SegmentIterator:
- FileCache: 0ns
- BytesScannedFromCache: 7.06 MB
- BytesScannedFromPeer: 0.00
- BytesScannedFromRemote: 7.80 MB
- BytesWriteIntoCache: 256.00 MB
- CacheGetOrSetTimer: 5.5ms
- GetTimer: 1.463ms
- InvertedIndexBytesScannedFromCache: 0.00
- InvertedIndexBytesScannedFromPeer: 0.00
- InvertedIndexBytesScannedFromRemote: 0.00
- InvertedIndexIOTimer: 0ns
- InvertedIndexLocalIOUseTimer: 0ns
- InvertedIndexNumLocalIOTotal: 0
- InvertedIndexNumPeerIOTotal: 0
- InvertedIndexNumRemoteIOTotal: 0
- InvertedIndexPeerIOUseTimer: 0ns
- InvertedIndexRemoteIOUseTimer: 0ns
- LocalIOUseTimer: 8.644ms
- LockWaitTimer: 107.59us
- NumLocalIOTotal: 206
- NumPeerIOTotal: 0
- NumRemoteIOTotal: 243
- NumSkipCacheIOTotal: 0
- PeerIOUseTimer: 0ns
- ReadCacheFileDirectlyTimer: 0ns
- RemoteIOUseTimer: 20sec903ms
- SetTimer: 1.752ms
- WaitOtherDownloaderTimer: 0ns
- WriteCacheIOUseTimer: 283.851ms
如上Profile, 笔者发现只要查询中BytesScannedFromRemote大于0,查询便会非常慢,笔者的FileCache用的是云磁盘,S3存储用的是云上对象存储,请求时延都在毫秒级,且S3存储的带宽上限非常大(实际带宽利用率不到10%) , 但是表现出来的性能和FileCache差异在1000倍以上, 7MB云磁盘FileCache上的数据8毫秒读完,7MB S3上的数据花了20秒读完, 这个差异和预期相差太远了
社区大佬能帮分析下可能的原因吗,如果差异真的这么大, 那感觉远端S3存储的性能几乎不可用了
另外笔者让云上S3存储的同学看了日志, 单次请求的耗时基本上都在50毫秒左右,S3本身的性能应该是没有问题的
