diff --git a/contrib/bench/README.md b/contrib/bench/README.md
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+# Chain DB benchmark harness
+
+Measures `FastImportBlockFile()` speed under each chain-DB backend
+(LevelDB vs RocksDB) using a user-supplied `blk0001.dat` block stream.
+
+## Prerequisites
+
+- A `trianglesd` binary built with both backends:
+  ```
+  cmake -B build -G Ninja \
+      -DCMAKE_BUILD_TYPE=Release \
+      -DBUILD_QT=OFF \
+      -DBUILD_DAEMON=ON \
+      -DBUILD_ROCKSDB=ON
+  cmake --build build
+  ```
+- An `blk0001.dat` file (old-style block stream). If you have a synced
+  node, copy `~/.triangles/blk0001.dat` (Linux) or `%APPDATA%\triangles\blk0001.dat` (Windows).
+- Free disk space: ~3× the size of `blk0001.dat` per backend run
+  (raw blocks + chain DB index + working space).
+
+## Usage
+
+```bash
+contrib/bench/bench-chaindb.sh \
+  --binary=$(pwd)/build/bin/trianglesd \
+  --bootstrap=/path/to/blk0001.dat
+```
+
+Runs each backend in turn, appends a CSV row to `./bench-results.csv`,
+and prints a summary to stdout. Default `--dbcache=2048` (MB).
+
+### Options
+
+| Flag | Default | Notes |
+| --- | --- | --- |
+| `--binary=PATH` | (required) | Path to `trianglesd` |
+| `--bootstrap=PATH` | (required) | Path to `blk0001.dat` |
+| `--backends=LIST` | `leveldb,rocksdb` | Comma-separated subset |
+| `--workdir=DIR` | `/tmp/triangles-bench-XXXXXX` | Per-backend datadirs go here |
+| `--dbcache=MB` | `2048` | Chain DB cache size |
+| `--results-csv=FILE` | `./bench-results.csv` | Appended to |
+| `--keep-datadirs` | off | Preserve datadirs after run for inspection |
+| `--rpc-port=BASE` | `19112` | Each backend uses `BASE+offset` |
+
+## What it measures
+
+| Column | Source |
+| --- | --- |
+| `wall_ms` | The daemon's own log line: `FastImportBlockFile: indexed N blocks in Mms` |
+| `peak_rss_kb` | `ps -o rss=` sampled once per second |
+| `datadir_bytes` | `du -sb` of the working datadir (includes `blk0001.dat`) |
+| `blocks_indexed` | Parsed from the same log line |
+
+## What it does not measure
+
+- Network IBD (peer fetch, header sync) — this is pure DB ingest.
+- UTXO snapshot load — `LoadSnapshot` is currently rocksdb-guarded
+  (see `src/utxosnapshot.cpp`); will be unblocked when LevelDB is retired.
+- Reorg cost — separate test, not yet implemented.
+- Disk I/O bytes (read/written) — could be added with `iostat` integration.
+
+## Interpreting results
+
+A meaningful comparison requires both rows to have run on the same machine
+with the same `blk0001.dat`. The `host` column makes mixing runs across
+machines visible in the CSV.
+
+Backend-relevant size comparisons should subtract `bootstrap_size_bytes`
+from `datadir_bytes` to isolate the chain DB tree.
+
+## One-liners
+
+```bash
+# LevelDB only
+./bench-chaindb.sh --binary=... --bootstrap=... --backends=leveldb
+
+# Compare 2GB vs 4GB cache on RocksDB
+./bench-chaindb.sh --binary=... --bootstrap=... --backends=rocksdb --dbcache=2048
+./bench-chaindb.sh --binary=... --bootstrap=... --backends=rocksdb --dbcache=4096
+
+# Keep the datadirs for poking around afterwards
+./bench-chaindb.sh --binary=... --bootstrap=... --keep-datadirs
+```
diff --git a/contrib/bench/bench-chaindb.sh b/contrib/bench/bench-chaindb.sh
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+#!/usr/bin/env bash
+# Benchmark FastImportBlockFile() speed across chain-DB backends.
+#
+# Reads a user-supplied blk0001.dat (old-style block stream) and times the
+# full block-index rebuild under each backend. Output: a CSV row per backend
+# with wall time, peak RSS, and resulting datadir size on disk.
+#
+# Usage:
+#   ./bench-chaindb.sh \
+#     --binary=/path/to/trianglesd \
+#     --bootstrap=/path/to/blk0001.dat \
+#     [--backends=leveldb,rocksdb]       default: both
+#     [--workdir=/tmp/triangles-bench]   parent dir for per-backend datadirs
+#     [--dbcache=2048]                   in MB
+#     [--results-csv=./bench-results.csv]
+#     [--keep-datadirs]                  preserve datadirs after run
+#     [--rpc-port=BASE]                  default 19112; each run uses BASE+offset
+#
+# Notes:
+#   - The binary must be built with BUILD_ROCKSDB=ON when --backends includes rocksdb.
+#   - This script does not assume Tor is configured. It launches with -nolisten
+#     and -connect=0 to keep the run network-isolated.
+#   - Wall time comes from the daemon's own perf log line:
+#         "FastImportBlockFile: indexed N blocks in Mms"
+#   - Peak RSS is sampled via `ps -o rss=` once a second.
+
+set -euo pipefail
+
+# ── Defaults ────────────────────────────────────────────────────────────────
+BINARY=""
+BOOTSTRAP=""
+BACKENDS="leveldb,rocksdb"
+WORKDIR=""
+DBCACHE=2048
+RESULTS_CSV="./bench-results.csv"
+KEEP=0
+RPC_BASE=19112
+
+# ── Arg parsing ─────────────────────────────────────────────────────────────
+for arg in "$@"; do
+    case "$arg" in
+        --binary=*)         BINARY="${arg#*=}" ;;
+        --bootstrap=*)      BOOTSTRAP="${arg#*=}" ;;
+        --backends=*)       BACKENDS="${arg#*=}" ;;
+        --workdir=*)        WORKDIR="${arg#*=}" ;;
+        --dbcache=*)        DBCACHE="${arg#*=}" ;;
+        --results-csv=*)    RESULTS_CSV="${arg#*=}" ;;
+        --keep-datadirs)    KEEP=1 ;;
+        --rpc-port=*)       RPC_BASE="${arg#*=}" ;;
+        -h|--help)
+            sed -n '2,28p' "$0" | sed 's/^# \?//'
+            exit 0 ;;
+        *)
+            echo "Unknown argument: $arg" >&2
+            exit 2 ;;
+    esac
+done
+
+[ -n "$BINARY" ]    || { echo "--binary is required" >&2; exit 2; }
+[ -n "$BOOTSTRAP" ] || { echo "--bootstrap is required" >&2; exit 2; }
+[ -x "$BINARY" ]    || { echo "Binary not executable: $BINARY" >&2; exit 2; }
+[ -f "$BOOTSTRAP" ] || { echo "Bootstrap file not found: $BOOTSTRAP" >&2; exit 2; }
+
+if [ -z "$WORKDIR" ]; then
+    WORKDIR="$(mktemp -d -t triangles-bench-XXXXXX)"
+fi
+mkdir -p "$WORKDIR"
+echo "Workdir: $WORKDIR"
+
+# ── CSV header (only if file is new) ───────────────────────────────────────
+if [ ! -f "$RESULTS_CSV" ]; then
+    echo "timestamp,backend,bootstrap_size_bytes,dbcache_mb,blocks_indexed,wall_ms,peak_rss_kb,datadir_bytes,binary,host" > "$RESULTS_CSV"
+fi
+
+bootstrap_size="$(stat -c%s "$BOOTSTRAP" 2>/dev/null || stat -f%z "$BOOTSTRAP")"
+host="$(hostname)"
+ts_run="$(date -u +%Y-%m-%dT%H:%M:%SZ)"
+
+# ── Per-backend run ─────────────────────────────────────────────────────────
+run_backend() {
+    local backend="$1"
+    local idx="$2"
+    local datadir="$WORKDIR/$backend"
+    local rpc_port=$((RPC_BASE + idx))
+    local rss_log="$WORKDIR/$backend.rss.log"
+
+    echo
+    echo "════════════════════════════════════════════════════════════════════"
+    echo "  Backend: $backend  (datadir: $datadir, rpcport: $rpc_port)"
+    echo "════════════════════════════════════════════════════════════════════"
+
+    # Fresh datadir, copy bootstrap into place. FastImportBlockFile() picks
+    # this up automatically when the block index is empty.
+    rm -rf "$datadir"
+    mkdir -p "$datadir"
+    cp "$BOOTSTRAP" "$datadir/blk0001.dat"
+
+    # Minimal config — disable network so we measure only the import path.
+    cat > "$datadir/triangles.conf" <<EOF
+chaindb=$backend
+dbcache=$DBCACHE
+nolisten=1
+connect=0
+rpcuser=bench
+rpcpassword=bench
+rpcport=$rpc_port
+debug=1
+printtoconsole=0
+EOF
+
+    # Launch in background. -daemon would daemonize but we want to track the
+    # process tree; run in foreground and background it ourselves so we keep
+    # the PID for RSS sampling and clean shutdown.
+    local pid
+    "$BINARY" -datadir="$datadir" -conf="triangles.conf" >"$datadir/stdout.log" 2>&1 &
+    pid=$!
+    echo "Launched $backend (pid $pid)"
+
+    # RSS sampler: log peak every second to a file.
+    (
+        while kill -0 "$pid" 2>/dev/null; do
+            ps -o rss= -p "$pid" 2>/dev/null | tr -d ' ' >> "$rss_log" || true
+            sleep 1
+        done
+    ) &
+    local sampler_pid=$!
+
+    # Watch for "FastImportBlockFile: indexed N blocks in Mms" in the daemon's
+    # debug.log, which is the deterministic completion signal.
+    local debug_log="$datadir/debug.log"
+    local wait_start
+    wait_start="$(date +%s)"
+    local timeout_s=86400  # 24 hours hard cap
+    local indexed_line=""
+    while :; do
+        if [ -f "$debug_log" ]; then
+            indexed_line="$(grep -E "FastImportBlockFile: indexed [0-9]+ blocks in [0-9]+ms" "$debug_log" | tail -1 || true)"
+            if [ -n "$indexed_line" ]; then
+                break
+            fi
+        fi
+        if ! kill -0 "$pid" 2>/dev/null; then
+            echo "Daemon exited before completion line appeared. Check $datadir/stdout.log" >&2
+            kill "$sampler_pid" 2>/dev/null || true
+            return 1
+        fi
+        local elapsed=$(( $(date +%s) - wait_start ))
+        if [ "$elapsed" -gt "$timeout_s" ]; then
+            echo "Timeout after ${timeout_s}s without completion line" >&2
+            kill "$pid" 2>/dev/null || true
+            kill "$sampler_pid" 2>/dev/null || true
+            return 1
+        fi
+        sleep 5
+    done
+
+    echo "Completion: $indexed_line"
+
+    # Parse blocks_indexed and wall_ms from the line.
+    local blocks_indexed wall_ms
+    blocks_indexed="$(echo "$indexed_line" | sed -E 's/.*indexed ([0-9]+) blocks.*/\1/')"
+    wall_ms="$(echo "$indexed_line" | sed -E 's/.*in ([0-9]+)ms.*/\1/')"
+
+    # Stop daemon cleanly via RPC, fall back to SIGTERM.
+    "$BINARY" -datadir="$datadir" -conf="triangles.conf" stop >/dev/null 2>&1 || \
+        kill -TERM "$pid" 2>/dev/null || true
+
+    # Wait up to 60s for clean exit.
+    local stop_wait=0
+    while kill -0 "$pid" 2>/dev/null && [ "$stop_wait" -lt 60 ]; do
+        sleep 1
+        stop_wait=$((stop_wait + 1))
+    done
+    kill -KILL "$pid" 2>/dev/null || true
+    wait "$sampler_pid" 2>/dev/null || true
+
+    # Peak RSS: max of the sampler's recorded values.
+    local peak_rss_kb=0
+    if [ -f "$rss_log" ] && [ -s "$rss_log" ]; then
+        peak_rss_kb="$(sort -nr "$rss_log" | head -1)"
+    fi
+
+    # Datadir size — separate the chain DB from blk0001.dat (which is ~constant
+    # across backends). We report the total datadir size; the consumer can
+    # subtract bootstrap_size_bytes if they want chain-DB-only.
+    local datadir_bytes
+    datadir_bytes="$(du -sb "$datadir" 2>/dev/null | awk '{print $1}' || du -sk "$datadir" | awk '{print $1*1024}')"
+
+    # Append CSV row.
+    echo "$ts_run,$backend,$bootstrap_size,$DBCACHE,$blocks_indexed,$wall_ms,$peak_rss_kb,$datadir_bytes,$BINARY,$host" >> "$RESULTS_CSV"
+
+    # Stdout summary.
+    printf "  blocks indexed: %s\n" "$blocks_indexed"
+    printf "  wall time:      %s ms (%.1f min)\n" "$wall_ms" "$(awk "BEGIN{print $wall_ms/60000}")"
+    printf "  peak RSS:       %s KB (%.1f GB)\n" "$peak_rss_kb" "$(awk "BEGIN{print $peak_rss_kb/1024/1024}")"
+    printf "  datadir size:   %s bytes (%.1f GB)\n" "$datadir_bytes" "$(awk "BEGIN{print $datadir_bytes/1024/1024/1024}")"
+
+    # Cleanup unless --keep-datadirs.
+    if [ "$KEEP" -eq 0 ]; then
+        rm -rf "$datadir"
+    fi
+}
+
+# ── Main loop ──────────────────────────────────────────────────────────────
+idx=0
+IFS=',' read -r -a backends_arr <<< "$BACKENDS"
+for backend in "${backends_arr[@]}"; do
+    case "$backend" in
+        leveldb|rocksdb) ;;
+        *) echo "Unknown backend: $backend" >&2; exit 2 ;;
+    esac
+    run_backend "$backend" "$idx"
+    idx=$((idx + 1))
+done
+
+echo
+echo "Done. Results appended to $RESULTS_CSV"