Add AsyncDbWorker: a persistent background thread with dedup queue that
executes DB2 writes asynchronously, keeping the mon 20ms cycle free of
blocking I/O.
Changes:
- async_db_worker.h/.cc: singleton worker, submit() with rule_id dedup,
drain_and_stop() for clean shutdown
- eqp_stat.h/.cc: new update_static(ruleid, shear_times, running_time)
overload that skips redundant DB reads for known values (reduces
5 SELECTs to 3 per persist cycle)
- exp_times.cc: extract persist_exp_times() as a standalone function,
update_history_times() snapshots values and submits to worker
(returns immediately), reset_dev_data() uses direct SHM update
- eqpalg_icei.cpp: alg_mgr_.reset() → drain_and_stop() in destructor
ensures all algorithm threads are stopped before draining the worker
Risk: re-run cmake .. to pick up the new async_db_worker.cc file.
DataRecord used a fixed float[129600000] consuming 5GB disk even when
collecting only a few hundred data points. Replaced with shm_vector_f
that grows on demand via push_back. Removes the need for rm -rf on
process exit — vector destructor frees memory back to the segment.
Also drops now-unnecessary task_data_size member.
The workaround was needed because bipc::string items in shared memory would
segfault on restart when tag names exceeded SSO length. Now that display
data (items, etc.) lives in local-memory DisplayCache and only cold doubles
remain in shared memory, the dangling-allocator bug no longer exists.
Deleting the file also broke mon-cron IPC across restarts.
