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Implement SQL-compliant treatment of row comparisons for < <= > >= cases

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(previously we only did = and <> correctly).  Also, allow row comparisons
with any operators that are in btree opclasses, not only those with these
specific names.  This gets rid of a whole lot of indefensible assumptions
about the behavior of particular operators based on their names ... though
it's still true that IN and NOT IN expand to "= ANY".  The patch adds a
RowCompareExpr expression node type, and makes some changes in the
representation of ANY/ALL/ROWCOMPARE SubLinks so that they can share code
with RowCompareExpr.

I have not yet done anything about making RowCompareExpr an indexable
operator, but will look at that soon.

initdb forced due to changes in stored rules.
This commit is contained in:
Tom Lane
2005-12-28 01:30:02 +00:00
parent a37422e042
commit 6e07709760
26 changed files with 1452 additions and 659 deletions
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160
src/backend/utils/adt/ruleutils.c
View File

@ -3,7 +3,7 @@
* back to source text
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.210 2005/12/10 19:21:03 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.211 2005/12/28 01:30:00 tgl Exp $
*
* This software is copyrighted by Jan Wieck - Hamburg.
*
@ -215,7 +215,6 @@ static void printSubscripts(ArrayRef *aref, deparse_context *context);
static char *generate_relation_name(Oid relid);
static char *generate_function_name(Oid funcid, int nargs, Oid *argtypes);
static char *generate_operator_name(Oid operid, Oid arg1, Oid arg2);
static void print_operator_name(StringInfo buf, List *opname);
static text *string_to_text(char *str);
#define only_marker(rte) ((rte)->inh ? "" : "ONLY ")
@ -3106,6 +3105,7 @@ get_rule_expr(Node *node, deparse_context *context,
break;
case PARAM_NUM:
case PARAM_EXEC:
case PARAM_SUBLINK:
appendStringInfo(buf, "$%d", param->paramid);
break;
default:
@ -3514,6 +3514,50 @@ get_rule_expr(Node *node, deparse_context *context,
}
break;
case T_RowCompareExpr:
{
RowCompareExpr *rcexpr = (RowCompareExpr *) node;
ListCell *arg;
char *sep;
/*
* SQL99 allows "ROW" to be omitted when there is more than
* one column, but for simplicity we always print it.
*/
appendStringInfo(buf, "(ROW(");
sep = "";
foreach(arg, rcexpr->largs)
{
Node *e = (Node *) lfirst(arg);
appendStringInfoString(buf, sep);
get_rule_expr(e, context, true);
sep = ", ";
}
/*
* We assume that the name of the first-column operator
* will do for all the rest too. This is definitely
* open to failure, eg if some but not all operators
* were renamed since the construct was parsed, but there
* seems no way to be perfect.
*/
appendStringInfo(buf, ") %s ROW(",
generate_operator_name(linitial_oid(rcexpr->opnos),
exprType(linitial(rcexpr->largs)),
exprType(linitial(rcexpr->rargs))));
sep = "";
foreach(arg, rcexpr->rargs)
{
Node *e = (Node *) lfirst(arg);
appendStringInfoString(buf, sep);
get_rule_expr(e, context, true);
sep = ", ";
}
appendStringInfo(buf, "))");
}
break;
case T_CoalesceExpr:
{
CoalesceExpr *coalesceexpr = (CoalesceExpr *) node;
@ -3967,6 +4011,7 @@ get_sublink_expr(SubLink *sublink, deparse_context *context)
{
StringInfo buf = context->buf;
Query *query = (Query *) (sublink->subselect);
char *opname = NULL;
bool need_paren;
if (sublink->subLinkType == ARRAY_SUBLINK)
@ -3974,25 +4019,67 @@ get_sublink_expr(SubLink *sublink, deparse_context *context)
else
appendStringInfoChar(buf, '(');
if (sublink->lefthand != NIL)
/*
* Note that we print the name of only the first operator, when there
* are multiple combining operators. This is an approximation that
* could go wrong in various scenarios (operators in different schemas,
* renamed operators, etc) but there is not a whole lot we can do about
* it, since the syntax allows only one operator to be shown.
*/
if (sublink->testexpr)
{
need_paren = (list_length(sublink->lefthand) > 1);
if (need_paren)
if (IsA(sublink->testexpr, OpExpr))
{
/* single combining operator */
OpExpr *opexpr = (OpExpr *) sublink->testexpr;
get_rule_expr(linitial(opexpr->args), context, true);
opname = generate_operator_name(opexpr->opno,
exprType(linitial(opexpr->args)),
exprType(lsecond(opexpr->args)));
}
else if (IsA(sublink->testexpr, BoolExpr))
{
/* multiple combining operators, = or <> cases */
char *sep;
ListCell *l;
appendStringInfoChar(buf, '(');
get_rule_expr((Node *) sublink->lefthand, context, true);
if (need_paren)
sep = "";
foreach(l, ((BoolExpr *) sublink->testexpr)->args)
{
OpExpr *opexpr = (OpExpr *) lfirst(l);
Assert(IsA(opexpr, OpExpr));
appendStringInfoString(buf, sep);
get_rule_expr(linitial(opexpr->args), context, true);
if (!opname)
opname = generate_operator_name(opexpr->opno,
exprType(linitial(opexpr->args)),
exprType(lsecond(opexpr->args)));
sep = ", ";
}
appendStringInfoChar(buf, ')');
appendStringInfoChar(buf, ' ');
}
else if (IsA(sublink->testexpr, RowCompareExpr))
{
/* multiple combining operators, < <= > >= cases */
RowCompareExpr *rcexpr = (RowCompareExpr *) sublink->testexpr;
appendStringInfoChar(buf, '(');
get_rule_expr((Node *) rcexpr->largs, context, true);
opname = generate_operator_name(linitial_oid(rcexpr->opnos),
exprType(linitial(rcexpr->largs)),
exprType(linitial(rcexpr->rargs)));
appendStringInfoChar(buf, ')');
}
else
elog(ERROR, "unrecognized testexpr type: %d",
(int) nodeTag(sublink->testexpr));
}
need_paren = true;
/*
* XXX we regurgitate the originally given operator name, with or without
* schema qualification. This is not necessarily 100% right but it's the
* best we can do, since the operators actually used might not all be in
* the same schema.
*/
switch (sublink->subLinkType)
{
case EXISTS_SUBLINK:
@ -4000,27 +4087,18 @@ get_sublink_expr(SubLink *sublink, deparse_context *context)
break;
case ANY_SUBLINK:
if (list_length(sublink->operName) == 1 &&
strcmp(strVal(linitial(sublink->operName)), "=") == 0)
{
/* Represent = ANY as IN */
appendStringInfo(buf, "IN ");
}
if (strcmp(opname, "=") == 0) /* Represent = ANY as IN */
appendStringInfo(buf, " IN ");
else
{
print_operator_name(buf, sublink->operName);
appendStringInfo(buf, " ANY ");
}
appendStringInfo(buf, " %s ANY ", opname);
break;
case ALL_SUBLINK:
print_operator_name(buf, sublink->operName);
appendStringInfo(buf, " ALL ");
appendStringInfo(buf, " %s ALL ", opname);
break;
case MULTIEXPR_SUBLINK:
print_operator_name(buf, sublink->operName);
appendStringInfoChar(buf, ' ');
case ROWCOMPARE_SUBLINK:
appendStringInfo(buf, " %s ", opname);
break;
case EXPR_SUBLINK:
@ -4812,30 +4890,6 @@ generate_operator_name(Oid operid, Oid arg1, Oid arg2)
return buf.data;
}
/*
* Print out a possibly-qualified operator name
*/
static void
print_operator_name(StringInfo buf, List *opname)
{
ListCell *op = list_head(opname);
int nnames = list_length(opname);
if (nnames == 1)
appendStringInfoString(buf, strVal(lfirst(op)));
else
{
appendStringInfo(buf, "OPERATOR(");
while (nnames-- > 1)
{
appendStringInfo(buf, "%s.",
quote_identifier(strVal(lfirst(op))));
op = lnext(op);
}
appendStringInfo(buf, "%s)", strVal(lfirst(op)));
}
}
/*
* Given a C string, produce a TEXT datum.
*

144
src/backend/utils/cache/lsyscache.c vendored
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.130 2005/11/17 22:14:53 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.131 2005/12/28 01:30:01 tgl Exp $
*
* NOTES
* Eventually, the index information should go through here, too.
@ -183,6 +183,99 @@ get_op_hash_function(Oid opno)
return InvalidOid;
}
/*
* get_op_btree_interpretation
* Given an operator's OID, find out which btree opclasses it belongs to,
* and what strategy number it has within each one. The results are
* returned as an OID list and a parallel integer list.
*
* In addition to the normal btree operators, we consider a <> operator to be
* a "member" of an opclass if its negator is the opclass' equality operator.
* ROWCOMPARE_NE is returned as the strategy number for this case.
*/
void
get_op_btree_interpretation(Oid opno, List **opclasses, List **opstrats)
{
Oid lefttype,
righttype;
CatCList *catlist;
bool op_negated;
int i;
*opclasses = NIL;
*opstrats = NIL;
/*
* Get the nominal left-hand input type of the operator; we will ignore
* opclasses that don't have that as the expected input datatype. This
* is a kluge to avoid being confused by binary-compatible opclasses
* (such as text_ops and varchar_ops, which share the same operators).
*/
op_input_types(opno, &lefttype, &righttype);
Assert(OidIsValid(lefttype));
/*
* Find all the pg_amop entries containing the operator.
*/
catlist = SearchSysCacheList(AMOPOPID, 1,
ObjectIdGetDatum(opno),
0, 0, 0);
/*
* If we can't find any opclass containing the op, perhaps it is a
* <> operator. See if it has a negator that is in an opclass.
*/
op_negated = false;
if (catlist->n_members == 0)
{
Oid op_negator = get_negator(opno);
if (OidIsValid(op_negator))
{
op_negated = true;
ReleaseSysCacheList(catlist);
catlist = SearchSysCacheList(AMOPOPID, 1,
ObjectIdGetDatum(op_negator),
0, 0, 0);
}
}
/* Now search the opclasses */
for (i = 0; i < catlist->n_members; i++)
{
HeapTuple op_tuple = &catlist->members[i]->tuple;
Form_pg_amop op_form = (Form_pg_amop) GETSTRUCT(op_tuple);
Oid opclass_id;
StrategyNumber op_strategy;
opclass_id = op_form->amopclaid;
/* must be btree */
if (!opclass_is_btree(opclass_id))
continue;
/* must match operator input type exactly */
if (get_opclass_input_type(opclass_id) != lefttype)
continue;
/* Get the operator's btree strategy number */
op_strategy = (StrategyNumber) op_form->amopstrategy;
Assert(op_strategy >= 1 && op_strategy <= 5);
if (op_negated)
{
/* Only consider negators that are = */
if (op_strategy != BTEqualStrategyNumber)
continue;
op_strategy = ROWCOMPARE_NE;
}
*opclasses = lappend_oid(*opclasses, opclass_id);
*opstrats = lappend_int(*opstrats, op_strategy);
}
ReleaseSysCacheList(catlist);
}
/* ---------- AMPROC CACHES ---------- */
@ -433,6 +526,55 @@ opclass_is_hash(Oid opclass)
return result;
}
/*
* opclass_is_default
*
* Returns TRUE iff the specified opclass is the default for its
* index access method and input data type.
*/
bool
opclass_is_default(Oid opclass)
{
HeapTuple tp;
Form_pg_opclass cla_tup;
bool result;
tp = SearchSysCache(CLAOID,
ObjectIdGetDatum(opclass),
0, 0, 0);
if (!HeapTupleIsValid(tp))
elog(ERROR, "cache lookup failed for opclass %u", opclass);
cla_tup = (Form_pg_opclass) GETSTRUCT(tp);
result = cla_tup->opcdefault;
ReleaseSysCache(tp);
return result;
}
/*
* get_opclass_input_type
*
* Returns the OID of the datatype the opclass indexes.
*/
Oid
get_opclass_input_type(Oid opclass)
{
HeapTuple tp;
Form_pg_opclass cla_tup;
Oid result;
tp = SearchSysCache(CLAOID,
ObjectIdGetDatum(opclass),
0, 0, 0);
if (!HeapTupleIsValid(tp))
elog(ERROR, "cache lookup failed for opclass %u", opclass);
cla_tup = (Form_pg_opclass) GETSTRUCT(tp);
result = cla_tup->opcintype;
ReleaseSysCache(tp);
return result;
}
/* ---------- OPERATOR CACHE ---------- */
/*