Function MakeIndexSpecForBuiltinIdIndex

pg_documentdb/src/metadata/index.c:1228–1257

* MakeIndexSpecForBuiltinIdIndex returns an IndexSpec for a built-in _id index. */

 * MakeIndexSpecForBuiltinIdIndex returns an IndexSpec for a built-in _id index.
 */
IndexSpec
MakeIndexSpecForBuiltinIdIndex(void)
{
	pgbson_writer indexKeyDocumentWriter;
	PgbsonWriterInit(&indexKeyDocumentWriter);
	int idIndexOrdering = 1;
	PgbsonWriterAppendInt32(&indexKeyDocumentWriter, ID_FIELD_KEY,
							strlen(ID_FIELD_KEY), idIndexOrdering);

	IndexSpec idIndexSpec = {
		.indexName = ID_INDEX_NAME,
		.indexVersion = 2,
		.indexKeyDocument = PgbsonWriterGetPgbson(&indexKeyDocumentWriter),
		.indexPFEDocument = NULL,
		.indexWPDocument = NULL,
		.indexSparse = BoolIndexOption_Undefined,

		/*
		 * Even though the _id index is unique, Mongo (and we) report it as
		 * "non unique". This is especially true in Sharded collections where
		 * it's only unique by shard key.
		 */
		.indexUnique = BoolIndexOption_Undefined,
		.indexExpireAfterSeconds = NULL,
		.cosmosSearchOptions = NULL,
		.indexOptions = NULL
	};

	return idIndexSpec;
}


/*