Fix multi-row DEFAULT handling for INSERT ... SELECT rules.

Given an updatable view with a DO ALSO INSERT ... SELECT rule, a
multi-row INSERT ... VALUES query on the view fails if the VALUES list
contains any DEFAULTs that are not replaced by view defaults. This
manifests as an "unrecognized node type" error, or an Assert failure,
in an assert-enabled build.

The reason is that when RewriteQuery() attempts to replace the
remaining DEFAULT items with NULLs in any product queries, using
rewriteValuesRTEToNulls(), it assumes that the VALUES RTE is located
at the same rangetable index in each product query. However, if the
product query is an INSERT ... SELECT, then the VALUES RTE is actually
in the SELECT part of that query (at the same index), rather than the
top-level product query itself.

Fix, by descending to the SELECT in such cases. Note that we can't
simply use getInsertSelectQuery() for this, since that expects to be
given a raw rule action with OLD and NEW placeholder entries, so we
duplicate its logic instead.

While at it, beef up the checks in getInsertSelectQuery() by checking
that the jointree->fromlist node is indeed a RangeTblRef, and that the
RTE it points to has rtekind == RTE_SUBQUERY.

Per bug #17803, from Alexander Lakhin. Back-patch to all supported
branches.

Dean Rasheed, reviewed by Tom Lane.

Discussion: https://postgr.es/m/17803-53c63ed4ecb4eac6%40postgresql.org

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 593c533b449aa7e266312d51d7c524e228cca506..d769ccecb5ee0bd92eb06d1bdacad61f48280fe9 100644 (file)
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -1461,7 +1461,6 @@ rewriteValuesRTEToNulls(Query *parsetree, RangeTblEntry *rte)
    List       *newValues;
    ListCell   *lc;
 
-   Assert(rte->rtekind == RTE_VALUES);
    newValues = NIL;
    foreach(lc, rte->values_lists)
    {
@@ -3747,12 +3746,39 @@ RewriteQuery(Query *parsetree, List *rewrite_events, int orig_rt_length)
            /*
             * Each product query has its own copy of the VALUES RTE at the
             * same index in the rangetable, so we must finalize each one.
+            *
+            * Note that if the product query is an INSERT ... SELECT, then
+            * the VALUES RTE will be at the same index in the SELECT part of
+            * the product query rather than the top-level product query
+            * itself.
             */
            foreach(n, product_queries)
            {
                Query      *pt = (Query *) lfirst(n);
-               RangeTblEntry *values_rte = rt_fetch(values_rte_index,
-                                                    pt->rtable);
+               RangeTblEntry *values_rte;
+
+               if (pt->commandType == CMD_INSERT &&
+                   pt->jointree && IsA(pt->jointree, FromExpr) &&
+                   list_length(pt->jointree->fromlist) == 1)
+               {
+                   Node       *jtnode = (Node *) linitial(pt->jointree->fromlist);
+
+                   if (IsA(jtnode, RangeTblRef))
+                   {
+                       int         rtindex = ((RangeTblRef *) jtnode)->rtindex;
+                       RangeTblEntry *src_rte = rt_fetch(rtindex, pt->rtable);
+
+                       if (src_rte->rtekind == RTE_SUBQUERY &&
+                           src_rte->subquery &&
+                           IsA(src_rte->subquery, Query) &&
+                           src_rte->subquery->commandType == CMD_SELECT)
+                           pt = src_rte->subquery;
+                   }
+               }
+
+               values_rte = rt_fetch(values_rte_index, pt->rtable);
+               if (values_rte->rtekind != RTE_VALUES)
+                   elog(ERROR, "failed to find VALUES RTE in product query");
 
                rewriteValuesRTEToNulls(pt, values_rte);
            }

diff --git a/src/backend/rewrite/rewriteManip.c b/src/backend/rewrite/rewriteManip.c
index a727f41bde34a4ce350d8ac489fc12d356f432d5..506959b7b67a1d2c0117b2bfdcf85c30b6d36feb 100644 (file)
--- a/src/backend/rewrite/rewriteManip.c
+++ b/src/backend/rewrite/rewriteManip.c
@@ -951,12 +951,15 @@ getInsertSelectQuery(Query *parsetree, Query ***subquery_ptr)
    if (list_length(parsetree->jointree->fromlist) != 1)
        elog(ERROR, "expected to find SELECT subquery");
    rtr = (RangeTblRef *) linitial(parsetree->jointree->fromlist);
-   Assert(IsA(rtr, RangeTblRef));
+   if (!IsA(rtr, RangeTblRef))
+       elog(ERROR, "expected to find SELECT subquery");
    selectrte = rt_fetch(rtr->rtindex, parsetree->rtable);
-   selectquery = selectrte->subquery;
-   if (!(selectquery && IsA(selectquery, Query) &&
-         selectquery->commandType == CMD_SELECT))
+   if (!(selectrte->rtekind == RTE_SUBQUERY &&
+         selectrte->subquery &&
+         IsA(selectrte->subquery, Query) &&
+         selectrte->subquery->commandType == CMD_SELECT))
        elog(ERROR, "expected to find SELECT subquery");
+   selectquery = selectrte->subquery;
    if (list_length(selectquery->rtable) >= 2 &&
        strcmp(rt_fetch(PRS2_OLD_VARNO, selectquery->rtable)->eref->aliasname,
               "old") == 0 &&

diff --git a/src/test/regress/expected/updatable_views.out b/src/test/regress/expected/updatable_views.out
index 06f1e64d421e2589bae5bb49d6b46c411bc81dc9..bb8c2389641ac484c06e97c7c4667ebfb2d7adf3 100644 (file)
--- a/src/test/regress/expected/updatable_views.out
+++ b/src/test/regress/expected/updatable_views.out
@@ -3074,6 +3074,25 @@ select * from base_tab_def order by a, c NULLS LAST;
     | View default  |               | View default | 
 (22 rows)
 
+-- Test a DO ALSO INSERT ... SELECT rule
+drop rule base_tab_def_view_ins_rule on base_tab_def_view;
+create rule base_tab_def_view_ins_rule as on insert to base_tab_def_view
+  do also insert into base_tab_def (a, b, e) select new.a, new.b, 'xxx';
+truncate base_tab_def;
+insert into base_tab_def_view values (1, default, default, default, default);
+insert into base_tab_def_view values (2, default, default, default, default),
+                                     (3, default, default, default, default);
+select * from base_tab_def order by a, e nulls first;
+ a |      b       |       c       |      d       |  e  
+---+--------------+---------------+--------------+-----
+ 1 | View default | Table default | View default | 
+ 1 | View default | Table default |              | xxx
+ 2 | View default | Table default | View default | 
+ 2 | View default | Table default |              | xxx
+ 3 | View default | Table default | View default | 
+ 3 | View default | Table default |              | xxx
+(6 rows)
+
 drop view base_tab_def_view;
 drop table base_tab_def;
 -- Test defaults with array assignments

diff --git a/src/test/regress/sql/updatable_views.sql b/src/test/regress/sql/updatable_views.sql
index cc441b9c927614857640092eea5c874e4925e631..b3c09e890ead8e0948325d0ef6aa7a59fba636c2 100644 (file)
--- a/src/test/regress/sql/updatable_views.sql
+++ b/src/test/regress/sql/updatable_views.sql
@@ -1537,6 +1537,16 @@ insert into base_tab_def_view values (15, default, default, default, default),
 insert into base_tab_def_view values (17), (default);
 select * from base_tab_def order by a, c NULLS LAST;
 
+-- Test a DO ALSO INSERT ... SELECT rule
+drop rule base_tab_def_view_ins_rule on base_tab_def_view;
+create rule base_tab_def_view_ins_rule as on insert to base_tab_def_view
+  do also insert into base_tab_def (a, b, e) select new.a, new.b, 'xxx';
+truncate base_tab_def;
+insert into base_tab_def_view values (1, default, default, default, default);
+insert into base_tab_def_view values (2, default, default, default, default),
+                                     (3, default, default, default, default);
+select * from base_tab_def order by a, e nulls first;
+
 drop view base_tab_def_view;
 drop table base_tab_def;