diff --git a/src/backend/optimizer/util/var.c b/src/backend/optimizer/util/var.c
index 7eaf8d27bf08bf5dd1776d203876adb8396c73b3..5f736ad6c4060ff4d7dabb3844a04185e01fa3ef 100644
--- a/src/backend/optimizer/util/var.c
+++ b/src/backend/optimizer/util/var.c
@@ -654,7 +654,7 @@ flatten_join_alias_vars_mutator(Node *node,
newvar = (Node *) lfirst(lv);
attnum++;
/* Ignore dropped columns */
- if (IsA(newvar, Const))
+ if (newvar == NULL)
continue;
newvar = copyObject(newvar);
@@ -687,6 +687,7 @@ flatten_join_alias_vars_mutator(Node *node,
/* Expand join alias reference */
Assert(var->varattno > 0);
newvar = (Node *) list_nth(rte->joinaliasvars, var->varattno - 1);
+ Assert(newvar != NULL);
newvar = copyObject(newvar);
/*
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index a9254c8c3a2e33b7c293ef51c53c78a797b1d4f1..42de89f510190877b1f6fa357efb08c81eb7acc9 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -24,6 +24,7 @@
#include "funcapi.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
+#include "optimizer/clauses.h"
#include "parser/parsetree.h"
#include "parser/parse_relation.h"
#include "parser/parse_type.h"
@@ -749,14 +750,15 @@ markRTEForSelectPriv(ParseState *pstate, RangeTblEntry *rte,
* The aliasvar could be either a Var or a COALESCE expression,
* but in the latter case we should already have marked the two
* referent variables as being selected, due to their use in the
- * JOIN clause. So we need only be concerned with the simple Var
- * case.
+ * JOIN clause. So we need only be concerned with the Var case.
+ * But we do need to drill down through implicit coercions.
*/
Var *aliasvar;
Assert(col > 0 && col <= list_length(rte->joinaliasvars));
aliasvar = (Var *) list_nth(rte->joinaliasvars, col - 1);
- if (IsA(aliasvar, Var))
+ aliasvar = (Var *) strip_implicit_coercions((Node *) aliasvar);
+ if (aliasvar && IsA(aliasvar, Var))
markVarForSelectPriv(pstate, aliasvar, NULL);
}
}
@@ -1841,10 +1843,10 @@ expandRTE(RangeTblEntry *rte, int rtindex, int sublevels_up,
* deleted columns in the join; but we have to check since
* this routine is also used by the rewriter, and joins
* found in stored rules might have join columns for
- * since-deleted columns. This will be signaled by a NULL
- * Const in the alias-vars list.
+ * since-deleted columns. This will be signaled by a null
+ * pointer in the alias-vars list.
*/
- if (IsA(avar, Const))
+ if (avar == NULL)
{
if (include_dropped)
{
@@ -1852,8 +1854,16 @@ expandRTE(RangeTblEntry *rte, int rtindex, int sublevels_up,
*colnames = lappend(*colnames,
makeString(pstrdup("")));
if (colvars)
+ {
+ /*
+ * Can't use join's column type here (it might
+ * be dropped!); but it doesn't really matter
+ * what type the Const claims to be.
+ */
*colvars = lappend(*colvars,
- copyObject(avar));
+ makeNullConst(INT4OID, -1,
+ InvalidOid));
+ }
}
continue;
}
@@ -2242,6 +2252,7 @@ get_rte_attribute_type(RangeTblEntry *rte, AttrNumber attnum,
Assert(attnum > 0 && attnum <= list_length(rte->joinaliasvars));
aliasvar = (Node *) list_nth(rte->joinaliasvars, attnum - 1);
+ Assert(aliasvar != NULL);
*vartype = exprType(aliasvar);
*vartypmod = exprTypmod(aliasvar);
*varcollid = exprCollation(aliasvar);
@@ -2304,7 +2315,7 @@ get_rte_attribute_is_dropped(RangeTblEntry *rte, AttrNumber attnum)
* but one in a stored rule might contain columns that were
* dropped from the underlying tables, if said columns are
* nowhere explicitly referenced in the rule. This will be
- * signaled to us by a NULL Const in the joinaliasvars list.
+ * signaled to us by a null pointer in the joinaliasvars list.
*/
Var *aliasvar;
@@ -2313,7 +2324,7 @@ get_rte_attribute_is_dropped(RangeTblEntry *rte, AttrNumber attnum)
elog(ERROR, "invalid varattno %d", attnum);
aliasvar = (Var *) list_nth(rte->joinaliasvars, attnum - 1);
- result = IsA(aliasvar, Const);
+ result = (aliasvar == NULL);
}
break;
case RTE_FUNCTION:
diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c
index ca20e77ce6d1b09ff0a2012f7d3084d33c40543d..9c6c202c8e6ef16a981fdafa8945741ca70cd709 100644
--- a/src/backend/parser/parse_target.c
+++ b/src/backend/parser/parse_target.c
@@ -311,6 +311,7 @@ markTargetListOrigin(ParseState *pstate, TargetEntry *tle,
Assert(attnum > 0 && attnum <= list_length(rte->joinaliasvars));
aliasvar = (Var *) list_nth(rte->joinaliasvars, attnum - 1);
+ /* We intentionally don't strip implicit coercions here */
markTargetListOrigin(pstate, tle, aliasvar, netlevelsup);
}
break;
@@ -1461,6 +1462,8 @@ expandRecordVariable(ParseState *pstate, Var *var, int levelsup)
/* Join RTE --- recursively inspect the alias variable */
Assert(attnum > 0 && attnum <= list_length(rte->joinaliasvars));
expr = (Node *) list_nth(rte->joinaliasvars, attnum - 1);
+ Assert(expr != NULL);
+ /* We intentionally don't strip implicit coercions here */
if (IsA(expr, Var))
return expandRecordVariable(pstate, (Var *) expr, netlevelsup);
/* else fall through to inspect the expression */
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 7f527bd74a281247616ac84870940157c82d76ad..3c7974adc72152ba4640baa95c4aed1ed15c3d9a 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -91,9 +91,8 @@ static Query *fireRIRrules(Query *parsetree, List *activeRIRs,
* such a list in a stored rule to include references to dropped columns.
* (If the column is not explicitly referenced anywhere else in the query,
* the dependency mechanism won't consider it used by the rule and so won't
- * prevent the column drop.) To support get_rte_attribute_is_dropped(),
- * we replace join alias vars that reference dropped columns with NULL Const
- * nodes.
+ * prevent the column drop.) To support get_rte_attribute_is_dropped(), we
+ * replace join alias vars that reference dropped columns with null pointers.
*
* (In PostgreSQL 8.0, we did not do this processing but instead had
* get_rte_attribute_is_dropped() recurse to detect dropped columns in joins.
@@ -160,8 +159,8 @@ AcquireRewriteLocks(Query *parsetree, bool forUpdatePushedDown)
/*
* Scan the join's alias var list to see if any columns have
- * been dropped, and if so replace those Vars with NULL
- * Consts.
+ * been dropped, and if so replace those Vars with null
+ * pointers.
*
* Since a join has only two inputs, we can expect to see
* multiple references to the same input RTE; optimize away
@@ -172,16 +171,20 @@ AcquireRewriteLocks(Query *parsetree, bool forUpdatePushedDown)
curinputrte = NULL;
foreach(ll, rte->joinaliasvars)
{
- Var *aliasvar = (Var *) lfirst(ll);
+ Var *aliasitem = (Var *) lfirst(ll);
+ Var *aliasvar = aliasitem;
+
+ /* Look through any implicit coercion */
+ aliasvar = (Var *) strip_implicit_coercions((Node *) aliasvar);
/*
* If the list item isn't a simple Var, then it must
* represent a merged column, ie a USING column, and so it
* couldn't possibly be dropped, since it's referenced in
- * the join clause. (Conceivably it could also be a NULL
- * constant already? But that's OK too.)
+ * the join clause. (Conceivably it could also be a null
+ * pointer already? But that's OK too.)
*/
- if (IsA(aliasvar, Var))
+ if (aliasvar && IsA(aliasvar, Var))
{
/*
* The elements of an alias list have to refer to
@@ -205,15 +208,11 @@ AcquireRewriteLocks(Query *parsetree, bool forUpdatePushedDown)
if (get_rte_attribute_is_dropped(curinputrte,
aliasvar->varattno))
{
- /*
- * can't use vartype here, since that might be a
- * now-dropped type OID, but it doesn't really
- * matter what type the Const claims to be.
- */
- aliasvar = (Var *) makeNullConst(INT4OID, -1, InvalidOid);
+ /* Replace the join alias item with a NULL */
+ aliasitem = NULL;
}
}
- newaliasvars = lappend(newaliasvars, aliasvar);
+ newaliasvars = lappend(newaliasvars, aliasitem);
}
rte->joinaliasvars = newaliasvars;
break;
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 40b565a11d6ddf40b3cd8e692e625efe1f6dc3a7..cecb542727193cea1bb6ed805f73e6e619c88e78 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -235,6 +235,7 @@ typedef struct
* child RTE's attno and rightattnos[i] is zero; and conversely for a
* column of the right child. But for merged columns produced by JOIN
* USING/NATURAL JOIN, both leftattnos[i] and rightattnos[i] are nonzero.
+ * Also, if the column has been dropped, both are zero.
*
* If it's a JOIN USING, usingNames holds the alias names selected for the
* merged columns (these might be different from the original USING list,
@@ -3053,6 +3054,13 @@ set_join_column_names(deparse_namespace *dpns, RangeTblEntry *rte,
char *colname = colinfo->colnames[i];
char *real_colname;
+ /* Ignore dropped column (only possible for non-merged column) */
+ if (colinfo->leftattnos[i] == 0 && colinfo->rightattnos[i] == 0)
+ {
+ Assert(colname == NULL);
+ continue;
+ }
+
/* Get the child column name */
if (colinfo->leftattnos[i] > 0)
real_colname = leftcolinfo->colnames[colinfo->leftattnos[i] - 1];
@@ -3061,15 +3069,9 @@ set_join_column_names(deparse_namespace *dpns, RangeTblEntry *rte,
else
{
/* We're joining system columns --- use eref name */
- real_colname = (char *) list_nth(rte->eref->colnames, i);
- }
-
- /* Ignore dropped columns (only possible for non-merged column) */
- if (real_colname == NULL)
- {
- Assert(colname == NULL);
- continue;
+ real_colname = strVal(list_nth(rte->eref->colnames, i));
}
+ Assert(real_colname != NULL);
/* In an unnamed join, just report child column names as-is */
if (rte->alias == NULL)
@@ -3402,7 +3404,14 @@ identify_join_columns(JoinExpr *j, RangeTblEntry *jrte,
{
Var *aliasvar = (Var *) lfirst(lc);
- if (IsA(aliasvar, Var))
+ /* get rid of any implicit coercion above the Var */
+ aliasvar = (Var *) strip_implicit_coercions((Node *) aliasvar);
+
+ if (aliasvar == NULL)
+ {
+ /* It's a dropped column; nothing to do here */
+ }
+ else if (IsA(aliasvar, Var))
{
Assert(aliasvar->varlevelsup == 0);
Assert(aliasvar->varattno != 0);
@@ -3422,15 +3431,8 @@ identify_join_columns(JoinExpr *j, RangeTblEntry *jrte,
*/
}
else
- {
- /*
- * Although NULL constants can appear in joinaliasvars lists
- * during planning, we shouldn't see any here, since the Query
- * tree hasn't been through AcquireRewriteLocks().
- */
elog(ERROR, "unrecognized node type in join alias vars: %d",
(int) nodeTag(aliasvar));
- }
i++;
}
@@ -5359,7 +5361,8 @@ get_variable(Var *var, int levelsup, bool istoplevel, deparse_context *context)
Var *aliasvar;
aliasvar = (Var *) list_nth(rte->joinaliasvars, attnum - 1);
- if (IsA(aliasvar, Var))
+ /* we intentionally don't strip implicit coercions here */
+ if (aliasvar && IsA(aliasvar, Var))
{
return get_variable(aliasvar, var->varlevelsup + levelsup,
istoplevel, context);
@@ -5670,6 +5673,8 @@ get_name_for_var_field(Var *var, int fieldno,
elog(ERROR, "cannot decompile join alias var in plan tree");
Assert(attnum > 0 && attnum <= list_length(rte->joinaliasvars));
expr = (Node *) list_nth(rte->joinaliasvars, attnum - 1);
+ Assert(expr != NULL);
+ /* we intentionally don't strip implicit coercions here */
if (IsA(expr, Var))
return get_name_for_var_field((Var *) expr, fieldno,
var->varlevelsup + levelsup,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 9415e2c636eab741e2216e6c23dc929e7f4f9494..b4013e893dcf2dd11f86459a5a658410baadfae7 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -660,7 +660,7 @@ typedef struct XmlSerialize
* a stored rule might contain entries for columns dropped since the rule
* was created. (This is only possible for columns not actually referenced
* in the rule.) When loading a stored rule, we replace the joinaliasvars
- * items for any such columns with NULL Consts. (We can't simply delete
+ * items for any such columns with null pointers. (We can't simply delete
* them from the joinaliasvars list, because that would affect the attnums
* of Vars referencing the rest of the list.)
*
@@ -731,13 +731,19 @@ typedef struct RangeTblEntry
/*
* Fields valid for a join RTE (else NULL/zero):
*
- * joinaliasvars is a list of Vars or COALESCE expressions corresponding
- * to the columns of the join result. An alias Var referencing column K
- * of the join result can be replaced by the K'th element of joinaliasvars
- * --- but to simplify the task of reverse-listing aliases correctly, we
- * do not do that until planning time. In a Query loaded from a stored
- * rule, it is also possible for joinaliasvars items to be NULL Consts,
- * denoting columns dropped since the rule was made.
+ * joinaliasvars is a list of (usually) Vars corresponding to the columns
+ * of the join result. An alias Var referencing column K of the join
+ * result can be replaced by the K'th element of joinaliasvars --- but to
+ * simplify the task of reverse-listing aliases correctly, we do not do
+ * that until planning time. In detail: an element of joinaliasvars can
+ * be a Var of one of the join's input relations, or such a Var with an
+ * implicit coercion to the join's output column type, or a COALESCE
+ * expression containing the two input column Vars (possibly coerced).
+ * Within a Query loaded from a stored rule, it is also possible for
+ * joinaliasvars items to be null pointers, which are placeholders for
+ * (necessarily unreferenced) columns dropped since the rule was made.
+ * Also, once planning begins, joinaliasvars items can be almost anything,
+ * as a result of subquery-flattening substitutions.
*/
JoinType jointype; /* type of join */
List *joinaliasvars; /* list of alias-var expansions */
diff --git a/src/test/regress/expected/create_view.out b/src/test/regress/expected/create_view.out
index 4fa774950345808d9455abf06fddbed15933dfaf..8b451429674a6153dcf914ab2753787365cd6cb8 100644
--- a/src/test/regress/expected/create_view.out
+++ b/src/test/regress/expected/create_view.out
@@ -1243,6 +1243,33 @@ select pg_get_viewdef('vv4', true);
FULL JOIN tt8 tt8y(x_1, z, z2) USING (x_1);
(1 row)
+--
+-- Also check dropping a column that existed when the view was made
+--
+create table tt9 (x int, xx int, y int);
+create table tt10 (x int, z int);
+create view vv5 as select x,y,z from tt9 join tt10 using(x);
+select pg_get_viewdef('vv5', true);
+ pg_get_viewdef
+-------------------------
+ SELECT tt9.x, +
+ tt9.y, +
+ tt10.z +
+ FROM tt9 +
+ JOIN tt10 USING (x);
+(1 row)
+
+alter table tt9 drop column xx;
+select pg_get_viewdef('vv5', true);
+ pg_get_viewdef
+-------------------------
+ SELECT tt9.x, +
+ tt9.y, +
+ tt10.z +
+ FROM tt9 +
+ JOIN tt10 USING (x);
+(1 row)
+
-- clean up all the random objects we made above
set client_min_messages = warning;
DROP SCHEMA temp_view_test CASCADE;
diff --git a/src/test/regress/sql/create_view.sql b/src/test/regress/sql/create_view.sql
index 3d85d9cfdc50b454fb38d8a742770eda1e119a41..4fbd5a5e6f8baa3d41f1a201fbb99ad4bc3bf3da 100644
--- a/src/test/regress/sql/create_view.sql
+++ b/src/test/regress/sql/create_view.sql
@@ -389,6 +389,21 @@ select pg_get_viewdef('vv2', true);
select pg_get_viewdef('vv3', true);
select pg_get_viewdef('vv4', true);
+--
+-- Also check dropping a column that existed when the view was made
+--
+
+create table tt9 (x int, xx int, y int);
+create table tt10 (x int, z int);
+
+create view vv5 as select x,y,z from tt9 join tt10 using(x);
+
+select pg_get_viewdef('vv5', true);
+
+alter table tt9 drop column xx;
+
+select pg_get_viewdef('vv5', true);
+
-- clean up all the random objects we made above
set client_min_messages = warning;
DROP SCHEMA temp_view_test CASCADE;