New `--storage` flag switches keeper-bench into an in-process mode that exercises
`KeeperStorage` directly, without the rest of the keeper server (no network, no
raft, no state machine).
Threading model mirrors a simplified Keeper commit path:
* N generator threads (`--concurrency`, default 4) produce requests using the
existing `Generator` (so `setup` + `generator` config is reused).
* One "preprocess" thread calls `preprocessRequest` for every write (stands in
for the path that, in real keeper, runs under `raft_server::lock_`).
* One "commit" thread calls `processRequest` for writes. After each committed
write, with probability `1/writes_per_read_batch` it drains the pending read
queue and processes it in one `processLocalRequests` batch.
Inter-thread queues are `NonblockingBoundedQueue` (copied from commit
6a91c30115) with 100µs polling — no condition
variables. The preprocess->commit queue has a small configurable bound
(`storage.preprocess_commit_queue_size`, default 32).
Periodic reports include (for the period): committed writes/s and reads/s,
preprocess / commit-write / commit-read thread utilization, znode count, RSS,
snapshot-mode flag, and per-op-num average preprocess/process ns and ns-per-
list-name.
Every `storage.snapshot_toggle_periods` periods the runner toggles
`enableSnapshotMode`/`disableSnapshotMode` + `clearGarbageAfterSnapshot`, so the
snapshot overhead shows up in the timings.
Refactoring: `Generator`/`PathGetter` previously took a `Coordination::ZooKeeper
&` to resolve `children_of` paths. They now take a `ListChildrenFn` callback;
the existing Runner passes a lambda wrapping the ZooKeeper client, the new
StorageRunner passes a lambda that calls `KeeperStorage::processLocalRequests`.
Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>
Add `static` to file-local functions and forward declarations
for cross-TU functions to satisfy `-Wmissing-prototypes`.
This ensures all functions have visible prototypes before their
definitions, improving code quality and catching accidental
linkage issues.
Reference: https://github.com/ClickHouse/ClickHouse/issues/76944
Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>
zooqueen