*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/optimizer/util/tlist.c,v 1.36 1999/07/16 04:59:27 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/optimizer/util/tlist.c,v 1.37 1999/08/09 05:34:13 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
-
-
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "optimizer/clauses.h"
#include "optimizer/tlist.h"
#include "optimizer/var.h"
-static Node *flatten_tlistentry(Node *tlistentry, List *flat_tlist);
+static Node *flatten_tlist_vars_mutator(Node *node, List *flat_tlist);
/*****************************************************************************
* ---------- RELATION node target list routines ----------
/*
* tlistentry_member
- *
- * RETURNS: the leftmost member of sequence "targetlist" that satisfies
- * the predicate "var_equal"
- * MODIFIES: nothing
- * REQUIRES: test = function which can operate on a lispval union
- * var = valid var_node
- * targetlist = valid sequence
+ * Finds the (first) member of the given tlist whose expression is
+ * var_equal() to the given var. Result is NULL if no such member.
*/
TargetEntry *
tlistentry_member(Var *var, List *targetlist)
{
- if (var)
+ if (var && IsA(var, Var))
{
List *temp;
foreach(temp, targetlist)
{
- if (var_equal(var,
- get_expr(lfirst(temp))))
+ if (var_equal(var, get_expr(lfirst(temp))))
return (TargetEntry *) lfirst(temp);
}
}
/*
* matching_tlist_var
- *
- * RETURNS: var node in a target list which is var_equal to 'var',
- * if one exists.
- * REQUIRES: "test" operates on lispval unions,
- *
+ * Same as tlistentry_member(), except returns the tlist expression
+ * rather than its parent TargetEntry node.
*/
Expr *
matching_tlist_var(Var *var, List *targetlist)
return (Expr *) NULL;
}
+/*
+ * tlist_member
+ * Same as tlistentry_member(), except returns the Resdom node
+ * rather than its parent TargetEntry node.
+ */
+Resdom *
+tlist_member(Var *var, List *tlist)
+{
+ TargetEntry *tlentry;
+
+ tlentry = tlistentry_member(var, tlist);
+ if (tlentry)
+ return tlentry->resdom;
+
+ return (Resdom *) NULL;
+}
+
/*
* add_var_to_tlist
* Creates a targetlist entry corresponding to the supplied var node
- *
- * 'var' and adds the new targetlist entry to the targetlist field of
- * 'rel'
- *
- * RETURNS: nothing
- * MODIFIES: vartype and varid fields of leftmost varnode that matches
- * argument "var" (sometimes).
- * CREATES: new var_node iff no matching var_node exists in targetlist
+ * 'var' and adds the new targetlist entry to the targetlist field of
+ * 'rel'. No entry is created if 'var' is already in the tlist.
*/
void
add_var_to_tlist(RelOptInfo *rel, Var *var)
{
- Expr *oldvar;
-
- oldvar = matching_tlist_var(var, rel->targetlist);
-
- /*
- * If 'var' is not already in 'rel's target list, add a new node.
- */
- if (oldvar == NULL)
+ if (tlistentry_member(var, rel->targetlist) == NULL)
{
- List *tlist = rel->targetlist;
- Var *newvar = makeVar(var->varno,
- var->varattno,
- var->vartype,
- var->vartypmod,
- var->varlevelsup,
- var->varno,
- var->varoattno);
-
- rel->targetlist = lappend(tlist,
- create_tl_element(newvar,
- length(tlist) + 1));
-
+ /* XXX is copyObject necessary here? */
+ rel->targetlist = lappend(rel->targetlist,
+ create_tl_element((Var *) copyObject(var),
+ length(rel->targetlist) + 1));
}
}
/*
* create_tl_element
* Creates a target list entry node and its associated (resdom var) pair
- * with its resdom number equal to 'resdomno' and the joinlist field set
- * to 'joinlist'.
- *
- * RETURNS: newly created tlist_entry
- * CREATES: new targetlist entry (always).
+ * with its resdom number equal to 'resdomno'.
*/
TargetEntry *
create_tl_element(Var *var, int resdomno)
* ---------- GENERAL target list routines ----------
*****************************************************************************/
-/*
- * tlist_member
- * Determines whether a var node is already contained within a
- * target list.
- *
- * 'var' is the var node
- * 'tlist' is the target list
- *
- * Returns the resdom entry of the matching var node, or NULL if no match.
- *
- */
-Resdom *
-tlist_member(Var *var, List *tlist)
-{
- if (var)
- {
- List *i;
-
- foreach(i, tlist)
- {
- TargetEntry *tle = (TargetEntry *) lfirst(i);
-
- if (var_equal(var, get_expr(tle)))
- return tle->resdom;
- }
- }
- return (Resdom *) NULL;
-}
-
/*
* Routine to get the resdom out of a targetlist.
*/
/*
* match_varid
- * Searches a target list for an entry with some desired varid.
- *
- * 'varid' is the desired id
- * 'tlist' is the target list that is searched
- *
- * Returns the target list entry (resdom var) of the matching var.
+ * Searches a target list for an entry matching a given var.
*
- * Now checks to make sure array references (in addition to range
- * table indices) are identical - retrieve (a.b[1],a.b[2]) should
- * not be turned into retrieve (a.b[1],a.b[1]).
- *
- * [what used to be varid is now broken up into two fields varnoold and
- * varoattno. Also, nested attnos are long gone. - ay 2/95]
+ * Returns the target list entry (resdom var) of the matching var,
+ * or NULL if no match.
*/
TargetEntry *
match_varid(Var *test_var, List *tlist)
{
List *tl;
- Oid type_var;
- type_var = (Oid) test_var->vartype;
+ Assert(test_var->varlevelsup == 0); /* XXX why? */
- Assert(test_var->varlevelsup == 0);
foreach(tl, tlist)
{
- TargetEntry *entry;
- Var *tlvar;
-
- entry = lfirst(tl);
- tlvar = get_expr(entry);
+ TargetEntry *entry = lfirst(tl);
+ Var *tlvar = get_expr(entry);
if (!IsA(tlvar, Var))
continue;
/*
- * we test the original varno (instead of varno which might be
- * changed to INNER/OUTER.
+ * we test the original varno, instead of varno which might be
+ * changed to INNER/OUTER. XXX is test on vartype necessary?
*/
Assert(tlvar->varlevelsup == 0);
+
if (tlvar->varnoold == test_var->varnoold &&
- tlvar->varoattno == test_var->varoattno)
- {
- if (tlvar->vartype == type_var)
- return entry;
- }
+ tlvar->varoattno == test_var->varoattno &&
+ tlvar->vartype == test_var->vartype)
+ return entry;
}
return NULL;
copy_vars(List *target, List *source)
{
List *result = NIL;
- List *src = NIL;
- List *dest = NIL;
+ List *src;
+ List *dest;
- for (src = source, dest = target; src != NIL &&
- dest != NIL; src = lnext(src), dest = lnext(dest))
+ for (src = source, dest = target;
+ src != NIL && dest != NIL;
+ src = lnext(src), dest = lnext(dest))
{
TargetEntry *temp = makeTargetEntry(((TargetEntry *) lfirst(dest))->resdom,
(Node *) get_expr(lfirst(src)));
{
int last_resdomno = 1;
List *new_tlist = NIL;
- List *tlist_vars = NIL;
- List *temp;
-
- foreach(temp, tlist)
- {
- TargetEntry *temp_entry = (TargetEntry *) lfirst(temp);
-
- tlist_vars = nconc(tlist_vars,
- pull_var_clause((Node *) get_expr(temp_entry)));
- }
+ List *tl;
- foreach(temp, tlist_vars)
+ foreach(tl, tlist)
{
- Var *var = lfirst(temp);
+ TargetEntry *tl_entry = (TargetEntry *) lfirst(tl);
+ List *vlist = pull_var_clause((Node *) get_expr(tl_entry));
+ List *v;
- if (!(tlist_member(var, new_tlist)))
+ foreach(v, vlist)
{
- Resdom *r;
-
- r = makeResdom(last_resdomno,
- var->vartype,
- var->vartypmod,
- NULL,
- (Index) 0,
- (Oid) 0,
- false);
- last_resdomno++;
- new_tlist = lappend(new_tlist, makeTargetEntry(r, (Node *) var));
+ Var *var = lfirst(v);
+
+ if (! tlistentry_member(var, new_tlist))
+ {
+ Resdom *r;
+
+ r = makeResdom(last_resdomno++,
+ var->vartype,
+ var->vartypmod,
+ NULL,
+ (Index) 0,
+ (Oid) 0,
+ false);
+ new_tlist = lappend(new_tlist,
+ makeTargetEntry(r, (Node *) var));
+ }
}
+ freeList(vlist);
}
return new_tlist;
/*
* flatten_tlist_vars
- * Redoes the target list of a query with no nested attributes by
- * replacing vars within computational expressions with vars from
- * the 'flattened' target list of the query.
+ * Redoes the target list of a query by replacing vars within
+ * target expressions with vars from the 'flattened' target list.
*
- * 'full_tlist' is the actual target list
+ * 'full_tlist' is the original target list
* 'flat_tlist' is the flattened (var-only) target list
*
- * Returns the modified actual target list.
+ * Returns the rebuilt target list. The original is not modified.
*
*/
List *
{
TargetEntry *tle = lfirst(x);
- result = lappend(result, makeTargetEntry(tle->resdom,
- flatten_tlistentry((Node *) get_expr(tle),
- flat_tlist)));
+ result = lappend(result,
+ makeTargetEntry(tle->resdom,
+ flatten_tlist_vars_mutator((Node *) get_expr(tle),
+ flat_tlist)));
}
return result;
}
-/*
- * flatten_tlistentry
- * Replaces vars within a target list entry with vars from a flattened
- * target list.
- *
- * 'tlistentry' is the target list entry to be modified
- * 'flat_tlist' is the flattened target list
- *
- * Returns the (modified) target_list entry from the target list.
- *
- */
static Node *
-flatten_tlistentry(Node *tlistentry, List *flat_tlist)
+flatten_tlist_vars_mutator(Node *node, List *flat_tlist)
{
- List *temp;
-
- if (tlistentry == NULL)
+ if (node == NULL)
return NULL;
- else if (IsA(tlistentry, Var))
- return (Node *) get_expr(match_varid((Var *) tlistentry,
+ if (IsA(node, Var))
+ return (Node *) get_expr(match_varid((Var *) node,
flat_tlist));
- else if (single_node(tlistentry))
- return tlistentry;
- else if (IsA(tlistentry, Iter))
- {
- ((Iter *) tlistentry)->iterexpr =
- flatten_tlistentry((Node *) ((Iter *) tlistentry)->iterexpr,
- flat_tlist);
- return tlistentry;
- }
- else if (is_subplan(tlistentry))
- {
- /* do we need to support this case? */
- elog(ERROR, "flatten_tlistentry: subplan case not implemented");
- return tlistentry;
- }
- else if (IsA(tlistentry, Expr))
- {
-
- /*
- * Recursively scan the arguments of an expression. NOTE: this
- * must come after is_subplan() case since subplan is a kind of
- * Expr node.
- */
- foreach(temp, ((Expr *) tlistentry)->args)
- lfirst(temp) = flatten_tlistentry(lfirst(temp), flat_tlist);
- return tlistentry;
- }
- else if (IsA(tlistentry, Aggref))
- {
-
- /*
- * XXX shouldn't this be recursing into the agg's target? Seems to
- * work though, so will leave it alone ... tgl 5/99
- */
- return tlistentry;
- }
- else if (IsA(tlistentry, ArrayRef))
- {
- ArrayRef *aref = (ArrayRef *) tlistentry;
-
- foreach(temp, aref->refupperindexpr)
- lfirst(temp) = flatten_tlistentry(lfirst(temp), flat_tlist);
- foreach(temp, aref->reflowerindexpr)
- lfirst(temp) = flatten_tlistentry(lfirst(temp), flat_tlist);
- aref->refexpr = flatten_tlistentry(aref->refexpr, flat_tlist);
- aref->refassgnexpr = flatten_tlistentry(aref->refassgnexpr, flat_tlist);
-
- return tlistentry;
- }
- else if (case_clause(tlistentry))
- {
- CaseExpr *cexpr = (CaseExpr *) tlistentry;
-
- foreach(temp, cexpr->args)
- {
- CaseWhen *cwhen = (CaseWhen *) lfirst(temp);
-
- cwhen->expr = flatten_tlistentry(cwhen->expr, flat_tlist);
- cwhen->result = flatten_tlistentry(cwhen->result, flat_tlist);
- }
- cexpr->defresult = flatten_tlistentry(cexpr->defresult, flat_tlist);
-
- return tlistentry;
- }
- else
- {
- elog(ERROR, "flatten_tlistentry: Cannot handle node type %d",
- nodeTag(tlistentry));
- return tlistentry;
- }
+ return expression_tree_mutator(node, flatten_tlist_vars_mutator,
+ (void *) flat_tlist);
}
get_groupclause_expr(GroupClause *groupClause, List *targetList)
{
List *l;
- TargetEntry *tle;
foreach(l, targetList)
{
- tle = (TargetEntry *) lfirst(l);
+ TargetEntry *tle = (TargetEntry *) lfirst(l);
if (tle->resdom->resgroupref == groupClause->tleGroupref)
return get_expr(tle);
}
"get_groupclause_expr: GROUP BY expression not found in targetlist");
return NULL;
}
-
-
-/*****************************************************************************
- *
- *****************************************************************************/
-
-/*
- * AddGroupAttrToTlist -
- * append the group attribute to the target list if it's not already
- * in there.
- */
-#ifdef NOT_USED
-/*
- * WARNING!!! If this ever get's used again, the new reference
- * mechanism from group clause to targetlist entry must be implemented
- * here too. Jan
- */
-void
-AddGroupAttrToTlist(List *tlist, List *grpCl)
-{
- List *gl;
- int last_resdomno = length(tlist) + 1;
-
- foreach(gl, grpCl)
- {
- GroupClause *gc = (GroupClause *) lfirst(gl);
- Var *var = gc->grpAttr;
-
- if (!(tlist_member(var, tlist)))
- {
- Resdom *r;
-
- r = makeResdom(last_resdomno,
- var->vartype,
- var->vartypmod,
- NULL,
- (Index) 0,
- (Oid) 0,
- false);
- last_resdomno++;
- tlist = lappend(tlist, makeTargetEntry(r, (Node *) var));
- }
- }
-}
-
-#endif
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