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Use Params, rather than run-time-modified Const nodes, to handle
sublink results and COPY's domain constraint checking. A Const that isn't really constant is just a Bad Idea(tm). Remove hacks in parse_coerce and other places that were needed because of the former klugery.
1 parent ac47950 commit ea0b5c8

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9 files changed

+165
-189
lines changed

9 files changed

+165
-189
lines changed

‎src/backend/commands/copy.c

Lines changed: 19 additions & 23 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
*
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.182 2002/11/25 21:29:34 tgl Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/commands/copy.c,v 1.183 2002/11/26 03:01:57 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -749,7 +749,6 @@ CopyFrom(Relation rel, List *attnumlist, bool binary, bool oids,
749749
FmgrInfo *in_functions;
750750
Oid *elements;
751751
Node **constraintexprs;
752-
Const **constraintconsts;
753752
bool hasConstraints = false;
754753
int i;
755754
List *cur;
@@ -805,7 +804,6 @@ CopyFrom(Relation rel, List *attnumlist, bool binary, bool oids,
805804
defmap = (int *) palloc(num_phys_attrs * sizeof(int));
806805
defexprs = (Node **) palloc(num_phys_attrs * sizeof(Node *));
807806
constraintexprs = (Node **) palloc0(num_phys_attrs * sizeof(Node *));
808-
constraintconsts = (Const **) palloc(num_phys_attrs * sizeof(Const *));
809807

810808
for (i = 0; i < num_phys_attrs; i++)
811809
{
@@ -840,36 +838,29 @@ CopyFrom(Relation rel, List *attnumlist, bool binary, bool oids,
840838
/* If it's a domain type, get info on domain constraints */
841839
if (get_typtype(attr[i]->atttypid) == 'd')
842840
{
843-
Const *con;
841+
Param *prm;
844842
Node *node;
845843

846844
/*
847845
* Easiest way to do this is to use parse_coerce.c to set up
848846
* an expression that checks the constraints. (At present,
849847
* the expression might contain a length-coercion-function call
850848
* and/or ConstraintTest nodes.) The bottom of the expression
851-
* is a Const node that we fill in with the actual datum during
849+
* is a Param node so that we can fill in the actual datum during
852850
* the data input loop.
853-
*
854-
* XXX to prevent premature constant folding in parse_coerce,
855-
* pass in a NULL constant to start with. See the comments in
856-
* coerce_type; this should be changed someday to use some sort
857-
* of Param node instead of a Const.
858851
*/
859-
con = makeConst(attr[i]->atttypid,
860-
attr[i]->attlen,
861-
(Datum) 0,
862-
true, /* is null */
863-
attr[i]->attbyval);
852+
prm = makeNode(Param);
853+
prm->paramkind = PARAM_EXEC;
854+
prm->paramid = 0;
855+
prm->paramtype = attr[i]->atttypid;
864856

865-
node = coerce_type_constraints((Node *) con, attr[i]->atttypid,
857+
node = coerce_type_constraints((Node *) prm, attr[i]->atttypid,
866858
COERCE_IMPLICIT_CAST);
867859

868860
/* check whether any constraints actually found */
869-
if (node != (Node *) con)
861+
if (node != (Node *) prm)
870862
{
871863
constraintexprs[i] = node;
872-
constraintconsts[i] = con;
873864
hasConstraints = true;
874865
}
875866
}
@@ -931,6 +922,11 @@ CopyFrom(Relation rel, List *attnumlist, bool binary, bool oids,
931922

932923
econtext = GetPerTupleExprContext(estate);
933924

925+
/* Make room for a PARAM_EXEC value for domain constraint checks */
926+
if (hasConstraints)
927+
econtext->ecxt_param_exec_vals = (ParamExecData *)
928+
palloc0(sizeof(ParamExecData));
929+
934930
while (!done)
935931
{
936932
bool skip_tuple;
@@ -1153,19 +1149,19 @@ CopyFrom(Relation rel, List *attnumlist, bool binary, bool oids,
11531149
*/
11541150
if (hasConstraints)
11551151
{
1152+
ParamExecData *prmdata = &econtext->ecxt_param_exec_vals[0];
1153+
11561154
for (i = 0; i < num_phys_attrs; i++)
11571155
{
11581156
Node *node = constraintexprs[i];
1159-
Const *con;
11601157
bool isnull;
11611158

11621159
if (node == NULL)
11631160
continue; /* no constraint for this attr */
11641161

1165-
/* Insert current row's value into the Const node */
1166-
con = constraintconsts[i];
1167-
con->constvalue = values[i];
1168-
con->constisnull = (nulls[i] == 'n');
1162+
/* Insert current row's value into the Param value */
1163+
prmdata->value = values[i];
1164+
prmdata->isnull = (nulls[i] == 'n');
11691165

11701166
/*
11711167
* Execute the constraint expression. Allow the expression

‎src/backend/executor/nodeSubplan.c

Lines changed: 19 additions & 12 deletions
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1994, Regents of the University of California
88
*
99
* IDENTIFICATION
10-
* $Header: /cvsroot/pgsql/src/backend/executor/nodeSubplan.c,v 1.33 2002/06/20 20:29:28 momjian Exp $
10+
* $Header: /cvsroot/pgsql/src/backend/executor/nodeSubplan.c,v 1.34 2002/11/26 03:01:57 tgl Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -150,37 +150,44 @@ ExecSubPlan(SubPlan *node, List *pvar, ExprContext *econtext, bool *isNull)
150150
foreach(lst, sublink->oper)
151151
{
152152
Expr *expr = (Expr *) lfirst(lst);
153-
Const *con = lsecond(expr->args);
153+
Param *prm = lsecond(expr->args);
154+
ParamExecData *prmdata;
154155
Datum expresult;
155156
bool expnull;
156157

157158
/*
158159
* The righthand side of the expression should be either a
159-
* Const or a function call or RelabelType node taking a Const
160+
* Param or a function call or RelabelType node taking a Param
160161
* as arg (these nodes represent run-time type coercions
161162
* inserted by the parser to get to the input type needed by
162-
* the operator). Find the Const node and insert the actual
163-
* righthand-side value into it.
163+
* the operator). Find the Param node and insert the actual
164+
* righthand-side value into the param's econtext slot.
165+
*
166+
* XXX possible improvement: could make a list of the ParamIDs
167+
* at startup time, instead of repeating this check at each row.
164168
*/
165-
if (!IsA(con, Const))
169+
if (!IsA(prm, Param))
166170
{
167-
switch (con->type)
171+
switch (nodeTag(prm))
168172
{
169173
case T_Expr:
170-
con = lfirst(((Expr *) con)->args);
174+
prm = lfirst(((Expr *) prm)->args);
171175
break;
172176
case T_RelabelType:
173-
con = (Const *) (((RelabelType *) con)->arg);
177+
prm = (Param *) (((RelabelType *) prm)->arg);
174178
break;
175179
default:
176180
/* will fail below */
177181
break;
178182
}
179-
if (!IsA(con, Const))
183+
if (!IsA(prm, Param))
180184
elog(ERROR, "ExecSubPlan: failed to find placeholder for subplan result");
181185
}
182-
con->constvalue = heap_getattr(tup, col, tdesc,
183-
&(con->constisnull));
186+
Assert(prm->paramkind == PARAM_EXEC);
187+
prmdata = &(econtext->ecxt_param_exec_vals[prm->paramid]);
188+
Assert(prmdata->execPlan == NULL);
189+
prmdata->value = heap_getattr(tup, col, tdesc,
190+
&(prmdata->isnull));
184191

185192
/*
186193
* Now we can eval the combining operator for this column.

‎src/backend/optimizer/plan/planner.c

Lines changed: 1 addition & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.130 2002/11/21 00:42:19 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.131 2002/11/26 03:01:58 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -720,8 +720,6 @@ preprocess_expression(Query *parse, Node *expr, int kind)
720720
*
721721
* Note that at this point quals have not yet been converted to
722722
* implicit-AND form, so we can apply eval_const_expressions directly.
723-
* Also note that we need to do this before SS_process_sublinks,
724-
* because that routine inserts bogus "Const" nodes.
725723
*/
726724
expr = eval_const_expressions(expr);
727725

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