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 c884ffc8878c9546c31309f5e184815193c707f9..1792c35e592f07e765122239f0d85acc9cc29d07 100644 (file)
--- a/src/bin/scripts/vacuumdb.c
+++ b/src/bin/scripts/vacuumdb.c
@@ -447,7 +447,6 @@ vacuum_one_database(ConnParams *cparams,
    int         ntups;
    bool        failed = false;
    bool        tables_listed = false;
-   bool        has_where = false;
    const char *initcmd;
    const char *stage_commands[] = {
        "SET default_statistics_target=1; SET vacuum_cost_delay=0;",
@@ -612,11 +611,21 @@ vacuum_one_database(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)
        appendPQExpBufferStr(&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.
@@ -625,10 +634,9 @@ vacuum_one_database(ConnParams *cparams,
     */
    if (!tables_listed)
    {
-       appendPQExpBufferStr(&catalog_query, " WHERE c.relkind OPERATOR(pg_catalog.=) ANY (array["
+       appendPQExpBufferStr(&catalog_query, " AND c.relkind OPERATOR(pg_catalog.=) ANY (array["
                             CppAsString2(RELKIND_RELATION) ", "
                             CppAsString2(RELKIND_MATVIEW) "])\n");
-       has_where = true;
    }
 
    /*
@@ -641,25 +649,23 @@ vacuum_one_database(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);
    }
 
    /*