vacuumdb: Skip temporary tables in query to build list of relations

Running vacuumdb with a non-superuser while another user has created a
temporary table would lead to a mid-flight permission failure,
interrupting the operation.  vacuum_rel() skips temporary relations of
other backends, and it makes no sense for vacuumdb to know about these
relations, so let's switch it to ignore temporary relations entirely.

Adding a qual in the query based on relpersistence simplifies the
generation of its WHERE clause in vacuum_one_database(), per se the
removal of "has_where".

Author: VaibhaveS, Michael Paquier
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/CAM_eQjwfAR=y3G1fGyS1U9FTmc+FyJm9amNfY2QCZBnDDbNPZg@mail.gmail.com
Backpatch-through: 12

diff --git a/src/bin/scripts/vacuumdb.c b/src/bin/scripts/vacuumdb.c
index 97ec3ad0e992760e257e9b1f02746db529afb8f9..151580ec4490f28fc2dce3899ceed262273a96dc 100644 (file)
--- a/src/bin/scripts/vacuumdb.c
+++ b/src/bin/scripts/vacuumdb.c
@@ -390,7 +390,6 @@ vacuum_one_database(const ConnParams *cparams,
        bool            failed = false;
        bool            parallel = concurrentCons > 1;
        bool            tables_listed = false;
-       bool            has_where = false;
        const char *stage_commands[] = {
                "SET default_statistics_target=1; SET vacuum_cost_delay=0;",
                "SET default_statistics_target=10; RESET vacuum_cost_delay;",
@@ -515,11 +514,21 @@ vacuum_one_database(const ConnParams *cparams,
                                          " LEFT JOIN pg_catalog.pg_class t"
                                          " ON c.reltoastrelid OPERATOR(pg_catalog.=) t.oid\n");
 
-       /* Used to match the tables listed by the user */
+       /*
+        * Used to match the tables listed by the user, completing the JOIN
+        * clause.
+        */
        if (tables_listed)
                appendPQExpBuffer(&catalog_query, " JOIN listed_tables"
                                                  " ON listed_tables.table_oid OPERATOR(pg_catalog.=) c.oid\n");
 
+       /*
+        * Exclude temporary tables, beginning the WHERE clause.
+        */
+       appendPQExpBufferStr(&catalog_query,
+                                                " WHERE c.relpersistence != " CppAsString2(RELPERSISTENCE_TEMP));
+
+
        /*
         * If no tables were listed, filter for the relevant relation types.  If
         * tables were given via --table, don't bother filtering by relation type.
@@ -528,10 +537,9 @@ vacuum_one_database(const ConnParams *cparams,
         */
        if (!tables_listed)
        {
-               appendPQExpBuffer(&catalog_query, " WHERE c.relkind OPERATOR(pg_catalog.=) ANY (array["
+               appendPQExpBuffer(&catalog_query, " AND c.relkind OPERATOR(pg_catalog.=) ANY (array["
                                                  CppAsString2(RELKIND_RELATION) ", "
                                                  CppAsString2(RELKIND_MATVIEW) "])\n");
-               has_where = true;
        }
 
        /*
@@ -544,25 +552,23 @@ vacuum_one_database(const ConnParams *cparams,
        if (vacopts->min_xid_age != 0)
        {
                appendPQExpBuffer(&catalog_query,
-                                                 " %s GREATEST(pg_catalog.age(c.relfrozenxid),"
+                                                 " AND GREATEST(pg_catalog.age(c.relfrozenxid),"
                                                  " pg_catalog.age(t.relfrozenxid)) "
                                                  " OPERATOR(pg_catalog.>=) '%d'::pg_catalog.int4\n"
                                                  " AND c.relfrozenxid OPERATOR(pg_catalog.!=)"
                                                  " '0'::pg_catalog.xid\n",
-                                                 has_where ? "AND" : "WHERE", vacopts->min_xid_age);
-               has_where = true;
+                                                 vacopts->min_xid_age);
        }
 
        if (vacopts->min_mxid_age != 0)
        {
                appendPQExpBuffer(&catalog_query,
-                                                 " %s GREATEST(pg_catalog.mxid_age(c.relminmxid),"
+                                                 " AND GREATEST(pg_catalog.mxid_age(c.relminmxid),"
                                                  " pg_catalog.mxid_age(t.relminmxid)) OPERATOR(pg_catalog.>=)"
                                                  " '%d'::pg_catalog.int4\n"
                                                  " AND c.relminmxid OPERATOR(pg_catalog.!=)"
                                                  " '0'::pg_catalog.xid\n",
-                                                 has_where ? "AND" : "WHERE", vacopts->min_mxid_age);
-               has_where = true;
+                                                 vacopts->min_mxid_age);
        }
 
        /*