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 8ad0b4a6697801daeaba2d439e3239feba38a6b7..c7b2695ebb348822c7296f5390ac6431441fb63c 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 88b3e88a21fd4bed351ae7ed71f0a8ccf40b2869..4c5c684b44149d8b487fb0e87aa3f8c6669263a0 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;
@@ -2028,16 +2030,24 @@ addRangeTableEntryForENR(ParseState *pstate,
    {
        Form_pg_attribute att = TupleDescAttr(tupdesc, attno - 1);
 
-       if (att->atttypid == InvalidOid &&
-           !(att->attisdropped))
-           elog(ERROR, "atttypid was invalid for column which has not been dropped from \"%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);
+       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);
+       }
    }
 
    /*
@@ -2416,7 +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;
@@ -2436,23 +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));
+                       }
                    }
                }
            }
@@ -2831,13 +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:
@@ -2888,15 +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 c3cb0357ca9077d823a1a81973ab7a696fb8ae57..fce863600cec34066d0d70bf180ec2c6ff2457f0 100644 (file)
--- a/src/backend/parser/parse_target.c
+++ b/src/backend/parser/parse_target.c
@@ -1511,8 +1511,8 @@ 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 43646d2c4f8558f75a72e2e3dd5c3c6e0bd64cd5..f9ea7ed771d1e9a98d56e6e65bbb01ed0ab99707 100644 (file)
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -6846,8 +6846,8 @@ 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 */