The current "CommitsCountPerWriter" stats exposed by SegmentNodeStoreStats are hard to follow since there can be too many writers at a time. To improve this, a more coarse-grained version of this metric should be added, in which commits are recorded for groups of threads. The groups should be configurable and represent regexes to be matched by individual thread names. An additional group (i.e. "other") will group all threads not matching any of the defined group regexes.
The current behaviour will be split in two:
- "CommitsCountOtherThreads" will expose a snapshot of threads currently in "other" group
- "CommitsCountPerGroup" will expose an aggregate of commits count per thread group for the previous minute.
Both metrics will be reset each minute.