Better error message for unsupported replication cases
In [1]/messages/by-id/CANhtRiamAgYt1A-Nh4=mU3E1UhG9XPgB+X6mW1DWqa93vUXW9A@mail.gmail.com there's a complaint that if you try to logically replicate
a partitioned table from v13-or-later to v12-or-earlier, you get
"table XXX not found on publisher", which is pretty confusing
because the publisher certainly does have such a table. That
happens because fetch_remote_table_info is too aggressive about
filtering by relkind and doesn't see the relation at all.
c314c147c improved that, but it wasn't back-patched. I propose
putting the attached into v10-v12. Maybe the error message
could be bikeshedded ... is "non-table relation" terminology
that we use in user-facing messages?
regards, tom lane
[1]: /messages/by-id/CANhtRiamAgYt1A-Nh4=mU3E1UhG9XPgB+X6mW1DWqa93vUXW9A@mail.gmail.com
Attachments:
handle-unsupported-relkind-better.patchtext/x-diff; charset=us-ascii; name=handle-unsupported-relkind-better.patchDownload
diff --git a/src/backend/replication/logical/tablesync.c b/src/backend/replication/logical/tablesync.c
index 2db88dc41a..61244e08fa 100644
--- a/src/backend/replication/logical/tablesync.c
+++ b/src/backend/replication/logical/tablesync.c
@@ -646,9 +646,10 @@ fetch_remote_table_info(char *nspname, char *relname,
WalRcvExecResult *res;
StringInfoData cmd;
TupleTableSlot *slot;
- Oid tableRow[2] = {OIDOID, CHAROID};
+ Oid tableRow[3] = {OIDOID, CHAROID, CHAROID};
Oid attrRow[4] = {TEXTOID, OIDOID, INT4OID, BOOLOID};
bool isnull;
+ char relkind;
int natt;
lrel->nspname = nspname;
@@ -656,13 +657,12 @@ fetch_remote_table_info(char *nspname, char *relname,
/* First fetch Oid and replica identity. */
initStringInfo(&cmd);
- appendStringInfo(&cmd, "SELECT c.oid, c.relreplident"
+ appendStringInfo(&cmd, "SELECT c.oid, c.relreplident, c.relkind"
" FROM pg_catalog.pg_class c"
" INNER JOIN pg_catalog.pg_namespace n"
" ON (c.relnamespace = n.oid)"
" WHERE n.nspname = %s"
- " AND c.relname = %s"
- " AND c.relkind = 'r'",
+ " AND c.relname = %s",
quote_literal_cstr(nspname),
quote_literal_cstr(relname));
res = walrcv_exec(LogRepWorkerWalRcvConn, cmd.data,
@@ -683,6 +683,19 @@ fetch_remote_table_info(char *nspname, char *relname,
Assert(!isnull);
lrel->replident = DatumGetChar(slot_getattr(slot, 2, &isnull));
Assert(!isnull);
+ relkind = DatumGetChar(slot_getattr(slot, 3, &isnull));
+ Assert(!isnull);
+
+ /*
+ * Newer PG versions allow things that aren't plain tables to appear in
+ * publications. We don't handle that in this version, but try to provide
+ * a useful error message.
+ */
+ if (relkind != RELKIND_RELATION)
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("cannot sync from non-table relation \"%s.%s\"",
+ nspname, relname)));
ExecDropSingleTupleTableSlot(slot);
walrcv_clear_result(res);
On Tue, Feb 15, 2022 at 3:42 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
In [1] there's a complaint that if you try to logically replicate
a partitioned table from v13-or-later to v12-or-earlier, you get
"table XXX not found on publisher", which is pretty confusing
because the publisher certainly does have such a table. That
happens because fetch_remote_table_info is too aggressive about
filtering by relkind and doesn't see the relation at all.
c314c147c improved that, but it wasn't back-patched. I propose
putting the attached into v10-v12. Maybe the error message
could be bikeshedded ... is "non-table relation" terminology
that we use in user-facing messages?
The other option could be "logical replication source relation
\"%s.%s\" is not a table". We use a similar message in
CheckSubscriptionRelkind.
--
With Regards,
Amit Kapila.
Amit Kapila <amit.kapila16@gmail.com> writes:
On Tue, Feb 15, 2022 at 3:42 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
... Maybe the error message
could be bikeshedded ... is "non-table relation" terminology
that we use in user-facing messages?
The other option could be "logical replication source relation
\"%s.%s\" is not a table". We use a similar message in
CheckSubscriptionRelkind.
Works for me, I'll do it like that if there are no objections.
regards, tom lane