Clean up handling of dropped columns in NAMEDTUPLESTORE RTEs.

The NAMEDTUPLESTORE patch piggybacked on the infrastructure for
TABLEFUNC/VALUES/CTE RTEs, none of which can ever have dropped columns,
so the possibility was ignored most places.  Fix that, including adding a
specification to parsenodes.h about what it's supposed to look like.

In passing, clean up assorted comments that hadn't been maintained
properly by said patch.

Per bug #14799 from Philippe Beaudoin.  Back-patch to v10.

Discussion: https://postgr.es/m/20170906120005.25630.84360@wrigleys.postgresql.org

diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c
index c8e2b67da42cccc60a8db6ff59f549f658b636b5..7125082812aa576d41a7f72925f02f61824c52fd 100644 (file)
--- a/src/backend/optimizer/util/relnode.c
+++ b/src/backend/optimizer/util/relnode.c
@@ -178,8 +178,8 @@ build_simple_rel(PlannerInfo *root, int relid, RelOptInfo *parent)
                case RTE_NAMEDTUPLESTORE:
 
                        /*
-                        * Subquery, function, tablefunc, or values list --- set up attr
-                        * range and arrays
+                        * Subquery, function, tablefunc, values list, CTE, or ENR --- set
+                        * up attr range and arrays
                         *
                         * Note: 0 is included in range to support whole-row Vars
                         */

diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index 684a50d3df66af05baaae1cf7d753abb2b97b758..a0ad01104a829044c982d8db3dfffc370747d5f2 100644 (file)
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -2014,11 +2014,13 @@ addRangeTableEntryForENR(ParseState *pstate,
 
        /*
         * Build the list of effective column names using user-supplied aliases
-        * and/or actual column names.  Also build the cannibalized fields.
+        * and/or actual column names.
         */
        tupdesc = ENRMetadataGetTupDesc(enrmd);
        rte->eref = makeAlias(refname, NIL);
        buildRelationAliases(tupdesc, alias, rte->eref);
+
+       /* Record additional data for ENR, including column type info */
        rte->enrname = enrmd->name;
        rte->enrtuples = enrmd->enrtuples;
        rte->coltypes = NIL;
@@ -2026,19 +2028,26 @@ addRangeTableEntryForENR(ParseState *pstate,
        rte->colcollations = NIL;
        for (attno = 1; attno <= tupdesc->natts; ++attno)
        {
-               if (tupdesc->attrs[attno - 1]->atttypid == InvalidOid &&
-                       !(tupdesc->attrs[attno - 1]->attisdropped))
-                       elog(ERROR, "atttypid was invalid for column which has not been dropped from \"%s\"",
-                                rv->relname);
-               rte->coltypes =
-                       lappend_oid(rte->coltypes,
-                                               tupdesc->attrs[attno - 1]->atttypid);
-               rte->coltypmods =
-                       lappend_int(rte->coltypmods,
-                                               tupdesc->attrs[attno - 1]->atttypmod);
-               rte->colcollations =
-                       lappend_oid(rte->colcollations,
-                                               tupdesc->attrs[attno - 1]->attcollation);
+               Form_pg_attribute att = TupleDescAttr(tupdesc, attno - 1);
+
+               if (att->attisdropped)
+               {
+                       /* Record zeroes for a dropped column */
+                       rte->coltypes = lappend_oid(rte->coltypes, InvalidOid);
+                       rte->coltypmods = lappend_int(rte->coltypmods, 0);
+                       rte->colcollations = lappend_oid(rte->colcollations, InvalidOid);
+               }
+               else
+               {
+                       /* Let's just make sure we can tell this isn't dropped */
+                       if (att->atttypid == InvalidOid)
+                               elog(ERROR, "atttypid is invalid for non-dropped column in \"%s\"",
+                                        rv->relname);
+                       rte->coltypes = lappend_oid(rte->coltypes, att->atttypid);
+                       rte->coltypmods = lappend_int(rte->coltypmods, att->atttypmod);
+                       rte->colcollations = lappend_oid(rte->colcollations,
+                                                                                        att->attcollation);
+               }
        }
 
        /*
@@ -2417,7 +2426,7 @@ expandRTE(RangeTblEntry *rte, int rtindex, int sublevels_up,
                case RTE_CTE:
                case RTE_NAMEDTUPLESTORE:
                        {
-                               /* Tablefunc, Values or CTE RTE */
+                               /* Tablefunc, Values, CTE, or ENR RTE */
                                ListCell   *aliasp_item = list_head(rte->eref->colnames);
                                ListCell   *lct;
                                ListCell   *lcm;
@@ -2437,23 +2446,43 @@ expandRTE(RangeTblEntry *rte, int rtindex, int sublevels_up,
                                        if (colnames)
                                        {
                                                /* Assume there is one alias per output column */
-                                               char       *label = strVal(lfirst(aliasp_item));
+                                               if (OidIsValid(coltype))
+                                               {
+                                                       char       *label = strVal(lfirst(aliasp_item));
+
+                                                       *colnames = lappend(*colnames,
+                                                                                               makeString(pstrdup(label)));
+                                               }
+                                               else if (include_dropped)
+                                                       *colnames = lappend(*colnames,
+                                                                                               makeString(pstrdup("")));
 
-                                               *colnames = lappend(*colnames,
-                                                                                       makeString(pstrdup(label)));
                                                aliasp_item = lnext(aliasp_item);
                                        }
 
                                        if (colvars)
                                        {
-                                               Var                *varnode;
+                                               if (OidIsValid(coltype))
+                                               {
+                                                       Var                *varnode;
 
-                                               varnode = makeVar(rtindex, varattno,
-                                                                                 coltype, coltypmod, colcoll,
-                                                                                 sublevels_up);
-                                               varnode->location = location;
+                                                       varnode = makeVar(rtindex, varattno,
+                                                                                         coltype, coltypmod, colcoll,
+                                                                                         sublevels_up);
+                                                       varnode->location = location;
 
-                                               *colvars = lappend(*colvars, varnode);
+                                                       *colvars = lappend(*colvars, varnode);
+                                               }
+                                               else if (include_dropped)
+                                               {
+                                                       /*
+                                                        * It doesn't really matter what type the Const
+                                                        * claims to be.
+                                                        */
+                                                       *colvars = lappend(*colvars,
+                                                                                          makeNullConst(INT4OID, -1,
+                                                                                                                        InvalidOid));
+                                               }
                                        }
                                }
                        }
@@ -2832,13 +2861,21 @@ get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,
                case RTE_NAMEDTUPLESTORE:
                        {
                                /*
-                                * tablefunc, VALUES or CTE RTE --- get type info from lists
-                                * in the RTE
+                                * tablefunc, VALUES, CTE, or ENR RTE --- get type info from
+                                * lists in the RTE
                                 */
                                Assert(attnum > 0 && attnum <= list_length(rte->coltypes));
                                *vartype = list_nth_oid(rte->coltypes, attnum - 1);
                                *vartypmod = list_nth_int(rte->coltypmods, attnum - 1);
                                *varcollid = list_nth_oid(rte->colcollations, attnum - 1);
+
+                               /* For ENR, better check for dropped column */
+                               if (!OidIsValid(*vartype))
+                                       ereport(ERROR,
+                                                       (errcode(ERRCODE_UNDEFINED_COLUMN),
+                                                        errmsg("column %d of relation \"%s\" does not exist",
+                                                                       attnum,
+                                                                       rte->eref->aliasname)));
                        }
                        break;
                default:
@@ -2889,15 +2926,11 @@ get_rte_attribute_is_dropped(RangeTblEntry *rte, AttrNumber attnum)
                        break;
                case RTE_NAMEDTUPLESTORE:
                        {
-                               Assert(rte->enrname);
-
-                               /*
-                                * We checked when we loaded coltypes for the tuplestore that
-                                * InvalidOid was only used for dropped columns, so it is safe
-                                * to count on that here.
-                                */
-                               result =
-                                       ((list_nth_oid(rte->coltypes, attnum - 1) == InvalidOid));
+                               /* Check dropped-ness by testing for valid coltype */
+                               if (attnum <= 0 ||
+                                       attnum > list_length(rte->coltypes))
+                                       elog(ERROR, "invalid varattno %d", attnum);
+                               result = !OidIsValid((list_nth_oid(rte->coltypes, attnum - 1)));
                        }
                        break;
                case RTE_JOIN:

diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c
index 0a70539fb11c52ce03a51ab7f827c603e1ba3bfd..64a1b75ccc4c77c2a0f99574462a8d098ab247e8 100644 (file)
--- a/src/backend/parser/parse_target.c
+++ b/src/backend/parser/parse_target.c
@@ -1509,8 +1509,8 @@ expandRecordVariable(ParseState *pstate, Var *var, int levelsup)
                case RTE_NAMEDTUPLESTORE:
 
                        /*
-                        * This case should not occur: a column of a table or values list
-                        * shouldn't have type RECORD.  Fall through and fail (most
+                        * This case should not occur: a column of a table, values list,
+                        * or ENR shouldn't have type RECORD.  Fall through and fail (most
                         * likely) at the bottom.
                         */
                        break;

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index e9bd64b7a88838231d7d2df6e49290ea716ed4a0..37d4ef043d789254017c13da3355d29101340f1a 100644 (file)
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -6844,8 +6844,8 @@ get_name_for_var_field(Var *var, int fieldno,
                case RTE_NAMEDTUPLESTORE:
 
                        /*
-                        * This case should not occur: a column of a table or values list
-                        * shouldn't have type RECORD.  Fall through and fail (most
+                        * This case should not occur: a column of a table, values list,
+                        * or ENR shouldn't have type RECORD.  Fall through and fail (most
                         * likely) at the bottom.
                         */
                        break;

diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 5f2a4a75dab02ffbd4fa07a53f18ce25012d4bed..ef6753e31ad4945620c967a9f486b151d1cf4a7c 100644 (file)
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1025,6 +1025,11 @@ typedef struct RangeTblEntry
         * from the catalogs if 'relid' was supplied, but we'd still need these
         * for TupleDesc-based ENRs, so we might as well always store the type
         * info here).
+        *
+        * For ENRs only, we have to consider the possibility of dropped columns.
+        * A dropped column is included in these lists, but it will have zeroes in
+        * all three lists (as well as an empty-string entry in eref).  Testing
+        * for zero coltype is the standard way to detect a dropped column.
         */
        List       *coltypes;           /* OID list of column type OIDs */
        List       *coltypmods;         /* integer list of column typmods */