云原生数据仓库AnalyticDB PostgreSQL版能否导出时到oss上是一个合并好的文件？

云原生数据仓库AnalyticDB使用upload命令导出csv到oss上，能否导出时到oss上是一个合并好的文件，而不是多个分片文件？https://help.aliyun.com/document_detail/186271.html?spm=a2c4g.35457.0.i5#961b7a9d16jcqUNLOAD ('SELECT FROM test')
TO 'oss://adbpg-regress/local_t/'
ACCESS_KEY_ID 'LTAI5tDfyHVmxCf66Un*'
SECRET_ACCESS_KEY 'TNPPxOFY4xx7CZGjVgSsVBtIs'
FORMAT csv
"delimiter" '|'
"quote" '"'
"null" ''
"header" 'true'
"escape" 'E'
"encoding" 'utf-8'
FDW 'oss_fdw'
ENDPOINT 'oss-cn-hangzhou-internal.aliyuncs.com';