Summary:
Hello and thanks for RocksDB,
Here is a PR to add file deletes, renames and ```Flush()```, ```Sync()```, ```Fsync()``` and ```Close()``` to file ops report.
The reason is to help tune RocksDB options when using an env/filesystem with high latencies for file level ("metadata") operations, typically seen during ```DB::Open``` (```db_bench -num 0``` also see https://github.com/facebook/rocksdb/pull/7203 where IOTracing does not trace ```DB::Open```).
Before:
```
> db_bench -benchmarks updaterandom -num 0 -report_file_operations true
...
Entries: 0
...
Num files opened: 12
Num Read(): 6
Num Append(): 8
Num bytes read: 6216
Num bytes written: 6289
```
After:
```
> db_bench -benchmarks updaterandom -num 0 -report_file_operations true
...
Entries: 0
...
Num files opened: 12
Num files deleted: 3
Num files renamed: 4
Num Flush(): 10
Num Sync(): 5
Num Fsync(): 1
Num Close(): 2
Num Read(): 6
Num Append(): 8
Num bytes read: 6216
Num bytes written: 6289
```
Before:
```
> db_bench -benchmarks updaterandom -report_file_operations true
...
Entries: 1000000
...
Num files opened: 18
Num Read(): 396339
Num Append(): 1000058
Num bytes read: 892030224
Num bytes written: 187569238
```
After:
```
> db_bench -benchmarks updaterandom -report_file_operations true
...
Entries: 1000000
...
Num files opened: 18
Num files deleted: 5
Num files renamed: 4
Num Flush(): 1000068
Num Sync(): 9
Num Fsync(): 1
Num Close(): 6
Num Read(): 396339
Num Append(): 1000058
Num bytes read: 892030224
Num bytes written: 187569238
```
Another example showing how using ```DB::OpenForReadOnly``` reduces file operations compared to ```((Optimistic)Transaction)DB::Open```:
```
> db_bench -benchmarks updaterandom -num 1
> db_bench -benchmarks updaterandom -num 0 -use_existing_db true -readonly true -report_file_operations true
...
Entries: 0
...
Num files opened: 8
Num files deleted: 0
Num files renamed: 0
Num Flush(): 0
Num Sync(): 0
Num Fsync(): 0
Num Close(): 0
Num Read(): 13
Num Append(): 0
Num bytes read: 374
Num bytes written: 0
```
```
> db_bench -benchmarks updaterandom -num 1
> db_bench -benchmarks updaterandom -num 0 -use_existing_db true -report_file_operations true
...
Entries: 0
...
Num files opened: 14
Num files deleted: 3
Num files renamed: 4
Num Flush(): 14
Num Sync(): 5
Num Fsync(): 1
Num Close(): 3
Num Read(): 11
Num Append(): 10
Num bytes read: 7291
Num bytes written: 7357
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/8448
Reviewed By: anand1976
Differential Revision: D29333818
Pulled By: zhichao-cao
fbshipit-source-id: a06a8c87f799806462319115195b3e94faf5f542
75741eb0ce