doris-debug-import

# Import / Group Commit ## async_mode WAL semantics Write WAL → RPC returns → background group commit → **delete_wal** on success (`group_commit_mgr.cpp`). Drain rate = commit finish rate ≠ compaction GB/s. ## Knobs (config.cpp) | Config | Default | Role | |--------|---------|------| | `group_commit_insert_threads` | 10 | commit worker pool | | `group_commit_relay_wal_threads` | 10 | WAL replay | | `group_commit_wal_path` | under storage_root | WAL disks | | `group_commit_wal_max_disk_limit` | 10% | WAL quota | | table `group_commit_data_bytes` | often 64MB | size flush | | table `group_commit_interval_ms` | often 10000 | time flush | ## High MB/s guidance 1. Split load across BEs (WAL is local to coordinator BE). 2. `wal-du` on each BE storage path. 3. Prefer dedicated NVMe for `group_commit_wal_path`. 4. A/B `group_commit_data_bytes` (128MB vs 512MB) — size threshold dominates when ingest ≫ interval. 5. `sync_mode` or client throttle for backpressure. ```bash ./scripts/doris-debug wal-du /path/to/be/storage ./scripts/doris-debug log-grep be/log --pack group_commit ```