Zhongyi Xie b0259e45e0 add more tracing for stats history (#5566)
Summary:
Sample info log output from db_bench:
In-memory:
```
2019/07/12-21:39:19.478490 7fa01b3f5700 [_impl/db_impl.cc:702] ------- PERSISTING STATS -------
2019/07/12-21:39:19.478633 7fa01b3f5700 [_impl/db_impl.cc:753] Storing 145 stats with timestamp 1562992759 to in-memory stats history
2019/07/12-21:39:19.478670 7fa01b3f5700 [_impl/db_impl.cc:766] [Pre-GC] In-memory stats history size: 1051218 bytes, slice count: 103
2019/07/12-21:39:19.478704 7fa01b3f5700 [_impl/db_impl.cc:775] [Post-GC] In-memory stats history size: 1051218 bytes, slice count: 102
```
On-disk:
```
2019/07/12-21:48:53.862548 7f24943f5700 [_impl/db_impl.cc:702] ------- PERSISTING STATS -------
2019/07/12-21:48:53.862553 7f24943f5700 [_impl/db_impl.cc:709] Reading 145 stats from statistics
2019/07/12-21:48:53.862852 7f24943f5700 [_impl/db_impl.cc:737] Writing 145 stats with timestamp 1562993333 to persistent stats CF succeeded
```
```
2019/07/12-21:48:51.861711 7f24943f5700 [_impl/db_impl.cc:702] ------- PERSISTING STATS -------
2019/07/12-21:48:51.861729 7f24943f5700 [_impl/db_impl.cc:709] Reading 145 stats from statistics
2019/07/12-21:48:51.861921 7f24943f5700 [_impl/db_impl.cc:732] Writing to persistent stats CF failed -- Result incomplete: Write stall
...
2019/07/12-21:48:51.873032 7f2494bf6700 [WARN] [lumn_family.cc:749] [default] Stopping writes because we have 2 immutable memtables (waiting for flush), max_write_buffer_number is set to 2
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5566

Differential Revision: D16258187

Pulled By: miasantreble

fbshipit-source-id: 292497099b941418590ed4312411bee36e244dc5
2019-07-15 11:49:17 -07:00
..
2019-05-31 15:24:43 -07:00