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apache / hawq / bd6196f487c8028f3eca0f56509fe9d718ee31c6 / . / src / backend / parser / parse_expr.c
blob: eab56785a262c8b4de21b89c42191c9e244ecdc6 [file] [log] [blame]
/*-------------------------------------------------------------------------
*
* parse_expr.c
* handle expressions in parser
*
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.198 2006/10/04 00:29:55 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "catalog/namespace.h"
#include "catalog/pg_type.h"
#include "commands/dbcommands.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/plannodes.h"
#include "optimizer/clauses.h"
#include "optimizer/var.h"
#include "parser/analyze.h"
#include "parser/gramparse.h"
#include "parser/parse_agg.h"
#include "parser/parse_coerce.h"
#include "parser/parse_clause.h"
#include "parser/parse_expr.h"
#include "parser/parse_func.h"
#include "parser/parse_oper.h"
#include "parser/parse_relation.h"
#include "parser/parse_target.h"
#include "parser/parse_type.h"
#include "rewrite/rewriteManip.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
bool Transform_null_equals = false;
static Node *transformParamRef(ParseState *pstate, ParamRef *pref);
static Node *transformAExprOp(ParseState *pstate, A_Expr *a);
static Node *transformAExprAnd(ParseState *pstate, A_Expr *a);
static Node *transformAExprOr(ParseState *pstate, A_Expr *a);
static Node *transformAExprNot(ParseState *pstate, A_Expr *a);
static Node *transformAExprOpAny(ParseState *pstate, A_Expr *a);
static Node *transformAExprOpAll(ParseState *pstate, A_Expr *a);
static Node *transformAExprDistinct(ParseState *pstate, A_Expr *a);
static Node *transformAExprNullIf(ParseState *pstate, A_Expr *a);
static Node *transformAExprOf(ParseState *pstate, A_Expr *a);
static Node *transformAExprIn(ParseState *pstate, A_Expr *a);
static Node *transformFuncCall(ParseState *pstate, FuncCall *fn);
static Node *transformSubLink(ParseState *pstate, SubLink *sublink);
static Node *transformArrayExpr(ParseState *pstate, ArrayExpr *a);
static Node *transformRowExpr(ParseState *pstate, RowExpr *r);
static Node *transformTableValueExpr(ParseState *pstate, TableValueExpr *t);
static Node *transformCoalesceExpr(ParseState *pstate, CoalesceExpr *c);
static Node *transformMinMaxExpr(ParseState *pstate, MinMaxExpr *m);
static Node *transformBooleanTest(ParseState *pstate, BooleanTest *b);
static Node *transformColumnRef(ParseState *pstate, ColumnRef *cref);
static Node *transformWholeRowRef(ParseState *pstate, char *catalogname, char *schemaname,
char *relname, int location);
static Node *transformBooleanTest(ParseState *pstate, BooleanTest *b);
static Node *transformIndirection(ParseState *pstate, Node *basenode,
List *indirection);
static Node *transformGroupingFunc(ParseState *pstate, GroupingFunc *gf);
static Node *transformPercentileExpr(ParseState *pstate, PercentileExpr *p);
static Node *typecast_expression(ParseState *pstate, Node *expr,
TypeName *typname);
static Node *make_row_comparison_op(ParseState *pstate, List *opname,
List *largs, List *rargs, int location);
static Node *make_row_distinct_op(ParseState *pstate, List *opname,
RowExpr *lrow, RowExpr *rrow, int location);
static Expr *make_distinct_op(ParseState *pstate, List *opname,
Node *ltree, Node *rtree, int location);
static bool isWhenIsNotDistinctFromExpr(Node *warg);
static char *percentileFuncString(PercentileExpr *p, Oid *argtypes, int arglen,
Oid *sorttypes, int sortlen);
/*
* transformExpr -
* Analyze and transform expressions. Type checking and type casting is
* done here. The optimizer and the executor cannot handle the original
* (raw) expressions collected by the parse tree. Hence the transformation
* here.
*
* NOTE: there are various cases in which this routine will get applied to
* an already-transformed expression. Some examples:
* 1. At least one construct (BETWEEN/AND) puts the same nodes
* into two branches of the parse tree; hence, some nodes
* are transformed twice.
* 2. Another way it can happen is that coercion of an operator or
* function argument to the required type (via coerce_type())
* can apply transformExpr to an already-transformed subexpression.
* An example here is "SELECT count(*) + 1.0 FROM table".
* While it might be possible to eliminate these cases, the path of
* least resistance so far has been to ensure that transformExpr() does
* no damage if applied to an already-transformed tree. This is pretty
* easy for cases where the transformation replaces one node type with
* another, such as A_Const => Const; we just do nothing when handed
* a Const. More care is needed for node types that are used as both
* input and output of transformExpr; see SubLink for example.
*
* CDB: On return, pstate->breadcrumb.node points to the original 'expr' node.
* This is intended to provide a default cursor location in case an error is
* reported during further processing of the result, such as conversion to a
* target type.
*/
Node *
transformExpr(ParseState *pstate, Node *expr)
{
Node *result;
ParseStateBreadCrumb savebreadcrumb;
if (expr == NULL)
return NULL;
/* Guard against stack overflow due to overly complex expressions */
check_stack_depth();
/* CDB: Drop a breadcrumb, then push location stack. Must pop before return! */
Assert(pstate);
pstate->p_breadcrumb.node = (Node *)expr;
savebreadcrumb = pstate->p_breadcrumb;
pstate->p_breadcrumb.pop = &savebreadcrumb;
result = NULL;
switch (nodeTag(expr))
{
case T_ColumnRef:
result = transformColumnRef(pstate, (ColumnRef *) expr);
break;
case T_ParamRef:
result = transformParamRef(pstate, (ParamRef *) expr);
break;
case T_A_Const:
{
A_Const *con = (A_Const *) expr;
Value *val = &con->val;
result = (Node *) make_const(pstate, val, -1);
if (con->typname != NULL)
result = typecast_expression(pstate, result,
con->typname);
break;
}
case T_A_Indirection:
{
A_Indirection *ind = (A_Indirection *) expr;
result = transformExpr(pstate, ind->arg);
result = transformIndirection(pstate, result,
ind->indirection);
break;
}
case T_TypeCast:
{
TypeCast *tc = (TypeCast *) expr;
Node *arg = transformExpr(pstate, tc->arg);
result = typecast_expression(pstate, arg, tc->typname);
break;
}
case T_A_Expr:
{
A_Expr *a = (A_Expr *) expr;
switch (a->kind)
{
case AEXPR_OP:
result = transformAExprOp(pstate, a);
break;
case AEXPR_AND:
result = transformAExprAnd(pstate, a);
break;
case AEXPR_OR:
result = transformAExprOr(pstate, a);
break;
case AEXPR_NOT:
result = transformAExprNot(pstate, a);
break;
case AEXPR_OP_ANY:
result = transformAExprOpAny(pstate, a);
break;
case AEXPR_OP_ALL:
result = transformAExprOpAll(pstate, a);
break;
case AEXPR_DISTINCT:
result = transformAExprDistinct(pstate, a);
break;
case AEXPR_NULLIF:
result = transformAExprNullIf(pstate, a);
break;
case AEXPR_OF:
result = transformAExprOf(pstate, a);
break;
case AEXPR_IN:
result = transformAExprIn(pstate, a);
break;
default:
elog(ERROR, "unrecognized A_Expr kind: %d", a->kind);
}
break;
}
case T_FuncCall:
result = transformFuncCall(pstate, (FuncCall *) expr);
break;
case T_SubLink:
result = transformSubLink(pstate, (SubLink *) expr);
break;
case T_CaseExpr:
result = transformCaseExpr(pstate, (CaseExpr *) expr);
break;
case T_ArrayExpr:
result = transformArrayExpr(pstate, (ArrayExpr *) expr);
break;
case T_RowExpr:
result = transformRowExpr(pstate, (RowExpr *) expr);
break;
case T_TableValueExpr:
result = transformTableValueExpr(pstate, (TableValueExpr *) expr);
break;
case T_CoalesceExpr:
result = transformCoalesceExpr(pstate, (CoalesceExpr *) expr);
break;
case T_MinMaxExpr:
result = transformMinMaxExpr(pstate, (MinMaxExpr *) expr);
break;
case T_NullTest:
{
NullTest *n = (NullTest *) expr;
n->arg = (Expr *) transformExpr(pstate, (Node *) n->arg);
/* the argument can be any type, so don't coerce it */
result = expr;
break;
}
case T_BooleanTest:
result = transformBooleanTest(pstate, (BooleanTest *) expr);
break;
case T_CurrentOfExpr:
{
/*
* The target RTE must be simply updatable. If not, we error out
* early here to avoid having to deal with error cases later:
* rewriting/planning against views, for example.
*/
Assert(pstate->p_target_rangetblentry != NULL);
if (!isSimplyUpdatableRelation(pstate->p_target_rangetblentry->relid))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("\"%s\" is not simply updatable",
pstate->p_target_relation->rd_rel->relname.data)));
CurrentOfExpr *c = (CurrentOfExpr *) expr;
int sublevels_up;
c->cvarno = RTERangeTablePosn(pstate,
pstate->p_target_rangetblentry,
&sublevels_up);
c->target_relid = pstate->p_target_rangetblentry->relid;
Assert(sublevels_up == 0);
result = expr;
break;
}
case T_GroupingFunc:
{
GroupingFunc *gf = (GroupingFunc *)expr;
result = transformGroupingFunc(pstate, gf);
break;
}
case T_PartitionBoundSpec:
{
PartitionBoundSpec *in = (PartitionBoundSpec *)expr;
PartitionRangeItem *ri;
List *out = NIL;
ListCell *lc;
if (in->partStart)
{
ri = (PartitionRangeItem *)in->partStart;
/* ALTER TABLE ... ADD PARTITION might feed
* "pre-cooked" expressions into the boundspec for
* range items (which are Lists)
*/
{
Assert(IsA(in->partStart, PartitionRangeItem));
foreach(lc, ri->partRangeVal)
{
Node *n = lfirst(lc);
out = lappend(out, transformExpr(pstate, n));
}
ri->partRangeVal = out;
out = NIL;
}
}
if (in->partEnd)
{
ri = (PartitionRangeItem *)in->partEnd;
/* ALTER TABLE ... ADD PARTITION might feed
* "pre-cooked" expressions into the boundspec for
* range items (which are Lists)
*/
{
Assert(IsA(in->partEnd, PartitionRangeItem));
foreach(lc, ri->partRangeVal)
{
Node *n = lfirst(lc);
out = lappend(out, transformExpr(pstate, n));
}
ri->partRangeVal = out;
out = NIL;
}
}
if (in->partEvery)
{
ri = (PartitionRangeItem *)in->partEvery;
Assert(IsA(in->partEvery, PartitionRangeItem));
foreach(lc, ri->partRangeVal)
{
Node *n = lfirst(lc);
out = lappend(out, transformExpr(pstate, n));
}
ri->partRangeVal = out;
}
result = (Node *)in;
}
break;
case T_PercentileExpr:
result = transformPercentileExpr(pstate, (PercentileExpr *) expr);
break;
/*********************************************
* Quietly accept node types that may be presented when we are
* called on an already-transformed tree.
*
* Do any other node types need to be accepted? For now we are
* taking a conservative approach, and only accepting node
* types that are demonstrably necessary to accept.
*********************************************/
case T_Var:
case T_Const:
case T_Param:
case T_Aggref:
case T_ArrayRef:
case T_FuncExpr:
case T_OpExpr:
case T_DistinctExpr:
case T_ScalarArrayOpExpr:
case T_NullIfExpr:
case T_BoolExpr:
case T_FieldSelect:
case T_FieldStore:
case T_RelabelType:
case T_ConvertRowtypeExpr:
case T_CaseTestExpr:
case T_CoerceToDomain:
case T_CoerceToDomainValue:
case T_SetToDefault:
case T_GroupId:
case T_Integer:
{
result = (Node *) expr;
break;
}
default:
/* should not reach here */
elog(ERROR, "unrecognized node type: %d", (int) nodeTag(expr));
break;
}
/* CDB: Pop error location stack, leaving breadcrumb on our input expr. */
Assert(pstate->p_breadcrumb.pop == &savebreadcrumb);
pstate->p_breadcrumb = savebreadcrumb;
return result;
}
/*
* parse_expr_location
*
* Looks for a node with a 'location' field in the given parse tree expression.
* Returns the location (the byte offset of a token within the source string),
* or -1 if unknown.
*
* NB: For best results, expr should be an untransformed expression, because
* after transformExpr() most nodes have no 'location' field.
*/
int
parse_expr_location(Expr *expr)
{
int loc;
ListCell *cell;
if (expr == NULL)
return -1;
switch (nodeTag(expr))
{
case T_ColumnRef:
loc = ((ColumnRef *)expr)->location;
break;
case T_ParamRef:
loc = ((ParamRef *)expr)->location;
break;
case T_A_Const:
loc = ((A_Const *)expr)->location;
break;
case T_A_Indirection:
{
A_Indirection *ind = (A_Indirection *)expr;
loc = parse_expr_location((Expr *)ind->arg);
if (loc < 0)
loc = parse_expr_location((Expr *)ind->indirection);
break;
}
case T_TypeCast:
{
TypeCast *typecast = (TypeCast *)expr;
loc = parse_expr_location((Expr *)typecast->arg);
if (loc < 0)
loc = parse_expr_location((Expr *)typecast->typname);
break;
}
case T_A_Expr:
loc = ((A_Expr *)expr)->location;
break;
case T_FuncCall:
loc = ((FuncCall *)expr)->location;
break;
case T_SubLink:
loc = ((SubLink *)expr)->location;
break;
case T_CaseExpr:
{
CaseExpr *caseexpr = (CaseExpr *)expr;
CaseWhen *casewhen;
loc = parse_expr_location(caseexpr->arg);
foreach(cell, caseexpr->args)
{
if (loc >= 0)
break;
casewhen = (CaseWhen *)lfirst(cell);
loc = parse_expr_location(casewhen->expr);
if (loc < 0)
loc = parse_expr_location(casewhen->result);
}
if (loc < 0)
loc = parse_expr_location(caseexpr->defresult);
break;
}
case T_ArrayExpr:
loc = parse_expr_location((Expr *)((ArrayExpr *)expr)->elements);
break;
case T_RowExpr:
loc = parse_expr_location((Expr *)((RowExpr *)expr)->args);
break;
case T_CoalesceExpr:
loc = parse_expr_location((Expr *)((CoalesceExpr *)expr)->args);
break;
case T_MinMaxExpr:
loc = parse_expr_location((Expr *)((MinMaxExpr *)expr)->args);
break;
case T_NullTest:
loc = parse_expr_location(((NullTest *)expr)->arg);
break;
case T_BooleanTest:
loc = parse_expr_location(((BooleanTest *)expr)->arg);
break;
case T_GroupingFunc:
loc = parse_expr_location((Expr *)((GroupingFunc *)expr)->args);
break;
/* Above nodes taken from transformExpr(). Additional nodes below. */
case T_JoinExpr:
loc = parse_expr_location((Expr *)((JoinExpr *)expr)->rarg);
break;
case T_List:
loc = -1;
foreach(cell, (List *)expr)
{
loc = parse_expr_location((Expr *)lfirst(cell));
if (loc >= 0)
break;
}
break;
case T_RangeFunction:
loc = parse_expr_location((Expr *)((RangeFunction *)expr)->funccallnode);
break;
case T_RangeSubselect:
loc = parse_expr_location((Expr *)((RangeSubselect *)expr)->subquery);
break;
case T_RangeVar:
loc = ((RangeVar *)expr)->location;
break;
case T_ResTarget:
loc = ((ResTarget *)expr)->location;
break;
case T_SelectStmt:
{
SelectStmt *ss = (SelectStmt *)expr;
if (ss->larg)
loc = parse_expr_location((Expr *)ss->larg); /* set op */
else if (ss->valuesLists)
loc = parse_expr_location((Expr *)ss->valuesLists); /* VALUES */
else
loc = parse_expr_location((Expr *)ss->targetList); /* SELECT */
break;
}
case T_TypeName:
loc = ((TypeName *)expr)->location;
break;
case T_WindowSpec:
loc = ((WindowSpec *)expr)->location;
break;
case T_PercentileExpr:
loc = ((PercentileExpr *) expr)->location;
break;
default:
loc = -1;
}
return loc;
} /* parse_expr_location */
static Node *
transformIndirection(ParseState *pstate, Node *basenode, List *indirection)
{
Node *result = basenode;
List *subscripts = NIL;
ListCell *i;
ParseStateBreadCrumb savebreadcrumb;
/* CDB: Push error location stack. Must pop before return! */
Assert(pstate);
savebreadcrumb = pstate->p_breadcrumb;
pstate->p_breadcrumb.pop = &savebreadcrumb;
/*
* We have to split any field-selection operations apart from
* subscripting. Adjacent A_Indices nodes have to be treated as a single
* multidimensional subscript operation.
*/
foreach(i, indirection)
{
Node *n = lfirst(i);
if (IsA(n, A_Indices))
subscripts = lappend(subscripts, n);
else
{
Assert(IsA(n, String));
/* process subscripts before this field selection */
if (subscripts)
result = (Node *) transformArraySubscripts(pstate,
result,
exprType(result),
InvalidOid,
-1,
subscripts,
NULL);
subscripts = NIL;
result = ParseFuncOrColumn(pstate,
list_make1(n),
list_make1(result),
NIL, false, false, true,
NULL, -1, NULL);
}
}
/* process trailing subscripts, if any */
if (subscripts)
result = (Node *) transformArraySubscripts(pstate,
result,
exprType(result),
InvalidOid,
-1,
subscripts,
NULL);
/* CDB: Pop error location stack. */
Assert(pstate->p_breadcrumb.pop == &savebreadcrumb);
pstate->p_breadcrumb = savebreadcrumb;
return result;
}
static Node *
transformColumnRef(ParseState *pstate, ColumnRef *cref)
{
int numnames = list_length(cref->fields);
Node *node;
int levels_up;
ParseStateBreadCrumb savebreadcrumb;
/* CDB: Push error location stack. Must pop before return! */
Assert(pstate);
savebreadcrumb = pstate->p_breadcrumb;
pstate->p_breadcrumb.pop = &savebreadcrumb;
pstate->p_breadcrumb.node = (Node *)cref;
/*----------
* The allowed syntaxes are:
*
* A First try to resolve as unqualified column name;
* if no luck, try to resolve as unqualified table name (A.*).
* A.B A is an unqualified table name; B is either a
* column or function name (trying column name first).
* A.B.C schema A, table B, col or func name C.
* A.B.C.D catalog A, schema B, table C, col or func D.
* A.* A is an unqualified table name; means whole-row value.
* A.B.* whole-row value of table B in schema A.
* A.B.C.* whole-row value of table C in schema B in catalog A.
*
* We do not need to cope with bare "*"; that will only be accepted by
* the grammar at the top level of a SELECT list, and transformTargetList
* will take care of it before it ever gets here. Also, "A.*" etc will
* be expanded by transformTargetList if they appear at SELECT top level,
* so here we are only going to see them as function or operator inputs.
*
* Currently, if a catalog name is given then it must equal the current
* database name; we check it here and then discard it.
*----------
*/
switch (numnames)
{
case 1:
{
char *name = strVal(linitial(cref->fields));
/* Try to identify as an unqualified column */
node = colNameToVar(pstate, name, false, cref->location);
if (node == NULL)
{
/*
* Not known as a column of any range-table entry.
*
* Consider the possibility that it's VALUE in a domain
* check expression. (We handle VALUE as a name, not a
* keyword, to avoid breaking a lot of applications that
* have used VALUE as a column name in the past.)
*/
if (pstate->p_value_substitute != NULL &&
strcmp(name, "value") == 0)
{
node = (Node *) copyObject(pstate->p_value_substitute);
break;
}
/*
* Try to find the name as a relation. Note that only
* relations already entered into the rangetable will be
* recognized.
*
* This is a hack for backwards compatibility with
* PostQUEL-inspired syntax. The preferred form now is
* "rel.*".
*/
if (refnameRangeTblEntry(pstate, NULL /*catalogname*/, NULL /*schemaname*/, name, cref->location,
&levels_up) != NULL)
node = transformWholeRowRef(pstate, NULL /*catalogname*/, NULL, name,
cref->location);
else
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" does not exist",
name),
errOmitLocation(true),
parser_errposition(pstate, cref->location)));
}
break;
}
case 2:
{
char *name1 = strVal(linitial(cref->fields));
char *name2 = strVal(lsecond(cref->fields));
/* Whole-row reference? */
if (strcmp(name2, "*") == 0)
{
node = transformWholeRowRef(pstate, NULL /*catalogname*/, NULL /*schemaname*/, name1,
cref->location);
break;
}
/* Try to identify as a once-qualified column */
node = qualifiedNameToVar(pstate, NULL /*catalogname*/, NULL /*schemaname*/, name1, name2, true,
cref->location);
if (node == NULL)
{
/*
* Not known as a column of any range-table entry, so try
* it as a function call. Here, we will create an
* implicit RTE for tables not already entered.
*/
node = transformWholeRowRef(pstate, NULL /*catalogname*/, NULL, name1,
cref->location);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(name2)),
list_make1(node),
NIL, false, false, true, NULL,
cref->location, NULL);
}
break;
}
case 3:
{
char *name1 = strVal(linitial(cref->fields));
char *name2 = strVal(lsecond(cref->fields));
char *name3 = strVal(lthird(cref->fields));
/* Whole-row reference? */
if (strcmp(name3, "*") == 0)
{
node = transformWholeRowRef(pstate, NULL /*catalogname*/, name1, name2,
cref->location);
break;
}
/* Try to identify as a twice-qualified column */
node = qualifiedNameToVar(pstate, NULL /*catalogname*/, name1, name2, name3, true,
cref->location);
if (node == NULL)
{
/* Try it as a function call */
node = transformWholeRowRef(pstate, NULL /*catalogname*/, name1, name2,
cref->location);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(name3)),
list_make1(node),
NIL, false, false, true, NULL,
cref->location, NULL);
}
break;
}
case 4:
{
char *name1 = strVal(linitial(cref->fields));
char *name2 = strVal(lsecond(cref->fields));
char *name3 = strVal(lthird(cref->fields));
char *name4 = strVal(lfourth(cref->fields));
/* Whole-row reference? */
if (strcmp(name4, "*") == 0)
{
node = transformWholeRowRef(pstate, name1, name2, name3,
cref->location);
break;
}
/* Try to identify as a twice-qualified column */
node = qualifiedNameToVar(pstate, name1, name2, name3, name4, true,
cref->location);
if (node == NULL)
{
/* Try it as a function call */
node = transformWholeRowRef(pstate, name1, name2, name3,
cref->location);
node = ParseFuncOrColumn(pstate,
list_make1(makeString(name4)),
list_make1(node),
NIL, false, false, true, NULL,
cref->location, NULL);
}
break;
}
default:
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("improper qualified name (too many dotted names): %s",
NameListToString(cref->fields)),
parser_errposition(pstate, cref->location)));
node = NULL; /* keep compiler quiet */
break;
}
/* CDB: Pop error location stack. */
Assert(pstate->p_breadcrumb.pop == &savebreadcrumb);
pstate->p_breadcrumb = savebreadcrumb;
return node;
}
static Node *
transformParamRef(ParseState *pstate, ParamRef *pref)
{
int paramno = pref->number;
ParseState *toppstate;
Param *param;
/*
* Find topmost ParseState, which is where paramtype info lives.
*/
toppstate = pstate;
while (toppstate->parentParseState != NULL)
toppstate = toppstate->parentParseState;
/* Check parameter number is in range */
if (paramno <= 0) /* probably can't happen? */
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_PARAMETER),
errmsg("there is no parameter $%d", paramno)));
if (paramno > toppstate->p_numparams)
{
if (!toppstate->p_variableparams)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_PARAMETER),
errmsg("there is no parameter $%d",
paramno),
errOmitLocation(true)));
/* Okay to enlarge param array */
if (toppstate->p_paramtypes)
toppstate->p_paramtypes =
(Oid *) repalloc(toppstate->p_paramtypes,
paramno * sizeof(Oid));
else
toppstate->p_paramtypes =
(Oid *) palloc(paramno * sizeof(Oid));
/* Zero out the previously-unreferenced slots */
MemSet(toppstate->p_paramtypes + toppstate->p_numparams,
0,
(paramno - toppstate->p_numparams) * sizeof(Oid));
toppstate->p_numparams = paramno;
}
if (toppstate->p_variableparams)
{
/* If not seen before, initialize to UNKNOWN type */
if (toppstate->p_paramtypes[paramno - 1] == InvalidOid)
toppstate->p_paramtypes[paramno - 1] = UNKNOWNOID;
}
param = makeNode(Param);
param->paramkind = PARAM_EXTERN;
param->paramid = paramno;
param->paramtype = toppstate->p_paramtypes[paramno - 1];
return (Node *) param;
}
static Node *
transformAExprOp(ParseState *pstate, A_Expr *a)
{
Node *lexpr = a->lexpr;
Node *rexpr = a->rexpr;
Node *result;
/*
* Special-case "foo = NULL" and "NULL = foo" for compatibility with
* standards-broken products (like Microsoft's). Turn these into IS NULL
* exprs.
*/
if (Transform_null_equals &&
list_length(a->name) == 1 &&
strcmp(strVal(linitial(a->name)), "=") == 0 &&
(exprIsNullConstant(lexpr) || exprIsNullConstant(rexpr)))
{
NullTest *n = makeNode(NullTest);
n->nulltesttype = IS_NULL;
if (exprIsNullConstant(lexpr))
n->arg = (Expr *) rexpr;
else
n->arg = (Expr *) lexpr;
result = transformExpr(pstate, (Node *) n);
}
else if (lexpr && IsA(lexpr, RowExpr) &&
rexpr && IsA(rexpr, SubLink) &&
((SubLink *) rexpr)->subLinkType == EXPR_SUBLINK)
{
/*
* Convert "row op subselect" into a ROWCOMPARE sublink. Formerly the
* grammar did this, but now that a row construct is allowed anywhere
* in expressions, it's easier to do it here.
*/
SubLink *s = (SubLink *) rexpr;
s->subLinkType = ROWCOMPARE_SUBLINK;
s->testexpr = lexpr;
s->operName = a->name;
result = transformExpr(pstate, (Node *) s);
}
else if (lexpr && IsA(lexpr, RowExpr) &&
rexpr && IsA(rexpr, RowExpr))
{
/* "row op row" */
lexpr = transformExpr(pstate, lexpr);
rexpr = transformExpr(pstate, rexpr);
Assert(IsA(lexpr, RowExpr));
Assert(IsA(rexpr, RowExpr));
/* CDB: Drop a breadcrumb in case of error. */
pstate->p_breadcrumb.node = (Node *)a;
result = make_row_comparison_op(pstate,
a->name,
((RowExpr *) lexpr)->args,
((RowExpr *) rexpr)->args,
a->location);
}
else
{
/* Ordinary scalar operator */
lexpr = transformExpr(pstate, lexpr);
rexpr = transformExpr(pstate, rexpr);
/* CDB: Drop a breadcrumb in case of error. */
pstate->p_breadcrumb.node = (Node *)a;
result = (Node *) make_op(pstate,
a->name,
lexpr,
rexpr,
a->location);
}
return result;
}
static Node *
transformAExprAnd(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExpr(pstate, a->lexpr);
Node *rexpr = transformExpr(pstate, a->rexpr);
lexpr = coerce_to_boolean(pstate, lexpr, "AND");
rexpr = coerce_to_boolean(pstate, rexpr, "AND");
return (Node *) makeBoolExpr(AND_EXPR,
list_make2(lexpr, rexpr), a->location);
}
static Node *
transformAExprOr(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExpr(pstate, a->lexpr);
Node *rexpr = transformExpr(pstate, a->rexpr);
lexpr = coerce_to_boolean(pstate, lexpr, "OR");
rexpr = coerce_to_boolean(pstate, rexpr, "OR");
return (Node *) makeBoolExpr(OR_EXPR,
list_make2(lexpr, rexpr), a->location);
}
static Node *
transformAExprNot(ParseState *pstate, A_Expr *a)
{
Node *rexpr = transformExpr(pstate, a->rexpr);
rexpr = coerce_to_boolean(pstate, rexpr, "NOT");
return (Node *) makeBoolExpr(NOT_EXPR,
list_make1(rexpr), a->location);
}
static Node *
transformAExprOpAny(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExpr(pstate, a->lexpr);
Node *rexpr = transformExpr(pstate, a->rexpr);
return (Node *) make_scalar_array_op(pstate,
a->name,
true,
lexpr,
rexpr,
a->location);
}
static Node *
transformAExprOpAll(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExpr(pstate, a->lexpr);
Node *rexpr = transformExpr(pstate, a->rexpr);
return (Node *) make_scalar_array_op(pstate,
a->name,
false,
lexpr,
rexpr,
a->location);
}
static Node *
transformAExprDistinct(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExpr(pstate, a->lexpr);
Node *rexpr = transformExpr(pstate, a->rexpr);
if (lexpr && IsA(lexpr, RowExpr) &&
rexpr && IsA(rexpr, RowExpr))
{
/* "row op row" */
return make_row_distinct_op(pstate, a->name,
(RowExpr *) lexpr,
(RowExpr *) rexpr,
a->location);
}
else
{
/* Ordinary scalar operator */
return (Node *) make_distinct_op(pstate,
a->name,
lexpr,
rexpr,
a->location);
}
}
static Node *
transformAExprNullIf(ParseState *pstate, A_Expr *a)
{
Node *lexpr = transformExpr(pstate, a->lexpr);
Node *rexpr = transformExpr(pstate, a->rexpr);
Node *result;
result = (Node *) make_op(pstate,
a->name,
lexpr,
rexpr,
a->location);
if (((OpExpr *) result)->opresulttype != BOOLOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("NULLIF requires = operator to yield boolean"),
parser_errposition(pstate, a->location)));
/*
* We rely on NullIfExpr and OpExpr being the same struct
*/
NodeSetTag(result, T_NullIfExpr);
return result;
}
static Node *
transformAExprOf(ParseState *pstate, A_Expr *a)
{
/*
* Checking an expression for match to a list of type names. Will result
* in a boolean constant node.
*/
Node *lexpr = transformExpr(pstate, a->lexpr);
ListCell *telem;
Oid ltype,
rtype;
bool matched = false;
ltype = exprType(lexpr);
foreach(telem, (List *) a->rexpr)
{
rtype = typenameTypeId(pstate, lfirst(telem));
matched = (rtype == ltype);
if (matched)
break;
}
/*
* We have two forms: equals or not equals. Flip the sense of the result
* for not equals.
*/
if (strcmp(strVal(linitial(a->name)), "<>") == 0)
matched = (!matched);
return makeBoolConst(matched, false);
}
static Node *
transformAExprIn(ParseState *pstate, A_Expr *a)
{
Node *lexpr;
List *rexprs;
List *typeids;
bool useOr;
bool haveRowExpr;
Node *result;
ListCell *l;
/*
* If the operator is <>, combine with AND not OR.
*/
if (strcmp(strVal(linitial(a->name)), "<>") == 0)
useOr = false;
else
useOr = true;
/*
* We try to generate a ScalarArrayOpExpr from IN/NOT IN, but this is only
* possible if the inputs are all scalars (no RowExprs) and there is a
* suitable array type available. If not, we fall back to a boolean
* condition tree with multiple copies of the lefthand expression.
*
* First step: transform all the inputs, and detect whether any are
* RowExprs.
*/
lexpr = transformExpr(pstate, a->lexpr);
haveRowExpr = (lexpr && IsA(lexpr, RowExpr));
typeids = list_make1_oid(exprType(lexpr));
rexprs = NIL;
foreach(l, (List *) a->rexpr)
{
Node *rexpr = transformExpr(pstate, lfirst(l));
haveRowExpr |= (rexpr && IsA(rexpr, RowExpr));
rexprs = lappend(rexprs, rexpr);
typeids = lappend_oid(typeids, exprType(rexpr));
}
/* CDB: Drop a breadcrumb in case of error. */
pstate->p_breadcrumb.node = (Node *)a;
/*
* If not forced by presence of RowExpr, try to resolve a common scalar
* type for all the expressions, and see if it has an array type. (But if
* there's only one righthand expression, we may as well just fall through
* and generate a simple = comparison.)
*/
if (!haveRowExpr && list_length(rexprs) != 1)
{
Oid scalar_type;
Oid array_type;
/*
* Select a common type for the array elements. Note that since the
* LHS' type is first in the list, it will be preferred when there is
* doubt (eg, when all the RHS items are unknown literals).
*/
scalar_type = select_common_type(typeids, "IN");
/* Do we have an array type to use? */
array_type = get_array_type(scalar_type);
if (array_type != InvalidOid)
{
/*
* OK: coerce all the right-hand inputs to the common type and
* build an ArrayExpr for them.
*/
List *aexprs;
ArrayExpr *newa;
aexprs = NIL;
foreach(l, rexprs)
{
Node *rexpr = (Node *) lfirst(l);
rexpr = coerce_to_common_type(pstate, rexpr,
scalar_type,
"IN");
aexprs = lappend(aexprs, rexpr);
}
newa = makeNode(ArrayExpr);
newa->array_typeid = array_type;
newa->element_typeid = scalar_type;
newa->elements = aexprs;
newa->multidims = false;
return (Node *) make_scalar_array_op(pstate,
a->name,
useOr,
lexpr,
(Node *) newa,
a->location);
}
}
/*
* Must do it the hard way, ie, with a boolean expression tree.
*/
result = NULL;
foreach(l, rexprs)
{
Node *rexpr = (Node *) lfirst(l);
Node *cmp;
if (haveRowExpr)
{
if (!IsA(lexpr, RowExpr) ||
!IsA(rexpr, RowExpr))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("arguments of row IN must all be row expressions"),
parser_errposition(pstate, a->location)));
cmp = make_row_comparison_op(pstate,
a->name,
(List *) copyObject(((RowExpr *) lexpr)->args),
((RowExpr *) rexpr)->args,
a->location);
}
else
cmp = (Node *) make_op(pstate,
a->name,
copyObject(lexpr),
rexpr,
a->location);
cmp = coerce_to_boolean(pstate, cmp, "IN");
if (result == NULL)
result = cmp;
else
result = (Node *) makeBoolExpr(useOr ? OR_EXPR : AND_EXPR,
list_make2(result, cmp), a->location);
}
return result;
}
static Node *
transformFuncCall(ParseState *pstate, FuncCall *fn)
{
List *targs;
ListCell *args;
/*
* Transform the list of arguments. We use a shallow list copy and then
* transform-in-place to avoid O(N^2) behavior from repeated lappend's.
*
* XXX: repeated lappend() would no longer result in O(n^2) behavior;
* worth reconsidering this design?
*/
targs = list_copy(fn->args);
foreach(args, targs)
{
lfirst(args) = transformExpr(pstate,
(Node *) lfirst(args));
}
/* CDB: Drop a breadcrumb in case of error. */
pstate->p_breadcrumb.node = (Node *)fn;
return ParseFuncOrColumn(pstate,
fn->funcname,
targs,
fn->agg_order,
fn->agg_star,
fn->agg_distinct,
false,
(WindowSpec *)fn->over,
fn->location,
fn->agg_filter);
}
/*
* Check if this is CASE x WHEN IS NOT DISTINCT FROM y:
* From the raw grammar output, we produce AEXPR_NOT expression
* which has the rhs = AEXPR_DISTINCT expression which has its lhs = NULL
*/
static bool
isWhenIsNotDistinctFromExpr(Node *warg)
{
if (IsA(warg, A_Expr))
{
A_Expr *top = (A_Expr *) warg;
if (top->kind == AEXPR_NOT && IsA(top->rexpr, A_Expr))
{
A_Expr *expr = (A_Expr *) top->rexpr;
if (expr->kind == AEXPR_DISTINCT && expr->lexpr == NULL)
return true;
}
}
return false;
}
Node *
transformCaseExpr(ParseState *pstate, CaseExpr *c)
{
CaseExpr *newc;
Node *arg;
CaseTestExpr *placeholder;
List *newargs;
List *typeids;
ListCell *l;
Node *defresult;
Oid ptype;
/* If we already transformed this node, do nothing */
if (OidIsValid(c->casetype))
return (Node *) c;
newc = makeNode(CaseExpr);
/* transform the test expression, if any */
arg = transformExpr(pstate, (Node *) c->arg);
/* generate placeholder for test expression */
if (arg)
{
/*
* If test expression is an untyped literal, force it to text. We have
* to do something now because we won't be able to do this coercion on
* the placeholder. This is not as flexible as what was done in 7.4
* and before, but it's good enough to handle the sort of silly coding
* commonly seen.
*/
if (exprType(arg) == UNKNOWNOID)
arg = coerce_to_common_type(pstate, arg, TEXTOID, "CASE");
placeholder = makeNode(CaseTestExpr);
placeholder->typeId = exprType(arg);
placeholder->typeMod = exprTypmod(arg);
}
else
placeholder = NULL;
newc->arg = (Expr *) arg;
/* transform the list of arguments */
newargs = NIL;
typeids = NIL;
foreach(l, c->args)
{
CaseWhen *w = (CaseWhen *) lfirst(l);
CaseWhen *neww = makeNode(CaseWhen);
Node *warg;
Assert(IsA(w, CaseWhen));
warg = (Node *) w->expr;
if (placeholder)
{
/*
* CASE placeholder WHEN IS NOT DISTINCT FROM warg:
* set: warg->rhs->lhs = placeholder
*/
if (isWhenIsNotDistinctFromExpr(warg))
{
/*
* Make a copy before we change warg.
* In transformation we don't want to change source (CaseExpr* Node).
* Always create new node and do the transformation
*/
warg = copyObject(warg);
A_Expr *top = (A_Expr *) warg;
A_Expr *expr = (A_Expr *) top->rexpr;
expr->lexpr = (Node *) placeholder;
}
else
warg = (Node *) makeSimpleA_Expr(AEXPR_OP, "=",
(Node *) placeholder,
warg,
-1);
}
else
{
if (isWhenIsNotDistinctFromExpr(warg))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("syntax error at or near \"NOT\""),
errhint("Missing <operand> for \"CASE <operand> WHEN IS NOT DISTINCT FROM ...\"")));
}
neww->expr = (Expr *) transformExpr(pstate, warg);
neww->expr = (Expr *) coerce_to_boolean(pstate,
(Node *) neww->expr,
"CASE/WHEN");
warg = (Node *) w->result;
neww->result = (Expr *) transformExpr(pstate, warg);
newargs = lappend(newargs, neww);
typeids = lappend_oid(typeids, exprType((Node *) neww->result));
}
newc->args = newargs;
/* transform the default clause */
defresult = (Node *) c->defresult;
if (defresult == NULL)
{
A_Const *n = makeNode(A_Const);
n->val.type = T_Null;
defresult = (Node *) n;
}
newc->defresult = (Expr *) transformExpr(pstate, defresult);
/*
* Note: default result is considered the most significant type in
* determining preferred type. This is how the code worked before, but it
* seems a little bogus to me --- tgl
*/
typeids = lcons_oid(exprType((Node *) newc->defresult), typeids);
/* CDB: Drop a breadcrumb in case of error. */
pstate->p_breadcrumb.node = (Node *)c;
ptype = select_common_type(typeids, "CASE");
Assert(OidIsValid(ptype));
newc->casetype = ptype;
/* Convert default result clause, if necessary */
newc->defresult = (Expr *)
coerce_to_common_type(pstate,
(Node *) newc->defresult,
ptype,
"CASE/ELSE");
/* Convert when-clause results, if necessary */
foreach(l, newc->args)
{
CaseWhen *w = (CaseWhen *) lfirst(l);
w->result = (Expr *)
coerce_to_common_type(pstate,
(Node *) w->result,
ptype,
"CASE/WHEN");
}
return (Node *) newc;
}
static Node *
transformSubLink(ParseState *pstate, SubLink *sublink)
{
List *qtrees;
Query *qtree;
Node *result = (Node *) sublink;
/* If we already transformed this node, do nothing */
if (IsA(sublink->subselect, Query))
return result;
pstate->p_hasSubLinks = true;
qtrees = parse_sub_analyze(sublink->subselect, pstate);
/*
* Check that we got something reasonable. Many of these conditions are
* impossible given restrictions of the grammar, but check 'em anyway.
*/
Insist(list_length(qtrees) == 1);
qtree = (Query *) linitial(qtrees);
if (!IsA(qtree, Query) ||
qtree->commandType != CMD_SELECT ||
qtree->utilityStmt != NULL)
elog(ERROR, "unexpected non-SELECT command in SubLink");
if (qtree->intoClause)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery cannot have SELECT INTO"),
errOmitLocation(true)));
sublink->subselect = (Node *) qtree;
if (sublink->subLinkType == EXISTS_SUBLINK)
{
/*
* EXISTS needs no test expression or combining operator. These fields
* should be null already, but make sure.
*/
sublink->testexpr = NULL;
sublink->operName = NIL;
}
else if (sublink->subLinkType == EXPR_SUBLINK ||
sublink->subLinkType == ARRAY_SUBLINK)
{
ListCell *tlist_item = list_head(qtree->targetList);
/*
* Make sure the subselect delivers a single column (ignoring resjunk
* targets).
*/
if (tlist_item == NULL ||
((TargetEntry *) lfirst(tlist_item))->resjunk)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery must return a column")));
while ((tlist_item = lnext(tlist_item)) != NULL)
{
if (!((TargetEntry *) lfirst(tlist_item))->resjunk)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery must return only one column")));
}
/*
* EXPR and ARRAY need no test expression or combining operator. These
* fields should be null already, but make sure.
*/
sublink->testexpr = NULL;
sublink->operName = NIL;
}
else
{
/* ALL, ANY, or ROWCOMPARE: generate row-comparing expression */
Node *lefthand;
List *left_list;
List *right_list;
ListCell *l;
/*
* Transform lefthand expression, and convert to a list
*/
lefthand = transformExpr(pstate, sublink->testexpr);
if (lefthand && IsA(lefthand, RowExpr))
left_list = ((RowExpr *) lefthand)->args;
else
left_list = list_make1(lefthand);
/*
* Build a list of PARAM_SUBLINK nodes representing the output columns
* of the subquery.
*/
right_list = NIL;
foreach(l, qtree->targetList)
{
TargetEntry *tent = (TargetEntry *) lfirst(l);
Param *param;
if (tent->resjunk)
continue;
param = makeNode(Param);
param->paramkind = PARAM_SUBLINK;
param->paramid = tent->resno;
param->paramtype = exprType((Node *) tent->expr);
right_list = lappend(right_list, param);
}
/* CDB: Drop a breadcrumb in case of error. */
pstate->p_breadcrumb.node = (Node *)sublink;
/*
* We could rely on make_row_comparison_op to complain if the list
* lengths differ, but we prefer to generate a more specific error
* message.
*/
if (list_length(left_list) < list_length(right_list))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery has too many columns")));
if (list_length(left_list) > list_length(right_list))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery has too few columns")));
/*
* Identify the combining operator(s) and generate a suitable
* row-comparison expression.
*/
sublink->testexpr = make_row_comparison_op(pstate,
sublink->operName,
left_list,
right_list,
-1);
}
return result;
}
static Node *
transformArrayExpr(ParseState *pstate, ArrayExpr *a)
{
ArrayExpr *newa = makeNode(ArrayExpr);
List *newelems = NIL;
List *newcoercedelems = NIL;
List *typeids = NIL;
ListCell *element;
Oid array_type;
Oid element_type;
/* Transform the element expressions */
foreach(element, a->elements)
{
Node *e = (Node *) lfirst(element);
Node *newe;
newe = transformExpr(pstate, e);
newelems = lappend(newelems, newe);
typeids = lappend_oid(typeids, exprType(newe));
}
/* CDB: Drop a breadcrumb in case of error. */
pstate->p_breadcrumb.node = (Node *)a;
/* Select a common type for the elements */
element_type = select_common_type(typeids, "ARRAY");
/* Coerce arguments to common type if necessary */
foreach(element, newelems)
{
Node *e = (Node *) lfirst(element);
Node *newe;
newe = coerce_to_common_type(pstate, e,
element_type,
"ARRAY");
newcoercedelems = lappend(newcoercedelems, newe);
}
/* Do we have an array type to use? */
array_type = get_array_type(element_type);
if (array_type != InvalidOid)
{
/* Elements are presumably of scalar type */
newa->multidims = false;
}
else
{
/* Must be nested array expressions */
newa->multidims = true;
array_type = element_type;
element_type = get_element_type(array_type);
if (!OidIsValid(element_type))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("could not find array type for data type %s",
format_type_be(array_type))));
}
newa->array_typeid = array_type;
newa->element_typeid = element_type;
newa->elements = newcoercedelems;
return (Node *) newa;
}
static Node *
transformRowExpr(ParseState *pstate, RowExpr *r)
{
RowExpr *newr = makeNode(RowExpr);
/* Transform the field expressions */
newr->args = transformExpressionList(pstate, r->args);
/* Barring later casting, we consider the type RECORD */
newr->row_typeid = RECORDOID;
newr->row_format = COERCE_IMPLICIT_CAST;
return (Node *) newr;
}
static Node *
transformTableValueExpr(ParseState *pstate, TableValueExpr *t)
{
List *parsetrees;
Query *query;
/* If we already transformed this node, do nothing */
if (IsA(t->subquery, Query))
return (Node*) t;
/*
* Table Value Expressions are subselects that can occur as parameters to
* functions. One result of this is that this code shares a lot with
* transformRangeSubselect due to the nature of subquery resolution.
*/
pstate->p_hasTblValueExpr = true;
/* Analyze and transform the subquery */
parsetrees = parse_sub_analyze(t->subquery, pstate);
/*
* Check that we got something reasonable. Most of these conditions
* are probably impossible given restrictions in the grammar.
*/
Insist(list_length(parsetrees) == 1);
query = (Query *) linitial(parsetrees);
if (query == NULL || !IsA(query, Query))
elog(ERROR, "unexpected non-SELECT command in TableValueExpr");
if (query->commandType != CMD_SELECT)
elog(ERROR, "unexpected non-SELECT command in TableValueExpr");
if (query->intoClause != NULL)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("subquery in TABLE value expression cannot have SELECT INTO"),
errOmitLocation(true),
parser_errposition(pstate, t->location)));
t->subquery = (Node*) query;
/*
* Insist that the TABLE value expression does not contain references to the outer
* range table, this would be an unsupported correlated TABLE value expression.
*/
if (contain_vars_of_level_or_above((Node *) query, 1))
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("subquery in TABLE value expression may not refer "
"to relation of another query level"),
errOmitLocation(true),
parser_errposition(pstate, t->location)));
return (Node*) t;
}
static Node *
transformCoalesceExpr(ParseState *pstate, CoalesceExpr *c)
{
CoalesceExpr *newc = makeNode(CoalesceExpr);
List *newargs = NIL;
List *newcoercedargs = NIL;
List *typeids = NIL;
ListCell *args;
foreach(args, c->args)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = transformExpr(pstate, e);
newargs = lappend(newargs, newe);
typeids = lappend_oid(typeids, exprType(newe));
}
newc->coalescetype = select_common_type(typeids, "COALESCE");
/* Convert arguments if necessary */
foreach(args, newargs)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = coerce_to_common_type(pstate, e,
newc->coalescetype,
"COALESCE");
newcoercedargs = lappend(newcoercedargs, newe);
}
newc->args = newcoercedargs;
return (Node *) newc;
}
static Node *
transformMinMaxExpr(ParseState *pstate, MinMaxExpr *m)
{
MinMaxExpr *newm = makeNode(MinMaxExpr);
List *newargs = NIL;
List *newcoercedargs = NIL;
List *typeids = NIL;
ListCell *args;
newm->op = m->op;
foreach(args, m->args)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = transformExpr(pstate, e);
newargs = lappend(newargs, newe);
typeids = lappend_oid(typeids, exprType(newe));
}
newm->minmaxtype = select_common_type(typeids, "GREATEST/LEAST");
/* Convert arguments if necessary */
foreach(args, newargs)
{
Node *e = (Node *) lfirst(args);
Node *newe;
newe = coerce_to_common_type(pstate, e,
newm->minmaxtype,
"GREATEST/LEAST");
newcoercedargs = lappend(newcoercedargs, newe);
}
newm->args = newcoercedargs;
return (Node *) newm;
}
static Node *
transformBooleanTest(ParseState *pstate, BooleanTest *b)
{
const char *clausename;
switch (b->booltesttype)
{
case IS_TRUE:
clausename = "IS TRUE";
break;
case IS_NOT_TRUE:
clausename = "IS NOT TRUE";
break;
case IS_FALSE:
clausename = "IS FALSE";
break;
case IS_NOT_FALSE:
clausename = "IS NOT FALSE";
break;
case IS_UNKNOWN:
clausename = "IS UNKNOWN";
break;
case IS_NOT_UNKNOWN:
clausename = "IS NOT UNKNOWN";
break;
default:
elog(ERROR, "unrecognized booltesttype: %d",
(int) b->booltesttype);
clausename = NULL; /* keep compiler quiet */
}
b->arg = (Expr *) transformExpr(pstate, (Node *) b->arg);
b->arg = (Expr *) coerce_to_boolean(pstate,
(Node *) b->arg,
clausename);
return (Node *) b;
}
/*
* Construct a whole-row reference to represent the notation "relation.*".
*
* A whole-row reference is a Var with varno set to the correct range
* table entry, and varattno == 0 to signal that it references the whole
* tuple. (Use of zero here is unclean, since it could easily be confused
* with error cases, but it's not worth changing now.) The vartype indicates
* a rowtype; either a named composite type, or RECORD.
*/
static Node *
transformWholeRowRef(ParseState *pstate, char *catalogname, char *schemaname, char *relname,
int location)
{
Node *result;
RangeTblEntry *rte;
int vnum;
int sublevels_up;
Oid toid;
/* Look up the referenced RTE, creating it if needed */
rte = refnameRangeTblEntry(pstate, catalogname, schemaname, relname, location,
&sublevels_up);
if (rte == NULL)
rte = addImplicitRTE(pstate, makeRangeVar(catalogname, schemaname, relname, location), location);
vnum = RTERangeTablePosn(pstate, rte, &sublevels_up);
/* Build the appropriate referencing node */
switch (rte->rtekind)
{
case RTE_RELATION:
/* relation: the rowtype is a named composite type */
toid = get_rel_type_id(rte->relid);
if (!OidIsValid(toid))
elog(ERROR, "could not find type OID for relation %u",
rte->relid);
result = (Node *) makeVar(vnum,
InvalidAttrNumber,
toid,
-1,
sublevels_up);
break;
case RTE_TABLEFUNCTION:
case RTE_FUNCTION:
toid = exprType(rte->funcexpr);
if (toid == RECORDOID || get_typtype(toid) == 'c')
{
/* func returns composite; same as relation case */
result = (Node *) makeVar(vnum,
InvalidAttrNumber,
toid,
-1,
sublevels_up);
}
else
{
/*
* func returns scalar; instead of making a whole-row Var,
* just reference the function's scalar output. (XXX this
* seems a tad inconsistent, especially if "f.*" was
* explicitly written ...)
*/
result = (Node *) makeVar(vnum,
1,
toid,
-1,
sublevels_up);
}
break;
case RTE_VALUES:
toid = RECORDOID;
/* returns composite; same as relation case */
result = (Node *) makeVar(vnum,
InvalidAttrNumber,
toid,
-1,
sublevels_up);
break;
default:
/*
* RTE is a join or subselect. We represent this as a whole-row
* Var of RECORD type. (Note that in most cases the Var will be
* expanded to a RowExpr during planning, but that is not our
* concern here.)
*/
result = (Node *) makeVar(vnum,
InvalidAttrNumber,
RECORDOID,
-1,
sublevels_up);
break;
}
return result;
}
static Node *
transformGroupingFunc(ParseState *pstate, GroupingFunc *gf)
{
List *targs = NIL;
ListCell *lc;
GroupingFunc *new_gf;
new_gf = makeNode(GroupingFunc);
/*
* Transform the list of arguments.
*/
foreach (lc, gf->args)
targs = lappend(targs, transformExpr(pstate, (Node *)lfirst(lc)));
new_gf->args = targs;
new_gf->ngrpcols = gf->ngrpcols;
return (Node *)new_gf;
}
/*
* Returns string which represents percentile signature.
* sorttypes and sortlen can be omitted if they are unknown.
*/
static char *
percentileFuncString(PercentileExpr *p, Oid *argtypes, int arglen,
Oid *sorttypes, int sortlen)
{
StringInfoData buf;
char *funcname = NULL;
int i;
if (p->perckind == PERC_MEDIAN)
funcname = "median";
else if (p->perckind == PERC_CONT)
funcname = "percentile_cont";
else if (p->perckind == PERC_DISC)
funcname = "percentile_disc";
else
elog(ERROR, "unexpected perckind: %d", (int) p->perckind);
initStringInfo(&buf);
if (p->perckind == PERC_MEDIAN)
appendStringInfo(&buf, "%s",
func_signature_string(list_make1(makeString(funcname)),
sortlen, sorttypes));
else
{
appendStringInfo(&buf, "%s",
func_signature_string(list_make1(makeString(funcname)),
arglen, argtypes));
if (sortlen > 0)
{
appendStringInfo(&buf, " ORDER BY (");
for (i = 0 ; i < sortlen; i++)
{
appendStringInfo(&buf, "%s", format_type_be(sorttypes[i]));
if (i != sortlen - 1)
appendStringInfo(&buf, ", ");
}
appendStringInfo(&buf, ")");
}
}
return pstrdup(buf.data);
}
/*
* transformPercentileExpr
*
* Its argument expression and ORDER BY clause are transformed.
* Various syntax checks are also done here.
*/
static Node *
transformPercentileExpr(ParseState *pstate, PercentileExpr *p)
{
Node *arg;
Oid argtype;
AttrNumber save_next_resno;
/* args should be one for the moment, but can be extended later. */
Assert(list_length(p->args) == 1);
arg = transformExpr(pstate, linitial(p->args));
argtype = exprType(arg);
if (!IsBinaryCoercible(argtype, FLOAT8OID))
{
arg = coerce_to_target_type(pstate, arg, argtype,
FLOAT8OID, -1, COERCION_EXPLICIT,
COERCE_EXPLICIT_CALL, p->location);
/*
* The argument cannot be cast to the desired type.
*/
if (!arg)
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("function \"%s\" does not exist",
percentileFuncString(p, &argtype, 1, NULL, 0)),
errhint("No function matches the given name and argument types. "
"You may need to add explicit type casts.")));
}
argtype = FLOAT8OID;
/*
* The argument check is almost same as LIMIT clause.
*/
if (contain_vars_of_level(arg, 0))
ereport(ERROR,
(errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("argument of percentile function must not contain variables")));
if (checkExprHasAggs(arg))
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("argument of percentile function must not contain aggregates")));
if (checkExprHasWindFuncs(arg))
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("argument of percentile function must not contain window functions")));
if (checkExprHasGroupExtFuncs(arg))
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("argument of percentile function must not contain grouping(), or group_id()")));
/*
* The argument should be stable within a group. We don't know what is the
* right behavior for the volatile argument. Simply erroring out for now.
*/
if (contain_volatile_functions(arg))
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("argument of percentile function must not contain volatile functions")));
/*
* It might be possible to support SubLink in the argument, but the limitation
* here is as LIMIT clause. Erroring out for now.
*/
if (checkExprHasSubLink(arg))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("argument of percentile function must not contain subqueries")));
/*
* Percentile functions support only one sort key.
*/
if (list_length(p->sortClause) != 1)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("function \"%s\" cannot accept more than one expression in ORDER BY",
percentileFuncString(p, &argtype, 1, NULL, 0))));
p->args = list_make1(arg);
/*
* sortClause should not be transformed twice, and !sortTargets is
* not a good test to know if it's done, but it's ok for now.
*/
if (!p->sortTargets)
{
List *tlist = NIL, *sortlist = NIL, *pre_tlist = NIL;
ListCell *l;
int i;
int min_varlevel;
int sortlen;
Oid *sorttypes;
struct _FuncCandidateList float8_sig,
timestamp_sig,
timestamptz_sig,
interval_sig,
*candidates;
int ncandidates;
/*
* This part is similar to transformSortClause(), but there is a reason
* we are not able to use it; each expression should be coerced to
* the type this function desires, as the argument expressions are treated.
* Also, another task is function resolution by input types.
* As we consider ORDER BY clause as arguments, the resolution process
* is different from normal func_get_detail(). Though, some parts
* can be shared without reinventing.
*
* Save resno and start from 1 for only this part of transformation.
*/
save_next_resno = pstate->p_next_resno;
pstate->p_next_resno = 1;
sortlen = list_length(p->sortClause);
sorttypes = (Oid *) palloc0(sizeof(Oid) * sortlen);
foreach_with_count (l, p->sortClause, i)
{
SortBy *sortby = lfirst(l);
Node *expr;
TargetEntry *tle;
Oid sorttype;
expr = transformExpr(pstate, sortby->node);
tle = transformTargetEntry(pstate, sortby->node, expr, NULL, true);
sorttype = exprType((Node *) tle->expr);
sorttypes[i] = sorttype;
pre_tlist = lappend(pre_tlist, tle);
}
/*
* The logic for function resolution is same as the normal case except
* that we look for candidates by ORDER BY clause. Because PercentileExpr
* supports limited number of data types, we write possible types here manually.
* The code should look similar to func_get_detail().
*/
float8_sig.nargs = 1;
float8_sig.args[0] = FLOAT8OID;
timestamp_sig.nargs = 1;
timestamp_sig.args[0] = TIMESTAMPOID;
timestamptz_sig.nargs = 1;
timestamptz_sig.args[0] = TIMESTAMPTZOID;
interval_sig.nargs = 1;
interval_sig.args[0] = INTERVALOID;
float8_sig.next = &timestamp_sig;
timestamp_sig.next = &timestamptz_sig;
timestamptz_sig.next = &interval_sig;
interval_sig.next = NULL;
ncandidates = func_match_argtypes(sortlen, sorttypes, &float8_sig, &candidates);
/*
* Multiple candidates? then better decide or throw an error...
*/
if (ncandidates > 1)
{
candidates = func_select_candidate(sortlen, sorttypes, candidates);
if (!candidates)
ereport(ERROR,
(errcode(ERRCODE_AMBIGUOUS_FUNCTION),
errmsg("function \"%s\" is not unique",
percentileFuncString(p, &argtype, 1, sorttypes, sortlen)),
errhint("Could not choose a best candidate function. "
"You may need to add explicit type casts.")));
}
else if (ncandidates == 0)
{
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_FUNCTION),
errmsg("function \"%s\" does not exist",
percentileFuncString(p, &argtype, 1, sorttypes, sortlen)),
errhint("No function matches the given name and argument types. "
"You may need to add explicit type casts.")));
}
p->perctype = candidates->args[0];
/*
* Coerce each of ORDER BY clause to the types which this function desires.
*/
foreach_with_count (l, pre_tlist, i)
{
TargetEntry *tle = lfirst(l);
Oid sorttype = sorttypes[i];
Oid candtype = candidates->args[i];
SortBy *sortby = list_nth(p->sortClause, i);
if (!IsBinaryCoercible(sorttype, candtype))
{
tle->expr = (Expr *) coerce_to_target_type(pstate,
(Node *) tle->expr,
sorttype,
candtype,
-1,
COERCION_EXPLICIT,
COERCE_EXPLICIT_CALL,
p->location);
/*
* Cast should succeed as we checked above.
*/
Assert(tle->expr);
}
tlist = lappend(tlist, tle);
/*
* Now we can add this target entry to the list.
*/
sortlist = addTargetToSortList(pstate, tle,
sortlist, tlist,
sortby->sortby_kind,
sortby->useOp,
true);
}
p->sortClause = sortlist;
p->sortTargets = tlist;
pfree(sorttypes);
/*
* Restore back the saved resno.
*/
pstate->p_next_resno = save_next_resno;
/*
* Although its argument is not allowed to refer to any Var,
* ORDER BY is allowed. Since PercentileExpr is semantically Aggref,
* when it refers to outer vars, the whole expression should be
* treated as an outer var. However, it is too invasive to do it
* for PercentileExpr, and as we plan to integrate it Aggref, we
* just disallow such cases for now. Revisit later.
*/
min_varlevel = find_minimum_var_level((Node *) p->sortTargets);
if (min_varlevel > 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("percentile functions cannot reference columns from outer queries")));
if (checkExprHasAggs((Node *) p->sortTargets))
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("argument of percentile function must not contain aggregates")));
if (checkExprHasWindFuncs((Node *) p->sortTargets))
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("argument of percentile function must not contain window functions")));
if (checkExprHasGroupExtFuncs((Node *) p->sortTargets))
ereport(ERROR,
(errcode(ERRCODE_GROUPING_ERROR),
errmsg("argument of percentile function must not contain grouping(), or group_id()")));
}
/* Percentiles are actually aggregates. */
pstate->p_hasAggs = true;
return (Node *) p;
}
/*
* exprType -
* returns the Oid of the type of the expression. (Used for typechecking.)
*/
Oid
exprType(Node *expr)
{
Oid type;
if (!expr)
return InvalidOid;
switch (nodeTag(expr))
{
case T_Var:
type = ((Var *) expr)->vartype;
break;
case T_Const:
type = ((Const *) expr)->consttype;
break;
case T_Param:
type = ((Param *) expr)->paramtype;
break;
case T_Aggref:
type = ((Aggref *) expr)->aggtype;
break;
case T_WindowRef:
type = ((WindowRef *) expr)->restype;
break;
case T_ArrayRef:
type = ((ArrayRef *) expr)->refrestype;
break;
case T_FuncExpr:
type = ((FuncExpr *) expr)->funcresulttype;
break;
case T_OpExpr:
type = ((OpExpr *) expr)->opresulttype;
break;
case T_DistinctExpr:
type = ((DistinctExpr *) expr)->opresulttype;
break;
case T_ScalarArrayOpExpr:
type = BOOLOID;
break;
case T_BoolExpr:
type = BOOLOID;
break;
case T_SubLink:
{
SubLink *sublink = (SubLink *) expr;
if (sublink->subLinkType == EXPR_SUBLINK ||
sublink->subLinkType == ARRAY_SUBLINK)
{
/* get the type of the subselect's first target column */
Query *qtree = (Query *) sublink->subselect;
TargetEntry *tent;
if (!qtree || !IsA(qtree, Query))
elog(ERROR, "cannot get type for untransformed sublink");
tent = (TargetEntry *) linitial(qtree->targetList);
Assert(IsA(tent, TargetEntry));
Assert(!tent->resjunk);
type = exprType((Node *) tent->expr);
if (sublink->subLinkType == ARRAY_SUBLINK)
{
type = get_array_type(type);
if (!OidIsValid(type))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("could not find array type for data type %s",
format_type_be(exprType((Node *) tent->expr)))));
}
}
else
{
/* for all other sublink types, result is boolean */
type = BOOLOID;
}
}
break;
case T_SubPlan:
{
/*
* Although the parser does not ever deal with already-planned
* expression trees, we support SubPlan nodes in this routine
* for the convenience of ruleutils.c.
*/
SubPlan *subplan = (SubPlan *) expr;
if (subplan->subLinkType == EXPR_SUBLINK ||
subplan->subLinkType == ARRAY_SUBLINK)
{
/* get the type of the subselect's first target column */
Oid itemtype = subplan->firstColType;
type = itemtype;
if (subplan->subLinkType == ARRAY_SUBLINK)
{
type = get_array_type(itemtype);
if (!OidIsValid(type))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("could not find array type for data type %s",
format_type_be(itemtype))));
}
}
else
{
/* for all other subplan types, result is boolean */
type = BOOLOID;
}
}
break;
case T_FieldSelect:
type = ((FieldSelect *) expr)->resulttype;
break;
case T_FieldStore:
type = ((FieldStore *) expr)->resulttype;
break;
case T_RelabelType:
type = ((RelabelType *) expr)->resulttype;
break;
case T_ConvertRowtypeExpr:
type = ((ConvertRowtypeExpr *) expr)->resulttype;
break;
case T_CaseExpr:
type = ((CaseExpr *) expr)->casetype;
break;
case T_CaseWhen:
type = exprType((Node *) ((CaseWhen *) expr)->result);
break;
case T_CaseTestExpr:
type = ((CaseTestExpr *) expr)->typeId;
break;
case T_ArrayExpr:
type = ((ArrayExpr *) expr)->array_typeid;
break;
case T_RowExpr:
type = ((RowExpr *) expr)->row_typeid;
break;
case T_TableValueExpr:
type = ANYTABLEOID; /* MULTISET values are a special pseudotype */
break;
case T_RowCompareExpr:
type = BOOLOID;
break;
case T_CoalesceExpr:
type = ((CoalesceExpr *) expr)->coalescetype;
break;
case T_MinMaxExpr:
type = ((MinMaxExpr *) expr)->minmaxtype;
break;
case T_NullIfExpr:
type = exprType((Node *) linitial(((NullIfExpr *) expr)->args));
break;
case T_NullTest:
type = BOOLOID;
break;
case T_BooleanTest:
type = BOOLOID;
break;
case T_CoerceToDomain:
type = ((CoerceToDomain *) expr)->resulttype;
break;
case T_CoerceToDomainValue:
type = ((CoerceToDomainValue *) expr)->typeId;
break;
case T_SetToDefault:
type = ((SetToDefault *) expr)->typeId;
break;
case T_CurrentOfExpr:
type = BOOLOID;
break;
case T_GroupingFunc:
type = INT8OID;
break;
case T_Grouping:
type = INT8OID;
break;
case T_GroupId:
type = INT4OID;
break;
case T_PercentileExpr:
type = ((PercentileExpr *) expr)->perctype;
break;
case T_DMLActionExpr:
type = INT4OID;
break;
case T_PartOidExpr:
type = OIDOID;
break;
case T_PartDefaultExpr:
type = BOOLOID;
break;
case T_PartBoundExpr:
type = ((PartBoundExpr *) expr)->boundType;
break;
case T_PartBoundInclusionExpr:
type = BOOLOID;
break;
case T_PartBoundOpenExpr:
type = BOOLOID;
break;
default:
elog(ERROR, "unrecognized node type: %d", (int) nodeTag(expr));
type = InvalidOid; /* keep compiler quiet */
break;
}
return type;
}
/*
* exprTypmod -
* returns the type-specific attrmod of the expression, if it can be
* determined. In most cases, it can't and we return -1.
*/
int32
exprTypmod(Node *expr)
{
if (!expr)
return -1;
switch (nodeTag(expr))
{
case T_Var:
return ((Var *) expr)->vartypmod;
case T_Const:
{
/* Be smart about string constants... */
Const *con = (Const *) expr;
switch (con->consttype)
{
case BPCHAROID:
if (!con->constisnull)
{
int32 len = VARSIZE(DatumGetPointer(con->constvalue)) - VARHDRSZ;
/* if multi-byte, take len and find # characters */
if (pg_database_encoding_max_length() > 1)
len = pg_mbstrlen_with_len(VARDATA(DatumGetPointer(con->constvalue)), len);
return len + VARHDRSZ;
}
break;
default:
break;
}
}
break;
case T_FuncExpr:
{
int32 coercedTypmod;
/* Be smart about length-coercion functions... */
if (exprIsLengthCoercion(expr, &coercedTypmod))
return coercedTypmod;
}
break;
case T_FieldSelect:
return ((FieldSelect *) expr)->resulttypmod;
case T_RelabelType:
return ((RelabelType *) expr)->resulttypmod;
case T_CaseExpr:
{
/*
* If all the alternatives agree on type/typmod, return that
* typmod, else use -1
*/
CaseExpr *cexpr = (CaseExpr *) expr;
Oid casetype = cexpr->casetype;
int32 typmod;
ListCell *arg;
if (!cexpr->defresult)
return -1;
if (exprType((Node *) cexpr->defresult) != casetype)
return -1;
typmod = exprTypmod((Node *) cexpr->defresult);
if (typmod < 0)
return -1; /* no point in trying harder */
foreach(arg, cexpr->args)
{
CaseWhen *w = (CaseWhen *) lfirst(arg);
Assert(IsA(w, CaseWhen));
if (exprType((Node *) w->result) != casetype)
return -1;
if (exprTypmod((Node *) w->result) != typmod)
return -1;
}
return typmod;
}
break;
case T_CaseTestExpr:
return ((CaseTestExpr *) expr)->typeMod;
case T_CoalesceExpr:
{
/*
* If all the alternatives agree on type/typmod, return that
* typmod, else use -1
*/
CoalesceExpr *cexpr = (CoalesceExpr *) expr;
Oid coalescetype = cexpr->coalescetype;
int32 typmod;
ListCell *arg;
if (exprType((Node *) linitial(cexpr->args)) != coalescetype)
return -1;
typmod = exprTypmod((Node *) linitial(cexpr->args));
if (typmod < 0)
return -1; /* no point in trying harder */
for_each_cell(arg, lnext(list_head(cexpr->args)))
{
Node *e = (Node *) lfirst(arg);
if (exprType(e) != coalescetype)
return -1;
if (exprTypmod(e) != typmod)
return -1;
}
return typmod;
}
break;
case T_MinMaxExpr:
{
/*
* If all the alternatives agree on type/typmod, return that
* typmod, else use -1
*/
MinMaxExpr *mexpr = (MinMaxExpr *) expr;
Oid minmaxtype = mexpr->minmaxtype;
int32 typmod;
ListCell *arg;
if (exprType((Node *) linitial(mexpr->args)) != minmaxtype)
return -1;
typmod = exprTypmod((Node *) linitial(mexpr->args));
if (typmod < 0)
return -1; /* no point in trying harder */
for_each_cell(arg, lnext(list_head(mexpr->args)))
{
Node *e = (Node *) lfirst(arg);
if (exprType(e) != minmaxtype)
return -1;
if (exprTypmod(e) != typmod)
return -1;
}
return typmod;
}
break;
case T_NullIfExpr:
{
NullIfExpr *nexpr = (NullIfExpr *) expr;
return exprTypmod((Node *) linitial(nexpr->args));
}
break;
case T_CoerceToDomain:
return ((CoerceToDomain *) expr)->resulttypmod;
case T_CoerceToDomainValue:
return ((CoerceToDomainValue *) expr)->typeMod;
case T_SetToDefault:
return ((SetToDefault *) expr)->typeMod;
default:
break;
}
return -1;
}
/*
* exprIsLengthCoercion
* Detect whether an expression tree is an application of a datatype's
* typmod-coercion function. Optionally extract the result's typmod.
*
* If coercedTypmod is not NULL, the typmod is stored there if the expression
* is a length-coercion function, else -1 is stored there.
*
* Note that a combined type-and-length coercion will be treated as a
* length coercion by this routine.
*/
bool
exprIsLengthCoercion(Node *expr, int32 *coercedTypmod)
{
FuncExpr *func;
int nargs;
Const *second_arg;
if (coercedTypmod != NULL)
*coercedTypmod = -1; /* default result on failure */
/* Is it a function-call at all? */
if (expr == NULL || !IsA(expr, FuncExpr))
return false;
func = (FuncExpr *) expr;
/*
* If it didn't come from a coercion context, reject.
*/
if (func->funcformat != COERCE_EXPLICIT_CAST &&
func->funcformat != COERCE_IMPLICIT_CAST)
return false;
/*
* If it's not a two-argument or three-argument function with the second
* argument being an int4 constant, it can't have been created from a
* length coercion (it must be a type coercion, instead).
*/
nargs = list_length(func->args);
if (nargs < 2 || nargs > 3)
return false;
second_arg = (Const *) lsecond(func->args);
if (!IsA(second_arg, Const) ||
second_arg->consttype != INT4OID ||
second_arg->constisnull)
return false;
/*
* OK, it is indeed a length-coercion function.
*/
if (coercedTypmod != NULL)
*coercedTypmod = DatumGetInt32(second_arg->constvalue);
return true;
}
/*
* Handle an explicit CAST construct.
*
* The given expr has already been transformed, but we need to lookup
* the type name and then apply any necessary coercion function(s).
*/
static Node *
typecast_expression(ParseState *pstate, Node *expr, TypeName *typname)
{
Oid inputType = exprType(expr);
Oid targetType;
targetType = typenameTypeId(pstate, typname);
if (inputType == InvalidOid)
return expr; /* do nothing if NULL input */
expr = coerce_to_target_type(pstate, expr, inputType,
targetType, typname->typmod,
COERCION_EXPLICIT,
COERCE_EXPLICIT_CAST,
-1);
if (expr == NULL)
ereport(ERROR,
(errcode(ERRCODE_CANNOT_COERCE),
errmsg("cannot cast type %s to %s",
format_type_be(inputType),
format_type_be(targetType)),
errOmitLocation(true),
parser_errposition(pstate, typname->location)));
return expr;
}
/*
* Transform a "row compare-op row" construct
*
* The inputs are lists of already-transformed expressions.
* As with coerce_type, pstate may be NULL if no special unknown-Param
* processing is wanted.
*
* The output may be a single OpExpr, an AND or OR combination of OpExprs,
* or a RowCompareExpr. In all cases it is guaranteed to return boolean.
* The AND, OR, and RowCompareExpr cases further imply things about the
* behavior of the operators (ie, they behave as =, <>, or < <= > >=).
*/
static Node *
make_row_comparison_op(ParseState *pstate, List *opname,
List *largs, List *rargs, int location)
{
RowCompareExpr *rcexpr;
RowCompareType rctype;
List *opexprs;
List *opnos;
List *opclasses;
ListCell *l,
*r;
List **opclass_lists;
List **opstrat_lists;
Bitmapset *strats;
int nopers;
int i;
nopers = list_length(largs);
if (nopers != list_length(rargs))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unequal number of entries in row expressions"),
errOmitLocation(true),
parser_errposition(pstate, location)));
/*
* We can't compare zero-length rows because there is no principled basis
* for figuring out what the operator is.
*/
if (nopers == 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot compare rows of zero length"),
errOmitLocation(true),
parser_errposition(pstate, location)));
/*
* Identify all the pairwise operators, using make_op so that behavior is
* the same as in the simple scalar case.
*/
opexprs = NIL;
forboth(l, largs, r, rargs)
{
Node *larg = (Node *) lfirst(l);
Node *rarg = (Node *) lfirst(r);
OpExpr *cmp;
cmp = (OpExpr *) make_op(pstate, opname, larg, rarg, location);
Assert(IsA(cmp, OpExpr));
/*
* We don't use coerce_to_boolean here because we insist on the
* operator yielding boolean directly, not via coercion. If it
* doesn't yield bool it won't be in any index opclasses...
*/
if (cmp->opresulttype != BOOLOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("row comparison operator must yield type boolean, "
"not type %s",
format_type_be(cmp->opresulttype)),
errOmitLocation(true),
parser_errposition(pstate, location)));
if (expression_returns_set((Node *) cmp))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("row comparison operator must not return a set"),
errOmitLocation(true),
parser_errposition(pstate, location)));
opexprs = lappend(opexprs, cmp);
}
/*
* If rows are length 1, just return the single operator. In this case we
* don't insist on identifying btree semantics for the operator (but we
* still require it to return boolean).
*/
if (nopers == 1)
return (Node *) linitial(opexprs);
/*
* Now we must determine which row comparison semantics (= <> < <= > >=)
* apply to this set of operators. We look for btree opclasses containing
* the operators, and see which interpretations (strategy numbers) exist
* for each operator.
*/
opclass_lists = (List **) palloc(nopers * sizeof(List *));
opstrat_lists = (List **) palloc(nopers * sizeof(List *));
strats = NULL;
i = 0;
foreach(l, opexprs)
{
Bitmapset *this_strats;
ListCell *j;
get_op_btree_interpretation(((OpExpr *) lfirst(l))->opno,
&opclass_lists[i], &opstrat_lists[i]);
/*
* convert strategy number list to a Bitmapset to make the
* intersection calculation easy.
*/
this_strats = NULL;
foreach(j, opstrat_lists[i])
{
this_strats = bms_add_member(this_strats, lfirst_int(j));
}
if (i == 0)
strats = this_strats;
else
strats = bms_int_members(strats, this_strats);
i++;
}
switch (bms_membership(strats))
{
case BMS_EMPTY_SET:
/* No common interpretation, so fail */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not determine interpretation of row comparison operator %s",
strVal(llast(opname))),
errhint("Row comparison operators must be associated with btree operator classes."),
errOmitLocation(true),
parser_errposition(pstate, location)));
rctype = 0; /* keep compiler quiet */
break;
case BMS_SINGLETON:
/* Simple case: just one possible interpretation */
rctype = bms_singleton_member(strats);
break;
case BMS_MULTIPLE:
default: /* keep compiler quiet */
{
/*
* Prefer the interpretation with the most default opclasses.
*/
int best_defaults = 0;
bool multiple_best = false;
int this_rctype;
rctype = 0; /* keep compiler quiet */
while ((this_rctype = bms_first_member(strats)) >= 0)
{
int ndefaults = 0;
for (i = 0; i < nopers; i++)
{
forboth(l, opclass_lists[i], r, opstrat_lists[i])
{
Oid opclass = lfirst_oid(l);
int opstrat = lfirst_int(r);
if (opstrat == this_rctype &&
opclass_is_default(opclass))
ndefaults++;
}
}
if (ndefaults > best_defaults)
{
best_defaults = ndefaults;
rctype = this_rctype;
multiple_best = false;
}
else if (ndefaults == best_defaults)
multiple_best = true;
}
if (best_defaults == 0 || multiple_best)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not determine interpretation of row comparison operator %s",
strVal(llast(opname))),
errdetail("There are multiple equally-plausible candidates."),
errOmitLocation(true),
parser_errposition(pstate, location)));
break;
}
}
/*
* For = and <> cases, we just combine the pairwise operators with AND or
* OR respectively.
*
* Note: this is presently the only place where the parser generates
* BoolExpr with more than two arguments. Should be OK since the rest of
* the system thinks BoolExpr is N-argument anyway.
*/
if (rctype == ROWCOMPARE_EQ)
return (Node *) makeBoolExpr(AND_EXPR, opexprs, location);
if (rctype == ROWCOMPARE_NE)
return (Node *) makeBoolExpr(OR_EXPR, opexprs, location);
/*
* Otherwise we need to determine exactly which opclass to associate with
* each operator.
*/
opclasses = NIL;
for (i = 0; i < nopers; i++)
{
Oid best_opclass = 0;
int ndefault = 0;
int nmatch = 0;
forboth(l, opclass_lists[i], r, opstrat_lists[i])
{
Oid opclass = lfirst_oid(l);
int opstrat = lfirst_int(r);
if (opstrat == rctype)
{
if (ndefault == 0)
best_opclass = opclass;
if (opclass_is_default(opclass))
ndefault++;
else
nmatch++;
}
}
if (ndefault == 1 || (ndefault == 0 && nmatch == 1))
opclasses = lappend_oid(opclasses, best_opclass);
else
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("could not determine interpretation of row comparison operator %s",
strVal(llast(opname))),
errdetail("There are multiple equally-plausible candidates."),
errOmitLocation(true),
parser_errposition(pstate, location)));
}
/*
* Now deconstruct the OpExprs and create a RowCompareExpr.
*
* Note: can't just reuse the passed largs/rargs lists, because of
* possibility that make_op inserted coercion operations.
*/
opnos = NIL;
largs = NIL;
rargs = NIL;
foreach(l, opexprs)
{
OpExpr *cmp = (OpExpr *) lfirst(l);
opnos = lappend_oid(opnos, cmp->opno);
largs = lappend(largs, linitial(cmp->args));
rargs = lappend(rargs, lsecond(cmp->args));
}
rcexpr = makeNode(RowCompareExpr);
rcexpr->rctype = rctype;
rcexpr->opnos = opnos;
rcexpr->opclasses = opclasses;
rcexpr->largs = largs;
rcexpr->rargs = rargs;
return (Node *) rcexpr;
}
/*
* Transform a "row IS DISTINCT FROM row" construct
*
* The input RowExprs are already transformed
*/
static Node *
make_row_distinct_op(ParseState *pstate, List *opname,
RowExpr *lrow, RowExpr *rrow,
int location)
{
Node *result = NULL;
List *largs = lrow->args;
List *rargs = rrow->args;
ListCell *l,
*r;
if (list_length(largs) != list_length(rargs))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unequal number of entries in row expressions"),
errOmitLocation(true),
parser_errposition(pstate, location)));
forboth(l, largs, r, rargs)
{
Node *larg = (Node *) lfirst(l);
Node *rarg = (Node *) lfirst(r);
Node *cmp;
cmp = (Node *) make_distinct_op(pstate, opname, larg, rarg, location);
if (result == NULL)
result = cmp;
else
result = (Node *) makeBoolExpr(OR_EXPR,
list_make2(result, cmp), location);
}
if (result == NULL)
{
/* zero-length rows? Generate constant FALSE */
result = makeBoolConst(false, false);
}
return result;
}
/*
* make the node for an IS DISTINCT FROM operator
*/
static Expr *
make_distinct_op(ParseState *pstate, List *opname, Node *ltree, Node *rtree,
int location)
{
Expr *result;
result = make_op(pstate, opname, ltree, rtree, location);
if (((OpExpr *) result)->opresulttype != BOOLOID)
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("IS DISTINCT FROM requires = operator to yield boolean"),
errOmitLocation(true),
parser_errposition(pstate, location)));
/*
* We rely on DistinctExpr and OpExpr being same struct
*/
NodeSetTag(result, T_DistinctExpr);
return result;
}