Merged pull request https://github.com/scylladb/scylla/pull/6030 from
Piotr Dulikowski:
Adds CDC-related metrics.
Following counters are added, both for total and failed operations:
Total number of CDC operations that did/did not perform splitting,
Total number of CDC operations that touched a particular mutation part.
Total number of preimage selects.
Fixes#6002.
Tests: unit(dev, debug)
* 'cdc-metrics' of github.com:piodul/scylla:
storage_proxy: track CDC operations in LWT flow
storage_proxy: track CDC operations in logged batches
storage_proxy: track CDC operations in standard flow
storage_proxy: add cdc tracker hooks to write response handlers
storage_proxy: move "else if" remainder into "else" block
cdc: create an operation_result_tracker object
cdc: add an object for tracking progress of cdc mutations
cdc: count touched mutation parts in transformer::transform
cdc: track preimage selects in metrics
cdc: register metric counters
cdc: fix non-atomic updates in splitting