Oid
index_create(Relation heapRelation,
			 const char *indexRelationName,
			 Oid indexRelationId,
			 Oid parentIndexRelid,
			 Oid parentConstraintId,
			 RelFileNumber relFileNumber,
			 IndexInfo *indexInfo,
			 List *indexColNames,
			 Oid accessMethodObjectId,
			 Oid tableSpaceId,
			 Oid *collationObjectId,
			 Oid *classObjectId,
			 int16 *coloptions,
			 Datum reloptions,
			 bits16 flags,
			 bits16 constr_flags,
			 bool allow_system_table_mods,
			 bool is_internal,
			 Oid *constraintId)

	/*
	 * The index will be in the same namespace as its parent table, and is
	 * shared across databases if and only if the parent is.  Likewise, it
	 * will use the relfilenumber map if and only if the parent does; and it
	 * inherits the parent's relpersistence.
	 */
	namespaceId = RelationGetNamespace(heapRelation);
	shared_relation = heapRelation->rd_rel->relisshared;
	mapped_relation = RelationIsMapped(heapRelation);
	relpersistence = heapRelation->rd_rel->relpersistence;

	/*
	 * Btree text_pattern_ops uses text_eq as the equality operator, which is
	 * fine as long as the collation is deterministic; text_eq then reduces to
	 * bitwise equality and so it is semantically compatible with the other
	 * operators and functions in that opclass.  But with a nondeterministic
	 * collation, text_eq could yield results that are incompatible with the
	 * actual behavior of the index (which is determined by the opclass's
	 * comparison function).  We prevent such problems by refusing creation of
	 * an index with that opclass and a nondeterministic collation.
	 *
	 * The same applies to varchar_pattern_ops and bpchar_pattern_ops.  If we
	 * find more cases, we might decide to create a real mechanism for marking
	 * opclasses as incompatible with nondeterminism; but for now, this small
	 * hack suffices.
	 *
	 * Another solution is to use a special operator, not text_eq, as the
	 * equality opclass member; but that is undesirable because it would
	 * prevent index usage in many queries that work fine today.
	 */
	for (i = 0; i < indexInfo->ii_NumIndexKeyAttrs; i++)
	{
		Oid			collation = collationObjectId[i];
		Oid			opclass = classObjectId[i];

		if (collation)
		{
			if ((opclass == TEXT_BTREE_PATTERN_OPS_OID ||
				 opclass == VARCHAR_BTREE_PATTERN_OPS_OID ||
				 opclass == BPCHAR_BTREE_PATTERN_OPS_OID) &&
				!get_collation_isdeterministic(collation))
			{
				HeapTuple	classtup;

				classtup = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclass));
				if (!HeapTupleIsValid(classtup))
					elog(ERROR, "cache lookup failed for operator class %u", opclass);
				ereport(ERROR,
						(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
						 errmsg("nondeterministic collations are not supported for operator class \"%s\"",
								NameStr(((Form_pg_opclass) GETSTRUCT(classtup))->opcname))));
				ReleaseSysCache(classtup);
			}
		}
	}

	/*
	 * Concurrent index build on a system catalog is unsafe because we tend to
	 * release locks before committing in catalogs.
	 */
	if (concurrent &&
		IsCatalogRelation(heapRelation))
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("concurrent index creation on system catalog tables is not supported")));

	/*
	 * This case is currently not supported.  There's no way to ask for it in
	 * the grammar with CREATE INDEX, but it can happen with REINDEX.
	 */
	if (concurrent && is_exclusion)
		ereport(ERROR,
				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
				 errmsg("concurrent index creation for exclusion constraints is not supported")));

	/*
	 * We cannot allow indexing a shared relation after initdb (because
	 * there's no way to make the entry in other databases' pg_class).
	 */
	if (shared_relation && !IsBootstrapProcessingMode())
		ereport(ERROR,
				(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
				 errmsg("shared indexes cannot be created after initdb")));

	/*
	 * Check for duplicate name (both as to the index, and as to the
	 * associated constraint if any).  Such cases would fail on the relevant
	 * catalogs' unique indexes anyway, but we prefer to give a friendlier
	 * error message.
	 */
	if (get_relname_relid(indexRelationName, namespaceId))
	{
		if ((flags & INDEX_CREATE_IF_NOT_EXISTS) != 0)
		{
			ereport(NOTICE,
					(errcode(ERRCODE_DUPLICATE_TABLE),
					 errmsg("relation \"%s\" already exists, skipping",
							indexRelationName)));
			table_close(pg_class, RowExclusiveLock);
			return InvalidOid;
		}

		ereport(ERROR,
				(errcode(ERRCODE_DUPLICATE_TABLE),
				 errmsg("relation \"%s\" already exists",
						indexRelationName)));
	}

	if ((flags & INDEX_CREATE_ADD_CONSTRAINT) != 0 &&
		ConstraintNameIsUsed(CONSTRAINT_RELATION, heapRelationId,
							 indexRelationName))
	{
		/*
		 * INDEX_CREATE_IF_NOT_EXISTS does not apply here, since the
		 * conflicting constraint is not an index.
		 */
		ereport(ERROR,
				(errcode(ERRCODE_DUPLICATE_OBJECT),
				 errmsg("constraint \"%s\" for relation \"%s\" already exists",
						indexRelationName, RelationGetRelationName(heapRelation))));
	}

	/*
	 * construct tuple descriptor for index tuples
	 */
	indexTupDesc = ConstructTupleDescriptor(heapRelation,
											indexInfo,
											indexColNames,
											accessMethodObjectId,
											collationObjectId,
											classObjectId);

	/*
	 * Allocate an OID for the index, unless we were told what to use.
	 *
	 * The OID will be the relfilenumber as well, so make sure it doesn't
	 * collide with either pg_class OIDs or existing physical files.
	 */
	if (!OidIsValid(indexRelationId))
	{
		/* Use binary-upgrade override for pg_class.oid and relfilenumber */
		if (IsBinaryUpgrade)
		{
			if (!OidIsValid(binary_upgrade_next_index_pg_class_oid))
				ereport(ERROR,
						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
						 errmsg("pg_class index OID value not set when in binary upgrade mode")));

			indexRelationId = binary_upgrade_next_index_pg_class_oid;
			binary_upgrade_next_index_pg_class_oid = InvalidOid;

	/*
	 * create the index relation's relcache entry and, if necessary, the
	 * physical disk file. (If we fail further down, it's the smgr's
	 * responsibility to remove the disk file again, if any.)
	 */
	indexRelation = heap_create(indexRelationName,
								namespaceId,
								tableSpaceId,
								indexRelationId,
								relFileNumber,
								accessMethodObjectId,
								indexTupDesc,
								relkind,
								relpersistence,
								shared_relation,
								mapped_relation,
								allow_system_table_mods,
								&relfrozenxid,
								&relminmxid,
								create_storage);

	/*
	 * store index's pg_class entry
	 */
	InsertPgClassTuple(pg_class, indexRelation,
					   RelationGetRelid(indexRelation),
					   (Datum) 0,
					   reloptions);

	/* done with pg_class */
	table_close(pg_class, RowExclusiveLock);

	/*
	 * now update the object id's of all the attribute tuple forms in the
	 * index relation's tuple descriptor
	 */
	InitializeAttrbuteOids(indexRelation,
							indexInfo->ii_NumIndexAttrs,
							indexRelationId);

	/*
	 * append ATTRIBUTE tuples for the index
	 */
	AppendAttributeTuples(indexRelation, indexInfo->ii_OpclassOptions);

	/* ----------------
	 *	  update pg_index
	 *	  (append INDEX tuple)
	 *
	 *	  Note that this stows away a representation of "predicate".
	 *	  (Or, could define a rule to maintain the predicate) --Nels, Feb '92
	 * ----------------
	 */
	UpdateIndexRelation(indexRelationId, heapRelationId, parentIndexRelid,
						indexInfo,
						collationObjectId, classObjectId, coloptions,
						isprimary, is_exclusion,
						(constr_flags & INDEX_CONSTR_CREATE_DEFERRABLE) == 0,
						!concurrent && !invalid,
						!concurrent);

	/*
	 * Register constraint and dependencies for the index.
	 *
	 * If the index is from a CONSTRAINT clause, construct a pg_constraint
	 * entry.  The index will be linked to the constraint, which in turn is
	 * linked to the table.  If it's not a CONSTRAINT, we need to make a
	 * dependency directly on the table.
	 *
	 * We don't need a dependency on the namespace, because there'll be an
	 * indirect dependency via our parent table.
	 *
	 * During bootstrap we can't register any dependencies, and we don't try
	 * to make a constraint either.
	 */
	if (!IsBootstrapProcessingMode())
	{
		ObjectAddress myself,
					referenced;
		ObjectAddresses *addrs;

		ObjectAddressSet(myself, RelationRelationId, indexRelationId);

		if ((flags & INDEX_CREATE_ADD_CONSTRAINT) != 0)
		{
			char		constraintType;
			ObjectAddress localaddr;
			...

	/*
	 * If this is bootstrap (initdb) time, then we don't actually fill in the
	 * index yet.  We'll be creating more indexes and classes later, so we
	 * delay filling them in until just before we're done with bootstrapping.
	 * Similarly, if the caller specified to skip the build then filling the
	 * index is delayed till later (ALTER TABLE can save work in some cases
	 * with this).  Otherwise, we call the AM routine that constructs the
	 * index.
	 */
	if (IsBootstrapProcessingMode())
	{
		index_register(heapRelationId, indexRelationId, indexInfo);
	}
	else if ((flags & INDEX_CREATE_SKIP_BUILD) != 0)
	{
		/*
		 * Caller is responsible for filling the index later on.  However,
		 * we'd better make sure that the heap relation is correctly marked as
		 * having an index.
		 */
		index_update_stats(heapRelation,
						   true,
						   -1.0);
		/* Make the above update visible */
		CommandCounterIncrement();
	}
	else
	{
		index_build(heapRelation, indexRelation, indexInfo, false, true);
	}