Improve subscriber's error message for wrong publication relkind.

Pre-v13 versions only support logical replication from plain tables,
while v13 and later also allow partitioned tables to be published.
If you tried to subscribe an older server to such a publication,
you got "table XXX not found on publisher", which is pretty
unhelpful/confusing.  Arrange to deliver a more on-point error
message.  As commit c314c147c did in v13, remove the relkind check
from the query WHERE clause altogether, so that "not there"
is distinguishable from "wrong relkind".

Per report from Radoslav Nedyalkov.  Patch v10-v12.

Discussion: https://postgr.es/m/2952568.1644876730@sss.pgh.pa.us

diff --git a/src/backend/replication/logical/tablesync.c b/src/backend/replication/logical/tablesync.c
index f386838ffa7703c642192a22465b3d5d2a3f54ab..d8b3e984b1575a78679c8ad43ad9dd02868361ce 100644 (file)
--- a/src/backend/replication/logical/tablesync.c
+++ b/src/backend/replication/logical/tablesync.c
@@ -659,9 +659,10 @@ 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;
@@ -669,13 +670,12 @@ 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,
@@ -696,6 +696,19 @@ 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("logical replication source relation \"%s.%s\" is not a table",
+                       nspname, relname)));
 
    ExecDropSingleTupleTableSlot(slot);
    walrcv_clear_result(res);