* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.142 2007/01/09 02:14:14 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.143 2007/01/10 18:06:04 tgl Exp $
*
* NOTES
* Eventually, the index information should go through here, too.
#endif
/*
- * get_op_compare_function
+ * get_compare_function_for_ordering_op
* Get the OID of the datatype-specific btree comparison function
* associated with an ordering operator (a "<" or ">" operator).
*
* (This indicates that the operator is not a valid ordering operator.)
*/
bool
-get_op_compare_function(Oid opno, Oid *cmpfunc, bool *reverse)
+get_compare_function_for_ordering_op(Oid opno, Oid *cmpfunc, bool *reverse)
{
bool result = false;
CatCList *catlist;
return result;
}
+/*
+ * get_equality_op_for_ordering_op
+ * Get the OID of the datatype-specific btree equality operator
+ * associated with an ordering operator (a "<" or ">" operator).
+ *
+ * Returns InvalidOid if no matching equality operator can be found.
+ * (This indicates that the operator is not a valid ordering operator.)
+ */
+Oid
+get_equality_op_for_ordering_op(Oid opno)
+{
+ Oid result = InvalidOid;
+ CatCList *catlist;
+ int i;
+
+ /*
+ * Search pg_amop to see if the target operator is registered as the "<"
+ * or ">" operator of any btree opfamily. This is exactly like
+ * get_compare_function_for_ordering_op except we don't care whether the
+ * ordering op is "<" or ">" ... the equality operator will be the same
+ * either way.
+ */
+ catlist = SearchSysCacheList(AMOPOPID, 1,
+ ObjectIdGetDatum(opno),
+ 0, 0, 0);
+
+ for (i = 0; i < catlist->n_members; i++)
+ {
+ HeapTuple tuple = &catlist->members[i]->tuple;
+ Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
+
+ /* must be btree */
+ if (aform->amopmethod != BTREE_AM_OID)
+ continue;
+
+ if (aform->amopstrategy == BTLessStrategyNumber ||
+ aform->amopstrategy == BTGreaterStrategyNumber)
+ {
+ /* Found a suitable opfamily, get matching equality operator */
+ result = get_opfamily_member(aform->amopfamily,
+ aform->amoplefttype,
+ aform->amoprighttype,
+ BTEqualStrategyNumber);
+ if (OidIsValid(result))
+ break;
+ /* failure probably shouldn't happen, but keep looking if so */
+ }
+ }
+
+ ReleaseSysCacheList(catlist);
+
+ return result;
+}
+
+/*
+ * get_ordering_op_for_equality_op
+ * Get the OID of a datatype-specific btree ordering operator
+ * associated with an equality operator. (If there are multiple
+ * possibilities, assume any one will do.)
+ *
+ * This function is used when we have to sort data before unique-ifying,
+ * and don't much care which sorting op is used as long as it's compatible
+ * with the intended equality operator. Since we need a sorting operator,
+ * it should be single-data-type even if the given operator is cross-type.
+ * The caller specifies whether to find an op for the LHS or RHS data type.
+ *
+ * Returns InvalidOid if no matching ordering operator can be found.
+ */
+Oid
+get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type)
+{
+ Oid result = InvalidOid;
+ CatCList *catlist;
+ int i;
+
+ /*
+ * Search pg_amop to see if the target operator is registered as the "="
+ * operator of any btree opfamily.
+ */
+ catlist = SearchSysCacheList(AMOPOPID, 1,
+ ObjectIdGetDatum(opno),
+ 0, 0, 0);
+
+ for (i = 0; i < catlist->n_members; i++)
+ {
+ HeapTuple tuple = &catlist->members[i]->tuple;
+ Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
+
+ /* must be btree */
+ if (aform->amopmethod != BTREE_AM_OID)
+ continue;
+
+ if (aform->amopstrategy == BTEqualStrategyNumber)
+ {
+ /* Found a suitable opfamily, get matching ordering operator */
+ Oid typid;
+
+ typid = use_lhs_type ? aform->amoplefttype : aform->amoprighttype;
+ result = get_opfamily_member(aform->amopfamily,
+ typid, typid,
+ BTLessStrategyNumber);
+ if (OidIsValid(result))
+ break;
+ /* failure probably shouldn't happen, but keep looking if so */
+ }
+ }
+
+ ReleaseSysCacheList(catlist);
+
+ return result;
+}
+
+/*
+ * get_compatible_hash_operator
+ * Get the OID of a hash equality operator compatible with the given
+ * operator, but operating on its LHS or RHS datatype as specified.
+ *
+ * If the given operator is not cross-type, the result should be the same
+ * operator, but in cross-type situations it is different.
+ *
+ * Returns InvalidOid if no compatible operator can be found. (This indicates
+ * that the operator should not have been marked oprcanhash.)
+ */
+Oid
+get_compatible_hash_operator(Oid opno, bool use_lhs_type)
+{
+ Oid result = InvalidOid;
+ CatCList *catlist;
+ int i;
+
+ /*
+ * Search pg_amop to see if the target operator is registered as the "="
+ * operator of any hash opfamily. If the operator is registered in
+ * multiple opfamilies, assume we can use any one.
+ */
+ catlist = SearchSysCacheList(AMOPOPID, 1,
+ ObjectIdGetDatum(opno),
+ 0, 0, 0);
+
+ for (i = 0; i < catlist->n_members; i++)
+ {
+ HeapTuple tuple = &catlist->members[i]->tuple;
+ Form_pg_amop aform = (Form_pg_amop) GETSTRUCT(tuple);
+
+ if (aform->amopmethod == HASH_AM_OID &&
+ aform->amopstrategy == HTEqualStrategyNumber)
+ {
+ /* Found a suitable opfamily, get matching single-type operator */
+ Oid typid;
+
+ /* No extra lookup needed if given operator is single-type */
+ if (aform->amoplefttype == aform->amoprighttype)
+ {
+ result = opno;
+ break;
+ }
+ typid = use_lhs_type ? aform->amoplefttype : aform->amoprighttype;
+ result = get_opfamily_member(aform->amopfamily,
+ typid, typid,
+ HTEqualStrategyNumber);
+ if (OidIsValid(result))
+ break;
+ /* failure probably shouldn't happen, but keep looking if so */
+ }
+ }
+
+ ReleaseSysCacheList(catlist);
+
+ return result;
+}
+
/*
* get_op_hash_function
* Get the OID of the datatype-specific hash function associated with
ReleaseSysCacheList(catlist);
}
+/*
+ * ops_in_same_btree_opfamily
+ * Return TRUE if there exists a btree opfamily containing both operators.
+ * (This implies that they have compatible notions of equality.)
+ */
+bool
+ops_in_same_btree_opfamily(Oid opno1, Oid opno2)
+{
+ bool result = false;
+ CatCList *catlist;
+ int i;
+
+ /*
+ * We search through all the pg_amop entries for opno1.
+ */
+ catlist = SearchSysCacheList(AMOPOPID, 1,
+ ObjectIdGetDatum(opno1),
+ 0, 0, 0);
+ 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);
+
+ /* must be btree */
+ if (op_form->amopmethod != BTREE_AM_OID)
+ continue;
+
+ if (op_in_opfamily(opno2, op_form->amopfamily))
+ {
+ result = true;
+ break;
+ }
+ }
+
+ ReleaseSysCacheList(catlist);
+
+ return result;
+}
+
/* ---------- AMPROC CACHES ---------- */
projects / postgresql / blobdiff