paquier.xyz
From 28250951d1d6888945850aee05f128f590d88c6f Mon Sep 17 00:00:00 2001
From: Daniil Davidov <d.davy...@postgrespro.ru>
Date: Thu, 25 Sep 2025 20:06:40 +0700
Subject: [PATCH v8] Fix accessing other sessions temp tables
---
src/backend/catalog/namespace.c | 56 ++++++++++++++++++++------------
src/backend/commands/tablecmds.c | 3 +-
src/backend/nodes/makefuncs.c | 6 +++-
src/backend/parser/gram.y | 11 ++++++-
src/include/catalog/namespace.h | 2 ++
5 files changed, 55 insertions(+), 23 deletions(-)
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index ed9aeee24bc..6b835dc45c8 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -498,28 +498,44 @@ RangeVarGetRelidExtended(const RangeVar *relation, LOCKMODE lockmode,
*/
if (relation->relpersistence == RELPERSISTENCE_TEMP)
{
- if (!OidIsValid(myTempNamespace))
- relId = InvalidOid; /* this probably can't happen? */
- else
- {
- if (relation->schemaname)
- {
- Oid namespaceId;
+ Oid namespaceId;
- namespaceId = LookupExplicitNamespace(relation->schemaname, missing_ok);
+ if (relation->schemaname)
+ {
+ namespaceId = LookupExplicitNamespace(relation->schemaname, missing_ok);
+ /*
+ * If the user has specified an existing temporary schema
+ * owned by another user.
+ */
+ if (OidIsValid(namespaceId) && namespaceId != myTempNamespace)
+ {
/*
- * For missing_ok, allow a non-existent schema name to
- * return InvalidOid.
+ * We don't allow users to access temp tables of other
+ * sessions except for the case of dropping tables.
*/
- if (namespaceId != myTempNamespace)
+ if (!(flags & RVR_OTHER_TEMP_OK))
ereport(ERROR,
- (errcode(ERRCODE_INVALID_TABLE_DEFINITION),
- errmsg("temporary tables cannot specify a schema name")));
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot not access temporary relations of other sessions")));
}
+ }
+ else
+ {
+ namespaceId = myTempNamespace;
- relId = get_relname_relid(relation->relname, myTempNamespace);
+ /*
+ * If this table was recognized as temporary, it means that we
+ * found it because backend's temporary namespace was specified
+ * in search_path. Thus, MyTempNamespace must contain valid oid.
+ */
+ Assert(OidIsValid(namespaceId));
}
+
+ if (missing_ok && !OidIsValid(namespaceId))
+ relId = InvalidOid;
+ else
+ relId = get_relname_relid(relation->relname, namespaceId);
}
else if (relation->schemaname)
{
@@ -3620,21 +3636,19 @@ get_namespace_oid(const char *nspname, bool missing_ok)
RangeVar *
makeRangeVarFromNameList(const List *names)
{
- RangeVar *rel = makeRangeVar(NULL, NULL, -1);
+ RangeVar *rel;
switch (list_length(names))
{
case 1:
- rel->relname = strVal(linitial(names));
+ rel = makeRangeVar(NULL, strVal(linitial(names)), -1);
break;
case 2:
- rel->schemaname = strVal(linitial(names));
- rel->relname = strVal(lsecond(names));
+ rel = makeRangeVar(strVal(linitial(names)), strVal(lsecond(names)), -1);
break;
case 3:
+ rel = makeRangeVar(strVal(lsecond(names)), strVal(lthird(names)), -1);
rel->catalogname = strVal(linitial(names));
- rel->schemaname = strVal(lsecond(names));
- rel->relname = strVal(lthird(names));
break;
default:
ereport(ERROR,
@@ -3841,6 +3855,8 @@ GetTempNamespaceProcNumber(Oid namespaceId)
return INVALID_PROC_NUMBER; /* no such namespace? */
if (strncmp(nspname, "pg_temp_", 8) == 0)
result = atoi(nspname + 8);
+ else if (strcmp(nspname, "pg_temp") == 0)
+ result = MyProcNumber;
else if (strncmp(nspname, "pg_toast_temp_", 14) == 0)
result = atoi(nspname + 14);
else
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index fc89352b661..aa4a80f3f29 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -1624,7 +1624,8 @@ RemoveRelations(DropStmt *drop)
state.heapOid = InvalidOid;
state.partParentOid = InvalidOid;
- relOid = RangeVarGetRelidExtended(rel, lockmode, RVR_MISSING_OK,
+ relOid = RangeVarGetRelidExtended(rel, lockmode,
+ RVR_MISSING_OK | RVR_OTHER_TEMP_OK,
RangeVarCallbackForDropRelation,
&state);
diff --git a/src/backend/nodes/makefuncs.c b/src/backend/nodes/makefuncs.c
index e2d9e9be41a..62edf24b5c2 100644
--- a/src/backend/nodes/makefuncs.c
+++ b/src/backend/nodes/makefuncs.c
@@ -478,10 +478,14 @@ makeRangeVar(char *schemaname, char *relname, int location)
r->schemaname = schemaname;
r->relname = relname;
r->inh = true;
- r->relpersistence = RELPERSISTENCE_PERMANENT;
r->alias = NULL;
r->location = location;
+ if (r->schemaname && strncmp(r->schemaname, "pg_temp", 7) == 0)
+ r->relpersistence = RELPERSISTENCE_TEMP;
+ else
+ r->relpersistence = RELPERSISTENCE_PERMANENT;
+
return r;
}
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 9fd48acb1f8..36f2f44cabe 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -19406,7 +19406,11 @@ makeRangeVarFromAnyName(List *names, int position, core_yyscan_t yyscanner)
break;
}
- r->relpersistence = RELPERSISTENCE_PERMANENT;
+ if (r->schemaname && strncmp(r->schemaname, "pg_temp", 7) == 0)
+ r->relpersistence = RELPERSISTENCE_TEMP;
+ else
+ r->relpersistence = RELPERSISTENCE_PERMANENT;
+
r->location = position;
return r;
@@ -19446,6 +19450,11 @@ makeRangeVarFromQualifiedName(char *name, List *namelist, int location,
break;
}
+ if (r->schemaname && strncmp(r->schemaname, "pg_temp", 7) == 0)
+ r->relpersistence = RELPERSISTENCE_TEMP;
+ else
+ r->relpersistence = RELPERSISTENCE_PERMANENT;
+
return r;
}
diff --git a/src/include/catalog/namespace.h b/src/include/catalog/namespace.h
index f1423f28c32..b08d55f2c97 100644
--- a/src/include/catalog/namespace.h
+++ b/src/include/catalog/namespace.h
@@ -90,6 +90,8 @@ typedef enum RVROption
RVR_MISSING_OK = 1 << 0, /* don't error if relation doesn't exist */
RVR_NOWAIT = 1 << 1, /* error if relation cannot be locked */
RVR_SKIP_LOCKED = 1 << 2, /* skip if relation cannot be locked */
+ RVR_OTHER_TEMP_OK = 1 << 3 /* don't error if relation is temp relation of
+ other session (needed for DROP command) */
} RVROption;
typedef void (*RangeVarGetRelidCallback) (const RangeVar *relation, Oid relId,
--
2.43.0
