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-rw-r--r--src/backend/parser/analyze.c3
-rw-r--r--src/backend/parser/parse_agg.c8
-rw-r--r--src/backend/parser/parse_clause.c235
-rw-r--r--src/backend/parser/parse_coerce.c2
-rw-r--r--src/backend/parser/parse_expr.c5
-rw-r--r--src/backend/parser/parse_relation.c40
-rw-r--r--src/backend/parser/parse_target.c2
7 files changed, 231 insertions, 64 deletions
diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 4a817b75ad8..e892df98194 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -676,6 +676,7 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
sub_pstate->p_rtable = sub_rtable;
sub_pstate->p_rteperminfos = sub_rteperminfos;
sub_pstate->p_joinexprs = NIL; /* sub_rtable has no joins */
+ sub_pstate->p_nullingrels = NIL;
sub_pstate->p_namespace = sub_namespace;
sub_pstate->p_resolve_unknowns = false;
@@ -857,7 +858,7 @@ transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
/*
* Generate list of Vars referencing the RTE
*/
- exprList = expandNSItemVars(nsitem, 0, -1, NULL);
+ exprList = expandNSItemVars(pstate, nsitem, 0, -1, NULL);
/*
* Re-apply any indirection on the target column specs to the Vars
diff --git a/src/backend/parser/parse_agg.c b/src/backend/parser/parse_agg.c
index caecaaae504..4fbf80c2713 100644
--- a/src/backend/parser/parse_agg.c
+++ b/src/backend/parser/parse_agg.c
@@ -1167,7 +1167,7 @@ parseCheckAggregates(ParseState *pstate, Query *qry)
* entries are RTE_JOIN kind.
*/
if (hasJoinRTEs)
- groupClauses = (List *) flatten_join_alias_vars(qry,
+ groupClauses = (List *) flatten_join_alias_vars(NULL, qry,
(Node *) groupClauses);
/*
@@ -1211,7 +1211,7 @@ parseCheckAggregates(ParseState *pstate, Query *qry)
groupClauses, hasJoinRTEs,
have_non_var_grouping);
if (hasJoinRTEs)
- clause = flatten_join_alias_vars(qry, clause);
+ clause = flatten_join_alias_vars(NULL, qry, clause);
check_ungrouped_columns(clause, pstate, qry,
groupClauses, groupClauseCommonVars,
have_non_var_grouping,
@@ -1222,7 +1222,7 @@ parseCheckAggregates(ParseState *pstate, Query *qry)
groupClauses, hasJoinRTEs,
have_non_var_grouping);
if (hasJoinRTEs)
- clause = flatten_join_alias_vars(qry, clause);
+ clause = flatten_join_alias_vars(NULL, qry, clause);
check_ungrouped_columns(clause, pstate, qry,
groupClauses, groupClauseCommonVars,
have_non_var_grouping,
@@ -1551,7 +1551,7 @@ finalize_grouping_exprs_walker(Node *node,
Index ref = 0;
if (context->hasJoinRTEs)
- expr = flatten_join_alias_vars(context->qry, expr);
+ expr = flatten_join_alias_vars(NULL, context->qry, expr);
/*
* Each expression must match a grouping entry at the current
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index bafa5bb3813..f61f7947552 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -52,7 +52,8 @@
#include "utils/syscache.h"
-static int extractRemainingColumns(ParseNamespaceColumn *src_nscolumns,
+static int extractRemainingColumns(ParseState *pstate,
+ ParseNamespaceColumn *src_nscolumns,
List *src_colnames,
List **src_colnos,
List **res_colnames, List **res_colvars,
@@ -75,9 +76,11 @@ static ParseNamespaceItem *getNSItemForSpecialRelationTypes(ParseState *pstate,
static Node *transformFromClauseItem(ParseState *pstate, Node *n,
ParseNamespaceItem **top_nsitem,
List **namespace);
-static Var *buildVarFromNSColumn(ParseNamespaceColumn *nscol);
+static Var *buildVarFromNSColumn(ParseState *pstate,
+ ParseNamespaceColumn *nscol);
static Node *buildMergedJoinVar(ParseState *pstate, JoinType jointype,
Var *l_colvar, Var *r_colvar);
+static void markRelsAsNulledBy(ParseState *pstate, Node *n, int jindex);
static void setNamespaceColumnVisibility(List *namespace, bool cols_visible);
static void setNamespaceLateralState(List *namespace,
bool lateral_only, bool lateral_ok);
@@ -251,7 +254,8 @@ setTargetTable(ParseState *pstate, RangeVar *relation,
* Returns the number of columns added.
*/
static int
-extractRemainingColumns(ParseNamespaceColumn *src_nscolumns,
+extractRemainingColumns(ParseState *pstate,
+ ParseNamespaceColumn *src_nscolumns,
List *src_colnames,
List **src_colnos,
List **res_colnames, List **res_colvars,
@@ -287,7 +291,8 @@ extractRemainingColumns(ParseNamespaceColumn *src_nscolumns,
*src_colnos = lappend_int(*src_colnos, attnum);
*res_colnames = lappend(*res_colnames, lfirst(lc));
*res_colvars = lappend(*res_colvars,
- buildVarFromNSColumn(src_nscolumns + attnum - 1));
+ buildVarFromNSColumn(pstate,
+ src_nscolumns + attnum - 1));
/* Copy the input relation's nscolumn data for this column */
res_nscolumns[colcount] = src_nscolumns[attnum - 1];
colcount++;
@@ -1288,8 +1293,7 @@ transformFromClauseItem(ParseState *pstate, Node *n,
{
/*
* JOIN/USING (or NATURAL JOIN, as transformed above). Transform
- * the list into an explicit ON-condition, and generate a list of
- * merged result columns.
+ * the list into an explicit ON-condition.
*/
List *ucols = j->usingClause;
List *l_usingvars = NIL;
@@ -1307,8 +1311,6 @@ transformFromClauseItem(ParseState *pstate, Node *n,
int r_index = -1;
Var *l_colvar,
*r_colvar;
- Node *u_colvar;
- ParseNamespaceColumn *res_nscolumn;
Assert(u_colname[0] != '\0');
@@ -1372,17 +1374,109 @@ transformFromClauseItem(ParseState *pstate, Node *n,
u_colname)));
r_colnos = lappend_int(r_colnos, r_index + 1);
- l_colvar = buildVarFromNSColumn(l_nscolumns + l_index);
+ /* Build Vars to use in the generated JOIN ON clause */
+ l_colvar = buildVarFromNSColumn(pstate, l_nscolumns + l_index);
l_usingvars = lappend(l_usingvars, l_colvar);
- r_colvar = buildVarFromNSColumn(r_nscolumns + r_index);
+ r_colvar = buildVarFromNSColumn(pstate, r_nscolumns + r_index);
r_usingvars = lappend(r_usingvars, r_colvar);
+ /*
+ * While we're here, add column names to the res_colnames
+ * list. It's a bit ugly to do this here while the
+ * corresponding res_colvars entries are not made till later,
+ * but doing this later would require an additional traversal
+ * of the usingClause list.
+ */
res_colnames = lappend(res_colnames, lfirst(ucol));
+ }
+
+ /* Construct the generated JOIN ON clause */
+ j->quals = transformJoinUsingClause(pstate,
+ l_usingvars,
+ r_usingvars);
+ }
+ else if (j->quals)
+ {
+ /* User-written ON-condition; transform it */
+ j->quals = transformJoinOnClause(pstate, j, my_namespace);
+ }
+ else
+ {
+ /* CROSS JOIN: no quals */
+ }
+
+ /*
+ * If this is an outer join, now mark the appropriate child RTEs as
+ * being nulled by this join. We have finished processing the child
+ * join expressions as well as the current join's quals, which deal in
+ * non-nulled input columns. All future references to those RTEs will
+ * see possibly-nulled values, and we should mark generated Vars to
+ * account for that. In particular, the join alias Vars that we're
+ * about to build should reflect the nulling effects of this join.
+ *
+ * A difficulty with doing this is that we need the join's RT index,
+ * which we don't officially have yet. However, no other RTE can get
+ * made between here and the addRangeTableEntryForJoin call, so we can
+ * predict what the assignment will be. (Alternatively, we could call
+ * addRangeTableEntryForJoin before we have all the data computed, but
+ * this seems less ugly.)
+ */
+ j->rtindex = list_length(pstate->p_rtable) + 1;
+
+ switch (j->jointype)
+ {
+ case JOIN_INNER:
+ break;
+ case JOIN_LEFT:
+ markRelsAsNulledBy(pstate, j->rarg, j->rtindex);
+ break;
+ case JOIN_FULL:
+ markRelsAsNulledBy(pstate, j->larg, j->rtindex);
+ markRelsAsNulledBy(pstate, j->rarg, j->rtindex);
+ break;
+ case JOIN_RIGHT:
+ markRelsAsNulledBy(pstate, j->larg, j->rtindex);
+ break;
+ default:
+ /* shouldn't see any other types here */
+ elog(ERROR, "unrecognized join type: %d",
+ (int) j->jointype);
+ break;
+ }
+
+ /*
+ * Now we can construct join alias expressions for the USING columns.
+ */
+ if (j->usingClause)
+ {
+ ListCell *lc1,
+ *lc2;
+
+ /* Scan the colnos lists to recover info from the previous loop */
+ forboth(lc1, l_colnos, lc2, r_colnos)
+ {
+ int l_index = lfirst_int(lc1) - 1;
+ int r_index = lfirst_int(lc2) - 1;
+ Var *l_colvar,
+ *r_colvar;
+ Node *u_colvar;
+ ParseNamespaceColumn *res_nscolumn;
+
+ /*
+ * Note we re-build these Vars: they might have different
+ * varnullingrels than the ones made in the previous loop.
+ */
+ l_colvar = buildVarFromNSColumn(pstate, l_nscolumns + l_index);
+ r_colvar = buildVarFromNSColumn(pstate, r_nscolumns + r_index);
+
+ /* Construct the join alias Var for this column */
u_colvar = buildMergedJoinVar(pstate,
j->jointype,
l_colvar,
r_colvar);
res_colvars = lappend(res_colvars, u_colvar);
+
+ /* Construct column's res_nscolumns[] entry */
res_nscolumn = res_nscolumns + res_colindex;
res_colindex++;
if (u_colvar == (Node *) l_colvar)
@@ -1400,47 +1494,45 @@ transformFromClauseItem(ParseState *pstate, Node *n,
/*
* Merged column is not semantically equivalent to either
* input, so it needs to be referenced as the join output
- * column. We don't know the join's varno yet, so we'll
- * replace these zeroes below.
+ * column.
*/
- res_nscolumn->p_varno = 0;
+ res_nscolumn->p_varno = j->rtindex;
res_nscolumn->p_varattno = res_colindex;
res_nscolumn->p_vartype = exprType(u_colvar);
res_nscolumn->p_vartypmod = exprTypmod(u_colvar);
res_nscolumn->p_varcollid = exprCollation(u_colvar);
- res_nscolumn->p_varnosyn = 0;
+ res_nscolumn->p_varnosyn = j->rtindex;
res_nscolumn->p_varattnosyn = res_colindex;
}
}
-
- j->quals = transformJoinUsingClause(pstate,
- l_usingvars,
- r_usingvars);
- }
- else if (j->quals)
- {
- /* User-written ON-condition; transform it */
- j->quals = transformJoinOnClause(pstate, j, my_namespace);
- }
- else
- {
- /* CROSS JOIN: no quals */
}
/* Add remaining columns from each side to the output columns */
res_colindex +=
- extractRemainingColumns(l_nscolumns, l_colnames, &l_colnos,
+ extractRemainingColumns(pstate,
+ l_nscolumns, l_colnames, &l_colnos,
&res_colnames, &res_colvars,
res_nscolumns + res_colindex);
res_colindex +=
- extractRemainingColumns(r_nscolumns, r_colnames, &r_colnos,
+ extractRemainingColumns(pstate,
+ r_nscolumns, r_colnames, &r_colnos,
&res_colnames, &res_colvars,
res_nscolumns + res_colindex);
+ /* If join has an alias, it syntactically hides all inputs */
+ if (j->alias)
+ {
+ for (k = 0; k < res_colindex; k++)
+ {
+ ParseNamespaceColumn *nscol = res_nscolumns + k;
+
+ nscol->p_varnosyn = j->rtindex;
+ nscol->p_varattnosyn = k + 1;
+ }
+ }
+
/*
* Now build an RTE and nsitem for the result of the join.
- * res_nscolumns isn't totally done yet, but that's OK because
- * addRangeTableEntryForJoin doesn't examine it, only store a pointer.
*/
nsitem = addRangeTableEntryForJoin(pstate,
res_colnames,
@@ -1454,31 +1546,16 @@ transformFromClauseItem(ParseState *pstate, Node *n,
j->alias,
true);
- j->rtindex = nsitem->p_rtindex;
+ /* Verify that we correctly predicted the join's RT index */
+ Assert(j->rtindex == nsitem->p_rtindex);
+ /* Cross-check number of columns, too */
+ Assert(res_colindex == list_length(nsitem->p_names->colnames));
/*
- * Now that we know the join RTE's rangetable index, we can fix up the
- * res_nscolumns data in places where it should contain that.
+ * Save a link to the JoinExpr in the proper element of p_joinexprs.
+ * Since we maintain that list lazily, it may be necessary to fill in
+ * empty entries before we can add the JoinExpr in the right place.
*/
- Assert(res_colindex == list_length(nsitem->p_names->colnames));
- for (k = 0; k < res_colindex; k++)
- {
- ParseNamespaceColumn *nscol = res_nscolumns + k;
-
- /* fill in join RTI for merged columns */
- if (nscol->p_varno == 0)
- nscol->p_varno = j->rtindex;
- if (nscol->p_varnosyn == 0)
- nscol->p_varnosyn = j->rtindex;
- /* if join has an alias, it syntactically hides all inputs */
- if (j->alias)
- {
- nscol->p_varnosyn = j->rtindex;
- nscol->p_varattnosyn = k + 1;
- }
- }
-
- /* make a matching link to the JoinExpr for later use */
for (k = list_length(pstate->p_joinexprs) + 1; k < j->rtindex; k++)
pstate->p_joinexprs = lappend(pstate->p_joinexprs, NULL);
pstate->p_joinexprs = lappend(pstate->p_joinexprs, j);
@@ -1547,10 +1624,13 @@ transformFromClauseItem(ParseState *pstate, Node *n,
* buildVarFromNSColumn -
* build a Var node using ParseNamespaceColumn data
*
- * We assume varlevelsup should be 0, and no location is specified
+ * This is used to construct joinaliasvars entries.
+ * We can assume varlevelsup should be 0, and no location is specified.
+ * Note also that no column SELECT privilege is requested here; that would
+ * happen only if the column is actually referenced in the query.
*/
static Var *
-buildVarFromNSColumn(ParseNamespaceColumn *nscol)
+buildVarFromNSColumn(ParseState *pstate, ParseNamespaceColumn *nscol)
{
Var *var;
@@ -1564,6 +1644,10 @@ buildVarFromNSColumn(ParseNamespaceColumn *nscol)
/* makeVar doesn't offer parameters for these, so set by hand: */
var->varnosyn = nscol->p_varnosyn;
var->varattnosyn = nscol->p_varattnosyn;
+
+ /* ... and update varnullingrels */
+ markNullableIfNeeded(pstate, var);
+
return var;
}
@@ -1676,6 +1760,47 @@ buildMergedJoinVar(ParseState *pstate, JoinType jointype,
}
/*
+ * markRelsAsNulledBy -
+ * Mark the given jointree node and its children as nulled by join jindex
+ */
+static void
+markRelsAsNulledBy(ParseState *pstate, Node *n, int jindex)
+{
+ int varno;
+ ListCell *lc;
+
+ /* Note: we can't see FromExpr here */
+ if (IsA(n, RangeTblRef))
+ {
+ varno = ((RangeTblRef *) n)->rtindex;
+ }
+ else if (IsA(n, JoinExpr))
+ {
+ JoinExpr *j = (JoinExpr *) n;
+
+ /* recurse to children */
+ markRelsAsNulledBy(pstate, j->larg, jindex);
+ markRelsAsNulledBy(pstate, j->rarg, jindex);
+ varno = j->rtindex;
+ }
+ else
+ {
+ elog(ERROR, "unrecognized node type: %d", (int) nodeTag(n));
+ varno = 0; /* keep compiler quiet */
+ }
+
+ /*
+ * Now add jindex to the p_nullingrels set for relation varno. Since we
+ * maintain the p_nullingrels list lazily, we might need to extend it to
+ * make the varno'th entry exist.
+ */
+ while (list_length(pstate->p_nullingrels) < varno)
+ pstate->p_nullingrels = lappend(pstate->p_nullingrels, NULL);
+ lc = list_nth_cell(pstate->p_nullingrels, varno - 1);
+ lfirst(lc) = bms_add_member((Bitmapset *) lfirst(lc), jindex);
+}
+
+/*
* setNamespaceColumnVisibility -
* Convenience subroutine to update cols_visible flags in a namespace list.
*/
diff --git a/src/backend/parser/parse_coerce.c b/src/backend/parser/parse_coerce.c
index 34757da0fa6..52787b67943 100644
--- a/src/backend/parser/parse_coerce.c
+++ b/src/backend/parser/parse_coerce.c
@@ -1042,7 +1042,7 @@ coerce_record_to_complex(ParseState *pstate, Node *node,
ParseNamespaceItem *nsitem;
nsitem = GetNSItemByRangeTablePosn(pstate, rtindex, sublevels_up);
- args = expandNSItemVars(nsitem, sublevels_up, vlocation, NULL);
+ args = expandNSItemVars(pstate, nsitem, sublevels_up, vlocation, NULL);
}
else
ereport(ERROR,
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 53e904ca6d4..7ff41acb846 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -2478,6 +2478,9 @@ transformWholeRowRef(ParseState *pstate, ParseNamespaceItem *nsitem,
/* location is not filled in by makeWholeRowVar */
result->location = location;
+ /* mark Var if it's nulled by any outer joins */
+ markNullableIfNeeded(pstate, result);
+
/* mark relation as requiring whole-row SELECT access */
markVarForSelectPriv(pstate, result);
@@ -2505,6 +2508,8 @@ transformWholeRowRef(ParseState *pstate, ParseNamespaceItem *nsitem,
rowexpr->colnames = copyObject(nsitem->p_names->colnames);
rowexpr->location = location;
+ /* XXX we ought to mark the row as possibly nullable */
+
return (Node *) rowexpr;
}
}
diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c
index b490541f03d..52b4a6e89df 100644
--- a/src/backend/parser/parse_relation.c
+++ b/src/backend/parser/parse_relation.c
@@ -763,6 +763,9 @@ scanNSItemForColumn(ParseState *pstate, ParseNamespaceItem *nsitem,
}
var->location = location;
+ /* Mark Var if it's nulled by any outer joins */
+ markNullableIfNeeded(pstate, var);
+
/* Require read access to the column */
markVarForSelectPriv(pstate, var);
@@ -1024,6 +1027,35 @@ searchRangeTableForCol(ParseState *pstate, const char *alias, const char *colnam
}
/*
+ * markNullableIfNeeded
+ * If the RTE referenced by the Var is nullable by outer join(s)
+ * at this point in the query, set var->varnullingrels to show that.
+ */
+void
+markNullableIfNeeded(ParseState *pstate, Var *var)
+{
+ int rtindex = var->varno;
+ Bitmapset *relids;
+
+ /* Find the appropriate pstate */
+ for (int lv = 0; lv < var->varlevelsup; lv++)
+ pstate = pstate->parentParseState;
+
+ /* Find currently-relevant join relids for the Var's rel */
+ if (rtindex > 0 && rtindex <= list_length(pstate->p_nullingrels))
+ relids = (Bitmapset *) list_nth(pstate->p_nullingrels, rtindex - 1);
+ else
+ relids = NULL;
+
+ /*
+ * Merge with any already-declared nulling rels. (Typically there won't
+ * be any, but let's get it right if there are.)
+ */
+ if (relids != NULL)
+ var->varnullingrels = bms_union(var->varnullingrels, relids);
+}
+
+/*
* markRTEForSelectPriv
* Mark the specified column of the RTE with index rtindex
* as requiring SELECT privilege
@@ -3087,7 +3119,7 @@ expandTupleDesc(TupleDesc tupdesc, Alias *eref, int count, int offset,
* the list elements mustn't be modified.
*/
List *
-expandNSItemVars(ParseNamespaceItem *nsitem,
+expandNSItemVars(ParseState *pstate, ParseNamespaceItem *nsitem,
int sublevels_up, int location,
List **colnames)
{
@@ -3123,6 +3155,10 @@ expandNSItemVars(ParseNamespaceItem *nsitem,
var->varnosyn = nscol->p_varnosyn;
var->varattnosyn = nscol->p_varattnosyn;
var->location = location;
+
+ /* ... and update varnullingrels */
+ markNullableIfNeeded(pstate, var);
+
result = lappend(result, var);
if (colnames)
*colnames = lappend(*colnames, colnameval);
@@ -3158,7 +3194,7 @@ expandNSItemAttrs(ParseState *pstate, ParseNamespaceItem *nsitem,
*var;
List *te_list = NIL;
- vars = expandNSItemVars(nsitem, sublevels_up, location, &names);
+ vars = expandNSItemVars(pstate, nsitem, sublevels_up, location, &names);
/*
* Require read access to the table. This is normally redundant with the
diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c
index 0ca6beccb8a..25781db5c1d 100644
--- a/src/backend/parser/parse_target.c
+++ b/src/backend/parser/parse_target.c
@@ -1371,7 +1371,7 @@ ExpandSingleTable(ParseState *pstate, ParseNamespaceItem *nsitem,
List *vars;
ListCell *l;
- vars = expandNSItemVars(nsitem, sublevels_up, location, NULL);
+ vars = expandNSItemVars(pstate, nsitem, sublevels_up, location, NULL);
/*
* Require read access to the table. This is normally redundant with
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-20 14:43:00 +0000