diff --git a/test/coverage/full-run-3/cov-subsystems.txt b/test/coverage/full-run-3/cov-subsystems.txt
new file mode 100644
index 000000000..ad4d9b076
--- /dev/null
+++ b/test/coverage/full-run-3/cov-subsystems.txt
@@ -0,0 +1,23 @@
+ line%    br%    fn%  lines   lhit  branch   bhit    fn fnhit files  subsystem
+  99.3   83.8  100.0    143    142      74     62     8     8     2  hmac
+  85.8   68.6   97.4    829    711     909    624    39    38     6  dbreg
+  83.3   58.8   96.2    891    742     861    506    53    51     7  mutex
+  76.9   51.9   92.6   2799   2152    3748   1946    94    87    11  lock
+  74.6   58.4   79.2   3745   2795    2989   1747   168   133    13  env
+  74.4   47.6   87.7   2190   1630    2758   1312    57    50    11  heap
+  74.4   54.8   83.8   4276   3180    5171   2835   136   114    16  mp
+  73.4   55.4   87.3  10214   7496   12250   6786   245   214    21  btree
+  73.1   60.2   80.0   1141    834    1262    760    40    32     5  fileops
+  71.6   53.5   85.4   2132   1527    2484   1328   103    88    11  txn
+  71.2   48.9   82.2   5427   3865    6518   3186   152   125    16  hash
+  71.1   49.3   83.0   1143    813    1091    538   100    83    39  os
+  70.8   50.8   92.4   2373   1681    2612   1326    66    61    11  qam
+  66.3   49.9   78.8  13880   9201   15809   7882   472   372    38  db
+  64.5   46.0   85.2    753    486     335    154    27    23     5  crypto
+  64.1   38.3   86.4    521    334     596    228    22    19     2  sequence
+  62.2   45.7   68.7   6087   3788    5584   2551   268   184    13  log
+  59.1   43.8   79.2   5334   3150    4156   1822   283   224    13  repmgr
+  58.6   42.0   73.9   7106   4165    8039   3379   207   153    11  rep
+  52.1   48.0   83.3    959    500     554    266    84    70    16  common
+   0.0    0.0    0.0    434      0     436      0    20     0     2  xa
+  68.0   50.2   80.5  72377  49192   78236  39238  2644  2129        TOTAL
diff --git a/test/coverage/full_run3_combined.sh b/test/coverage/full_run3_combined.sh
new file mode 100644
index 000000000..a16c2bcbe
--- /dev/null
+++ b/test/coverage/full_run3_combined.sh
@@ -0,0 +1,231 @@
+#!/usr/bin/env bash
+# full_run3_combined.sh -- AUTHORITATIVE full-suite coverage run.
+# Merges (a) the parallel full Tcl suite (access methods + all subsystem groups
+# + replication + logverify + recd) with (b) every COV_* block from
+# run_coverage.sh (curated subset + XA/upgrade/os_aio/backup/recd_compact C
+# drivers + crypto/stat/mvcc/lock via the curated subset). ONE instrumented
+# build, .gcda accumulated across both phases, ONE lcov capture from .libs.
+# Measurement only -- no engine code touched.
+set -uo pipefail
+R="$HOME/libdb"; B="$R/build_unix"; here="$R/test/coverage"
+TCLBIN=tclsh8.6
+command -v tclsh8.6 >/dev/null 2>&1 || TCLBIN=tclsh
+IGN="mismatch,source,gcov,unused,negative,empty,inconsistent,version"
+AM_CAP=${AM_CAP:-9000}; SUB_CAP=${SUB_CAP:-5400}; REP_CAP=${REP_CAP:-360}; LV_CAP=${LV_CAP:-2400}
+export CC=gcc
+log(){ echo "[$(date -u +%H:%M:%S)] $*"; }
+cd "$B"
+RESULTS=/tmp/cov3-results.txt; : > "$RESULTS"
+DONE=/tmp/cov3-done; rm -f "$DONE"
+T_START=$(date +%s)
+
+# =========================================================================
+# PHASE 0: configure + build ONCE with coverage instrumentation
+# =========================================================================
+log "=== PHASE 0: configure + build (--coverage) ==="
+find "$B" \( -name '*.gcda' -o -name '*.gcno' \) -delete 2>/dev/null || true
+rm -f "$B"/coverage*.info "$B"/cov*-src*.info "$B"/cov-src.info 2>/dev/null || true
+CC=gcc ../dist/configure --enable-debug --enable-test --with-tcl=/usr/lib64 \
+  CFLAGS="-O0 -g --coverage" LDFLAGS="--coverage" >/tmp/cov3-configure.log 2>&1 \
+  || { echo "CONFIGURE FAILED"; tail -30 /tmp/cov3-configure.log; exit 1; }
+make -j"$(nproc)" >/tmp/cov3-build.log 2>&1 \
+  || { echo "BUILD FAILED"; tail -40 /tmp/cov3-build.log; exit 1; }
+log "  .gcno files: $(find . -name '*.gcno' | wc -l)"
+
+# --- build include.tcl template with ABSOLUTE source paths (.libs relative) ---
+INC_TMPL=/tmp/cov3-include.tcl
+sed -e "s#^set src_root .*#set src_root $R#" \
+    -e "s#^set test_path .*#set test_path $R/test/tcl#" \
+    -e "s#^set je_root .*#set je_root $R/../je#" \
+    -e "s#^set tcl_utils .*#set tcl_utils $R/test/tcl_utils#" \
+    "$B/include.tcl" > "$INC_TMPL"
+
+mkrundir(){ # dir  -- isolated rundir: symlinks .libs + util wrappers + include.tcl
+  local rd="$1"; mkdir -p "$rd"
+  ln -sfn "$B/.libs" "$rd/.libs"
+  cp "$INC_TMPL" "$rd/include.tcl"
+  for f in "$B"/db_* "$B"/berkdb_svc "$B"/test_micro; do
+    bn=$(basename "$f")
+    case "$bn" in *.o|*.d|*.lo|*.gcno|*.gcda|*.c|*.h) continue;; esac
+    [ -f "$f" ] && [ -x "$f" ] && ln -sfn "$f" "$rd/$bn"
+  done
+}
+
+run_group(){ # name cap tcl-body
+  local name="$1" cap="$2" body="$3"
+  local rd="$B/rd_$name" out="/tmp/cov3-grp-$name.log"
+  mkrundir "$rd"
+  { echo "source $R/test/tcl/test.tcl"; echo "set testdir ./TESTDIR"; echo "$body"; } > "$rd/.run.tcl"
+  ( cd "$rd"; t0=$(date +%s); timeout "$cap" "$TCLBIN" .run.tcl >"$out" 2>&1; rc=$?; t1=$(date +%s)
+    fl=$(grep -c '^FAIL' "$out" 2>/dev/null || echo 0)
+    log "GRP-DONE $name rc=$rc dur=$((t1-t0))s FAILlines=$fl"
+    echo "$name rc=$rc dur=$((t1-t0)) faillines=$fl" >> "$RESULTS"
+    find "$rd/TESTDIR" -mindepth 1 -delete 2>/dev/null || true ) &
+}
+am_body(){ cat <<EOF
+foreach t \$test_names(test) {
+  if {[catch {eval run_method $1 \$t 0 1 stdout} res]} { puts "FAIL $1/\$t: \$res" }
+}
+puts "GROUP_DONE_$1"
+EOF
+}
+sub_body(){ echo "if {[catch {r $1} res]} { puts \"FAIL sub_$1: \$res\" }; puts \"GROUP_DONE_$1\""; }
+
+# =========================================================================
+# PHASE 1: parallel full Tcl suite (access methods + subsystems + rep + logverify + recd)
+# =========================================================================
+log "=== PHASE 1: launch access-method groups (parallel) ==="
+for m in btree hash recno queue heap; do run_group "am_$m" "$AM_CAP" "$(am_body $m)"; done
+
+log "=== PHASE 1: launch subsystem groups (parallel) ==="
+for sub in env archive backup fop lock log memp mutex txn sdb byte rsrc dbm ndbm hsearch sindex sec compact partition compressed; do
+  run_group "sub_$sub" "$SUB_CAP" "$(sub_body $sub)"
+done
+run_group "recd" "$SUB_CAP" "if {[catch {run_recds all 1 0} r]} { puts \"FAIL recd: \$r\" }; puts GROUP_DONE_recd"
+
+log "=== PHASE 1: launch logverify (parallel) ==="
+run_group "logverify" "$LV_CAP" \
+  "source $R/test/tcl/logverify001.tcl; source $R/test/tcl/logverify002.tcl; if {[catch {logverify001} r]} {puts \"FAIL logverify001: \$r\"}; if {[catch {logverify002} r]} {puts \"FAIL logverify002: \$r\"}; puts GROUP_DONE_logverify"
+
+# replication: SKIP known hangers rep016 rep034 repmgr024 repmgr026.
+REP_TESTS="rep001 rep002 rep003 rep005 rep006 rep007 rep008 rep009 rep010 rep011 rep012 rep013 rep014 rep015 rep019 rep020 rep021 rep022 rep023 rep024 rep025 rep026"
+REPMGR_TESTS="repmgr009 repmgr010 repmgr011 repmgr012 repmgr013 repmgr017 repmgr018 repmgr023 repmgr025 repmgr027 repmgr030 repmgr031 repmgr032 repmgr033 repmgr034"
+run_rep_one(){ # test baseport
+  local t="$1" bp="$2"
+  local rd="$B/rd_rep_$t" out="/tmp/cov3-rep-$t.log"
+  mkrundir "$rd"
+  case "$t" in rep[0-9]*) call="$t btree" ;; *) call="$t" ;; esac
+  printf 'source %s/test/tcl/test.tcl\nset testdir ./TESTDIR\nsource %s/test/tcl/reputils.tcl\nif {[catch {%s} r]} { puts "FAIL %s: $r"; exit 3 }\nputs "PASS %s"\n' \
+    "$R" "$R" "$call" "$t" "$t" > "$rd/.run.tcl"
+  ( cd "$rd"; BDBBASEPORT="$bp" timeout "$REP_CAP" "$TCLBIN" .run.tcl >"$out" 2>&1; rc=$?
+    if [ $rc -eq 124 ]; then st="HANG"; elif [ $rc -eq 0 ] && grep -q "^PASS $t" "$out"; then st="PASS"; else st="FAIL(rc=$rc)"; fi
+    log "REP-DONE $t: $st"; echo "rep_$t $st" >> "$RESULTS"
+    find "$rd/TESTDIR" -mindepth 1 -delete 2>/dev/null || true ) &
+}
+log "=== PHASE 1: launch rep0NN in-process tests (parallel) ==="
+for t in $REP_TESTS; do run_rep_one "$t" 30100; done
+log "=== PHASE 1: launch repmgrNN socket tests (parallel, distinct base ports) ==="
+i=0
+for t in $REPMGR_TESTS; do
+  bp=$((31000 + i*200)); i=$((i+1)); run_rep_one "$t" "$bp"
+  while [ "$(jobs -rp | wc -l)" -ge 48 ]; do sleep 2; done
+done
+log "=== PHASE 1: all groups launched; waiting ==="
+wait
+log "=== PHASE 1 COMPLETE. gcda=$(find .libs -name '*.gcda' | wc -l) ==="
+
+# =========================================================================
+# PHASE 2: COV_* blocks -- curated subset + all C drivers (adds to .gcda)
+# NOTE: run_coverage.sh normally wipes .gcda + rebuilds; we call the pieces
+# directly here so PHASE 1 counts survive.
+# =========================================================================
+log "=== PHASE 2: curated COV_TESTS subset (crypto/stat/mvcc/lock/compression) ==="
+COV_TESTS="lock001: txn001: ssi001: ssi002: env007: lock007: \
+  btree/test001 btree/test111 test143:btree \
+  hash/test001 hash/test006 hash/test010 hash/test025 hash/test077 \
+  queue/test001 queue/test007 queue/test025 \
+  recno/test001 recno/test006 recno/test024 recno/test025 \
+  heap/test001 heap/test013 heap/test024 \
+  run_range_partition@test001@btree run_partition_callback@test001@btree \
+  logverify001: logverify002: env020: statprint001: mvcc001: sec001: sec002:"
+subsetrd="$B/rd_covsubset"; mkrundir "$subsetrd"
+runtcl="$subsetrd/.cov-run.tcl"
+{
+  echo "source $R/test/tcl/test.tcl"
+  echo 'set testdir ./TESTDIR'
+  for pair in $COV_TESTS; do
+    case "$pair" in
+    *@*) p="${pair%%@*}"; rest="${pair#*@}"; t="${rest%%@*}"; m="${rest#*@}"
+      printf 'source %s/test/tcl/%s.tcl\n' "$R" "$t"
+      printf 'if {[catch {%s %s %s 0 1} res]} { puts "FAIL %s/%s/%s: $res" }\n' "$p" "$t" "$m" "$p" "$t" "$m"
+      printf 'puts "PASS %s/%s/%s"\n' "$p" "$t" "$m" ;;
+    */*) m="${pair%%/*}"; t="${pair#*/}"
+      printf 'source %s/test/tcl/%s.tcl\n' "$R" "$t"
+      printf 'if {[catch {run_method %s %s 0 1} res]} { puts "FAIL %s/%s: $res" }\n' "$m" "$t" "$m" "$t"
+      printf 'puts "PASS %s/%s"\n' "$m" "$t" ;;
+    *) t="${pair%%:*}"; a="${pair#*:}"
+      printf 'source %s/test/tcl/%s.tcl\n' "$R" "$t"
+      printf 'if {[catch {eval %s %s} res]} { puts "FAIL %s: $res" }\n' "$t" "$a" "$t"
+      printf 'puts "PASS %s"\n' "$t" ;;
+    esac
+  done
+} > "$runtcl"
+( cd "$subsetrd"; timeout 3000 "$TCLBIN" .cov-run.tcl >/tmp/cov3-subset.log 2>&1
+  grep -cE '^FAIL' /tmp/cov3-subset.log | xargs -I{} echo "covsubset faillines={}" >> "$RESULTS"
+  find "$subsetrd/TESTDIR" -mindepth 1 -delete 2>/dev/null || true )
+log "  subset done: $(grep -cE '^PASS' /tmp/cov3-subset.log) pass / $(grep -cE '^FAIL' /tmp/cov3-subset.log) fail"
+
+log "=== PHASE 2: C drivers (XA + upgrade + os_aio + backup + recd_compact) ==="
+run_driver(){ # name script
+  local name="$1" scr="$2"
+  if sh "$scr" >/tmp/cov3-$name.log 2>&1; then echo "PASS $name"; echo "driver_$name PASS" >> "$RESULTS"
+  else echo "FAIL $name (rc=$?)"; echo "driver_$name FAIL" >> "$RESULTS"; tail -5 /tmp/cov3-$name.log; fi
+}
+run_driver xa          "$R/test/xa/run_xa_direct.sh"
+run_driver db_upgrade  "$R/test/db/run_upgrade.sh"
+run_driver os_aio      "$R/test/os/run_os_aio.sh"
+run_driver backup      "$R/test/backup/run_backup_direct.sh"
+run_driver recd_compact "$R/test/db/run_recd_compact.sh"
+log "  .gcda after C drivers: $(find .libs -name '*.gcda' | wc -l)"
+
+# COV_DEAD_REG: deadlock detector + DB_REGISTER (driver-per-test)
+log "=== PHASE 2: deadlock + DB_REGISTER drivers ==="
+DR_CAP=300
+dead_reg=( "dead001:dead001 {2 4}" "dead002:dead002 {2 4}" "dead003:dead003 {2 4}" \
+  "dead004:dead004" "dead005:dead005 {4}" "dead006:dead006 {2 4}" "env012:env012" )
+drrd="$B/rd_deadreg"; mkrundir "$drrd"; dregtcl="$drrd/.cov-deadreg.tcl"
+for spec in "${dead_reg[@]}"; do
+  name="${spec%%:*}"; call="${spec#*:}"
+  printf 'source %s/test/tcl/test.tcl\nset testdir ./TESTDIR\nif {[catch {%s} r]} { puts "FAIL %s: $r"; exit 3 }\nputs "PASS %s"\n' \
+    "$R" "$call" "$name" "$name" > "$dregtcl"
+  ( cd "$drrd"; timeout "$DR_CAP" "$TCLBIN" .cov-deadreg.tcl >/tmp/cov3-dreg-$name.log 2>&1; rc=$?
+    pkill -f 'wrap.tcl' 2>/dev/null||true; pkill -f 'ddscript' 2>/dev/null||true
+    pkill -f 'envscript' 2>/dev/null||true; pkill -f 'db_deadlock' 2>/dev/null||true
+    if [ $rc -eq 124 ]; then echo "HANG $name"; echo "dreg_$name HANG">>"$RESULTS"
+    elif [ $rc -eq 0 ] && grep -q "^PASS $name" /tmp/cov3-dreg-$name.log; then echo "PASS $name"; echo "dreg_$name PASS">>"$RESULTS"
+    else echo "FAIL $name (rc=$rc)"; echo "dreg_$name FAIL">>"$RESULTS"; fi
+    find "$drrd/TESTDIR" -mindepth 1 -delete 2>/dev/null || true )
+done
+
+# COV_RECD extra curated recd tests (driver-per-test) -- adds redo/undo branches
+log "=== PHASE 2: recd recovery-record handler tests ==="
+RECD_CAP=300
+recd_tests=( "recd002:btree:0" "recd002:hash:0" "recd002:queue:0" "recd002:recno:0" \
+  "recd004:btree:" "recd005:btree:" "recd005:hash:" "recd005:queue:" "recd005:recno:" \
+  "recd006:btree:" "recd006:hash:" "recd008:btree:" "recd009:btree:" "recd010:btree:" \
+  "recd013:btree:" "recd013:hash:" "recd014:queueext:" "recd016:btree:" "recd017:btree:" \
+  "recd018:btree:" "recd019:btree:" "recd020:btree:" "recd022:btree:" "recd023:btree:" \
+  "recd024:btree:" "recd025:btree:" )
+recdrd="$B/rd_recdcov"; mkrundir "$recdrd"; recdtcl="$recdrd/.cov-recd.tcl"
+for spec in "${recd_tests[@]}"; do
+  t="${spec%%:*}"; rest="${spec#*:}"; m="${rest%%:*}"; a="${rest#*:}"
+  printf 'source %s/test/tcl/test.tcl\nset testdir ./TESTDIR\nsource %s/test/tcl/%s.tcl\nif {[catch {eval %s %s %s} r]} { puts "FAIL %s %s: $r"; exit 3 }\nputs "PASS %s %s"\n' \
+    "$R" "$R" "$t" "$t" "$m" "$a" "$t" "$m" "$t" "$m" > "$recdtcl"
+  ( cd "$recdrd"; timeout "$RECD_CAP" "$TCLBIN" .cov-recd.tcl >/tmp/cov3-recd-$t-$m.log 2>&1; rc=$?
+    pkill -f 'recdscript' 2>/dev/null || true
+    if [ $rc -eq 124 ]; then echo "HANG $t $m"; echo "recd_${t}_$m HANG">>"$RESULTS"
+    elif [ $rc -eq 0 ] && grep -q "^PASS $t $m" /tmp/cov3-recd-$t-$m.log; then echo "PASS $t $m"; echo "recd_${t}_$m PASS">>"$RESULTS"
+    else echo "FAIL $t $m (rc=$rc)"; echo "recd_${t}_$m FAIL">>"$RESULTS"; fi
+    find "$recdrd/TESTDIR" -mindepth 1 -delete 2>/dev/null || true )
+done
+log "=== PHASE 2 COMPLETE. gcda=$(find .libs -name '*.gcda' | wc -l) ==="
+
+# =========================================================================
+# PHASE 3: single lcov capture from .libs, merge everything
+# =========================================================================
+log "=== PHASE 3: lcov capture from .libs ==="
+lcov --capture --directory .libs --output-file coverage3.info --gcov-tool gcov \
+  --rc geninfo_unexecuted_blocks=1 --branch-coverage --ignore-errors "$IGN" >/tmp/cov3-lcov.log 2>&1 \
+  || { echo "LCOV CAPTURE FAILED"; tail -30 /tmp/cov3-lcov.log; exit 1; }
+lcov --extract coverage3.info "*/src/*" --output-file cov3-src-all.info --branch-coverage --ignore-errors "$IGN" >/dev/null 2>&1
+lcov --remove cov3-src-all.info "*/dbinc_auto/*" --output-file cov-src.info --branch-coverage --ignore-errors "$IGN" >/dev/null 2>&1
+log "=== SUMMARY ==="; lcov --summary cov-src.info --branch-coverage --ignore-errors "$IGN" 2>&1 | tee /tmp/cov3-summary.txt
+log "ranking"; python3 "$here/rank_coverage.py" cov-src.info > /tmp/cov3-ranking.txt 2>&1
+log "subsystems"; python3 "$here/subsystem_breakdown.py" cov-src.info > /tmp/cov3-subsystems.txt 2>&1
+cp cov-src.info /tmp/cov3-cov-src.info
+T_END=$(date +%s)
+echo "WALL_SECONDS=$((T_END-T_START))" | tee /tmp/cov3-wall.txt
+echo "=== TOP 30 COLD FILES ==="; head -31 /tmp/cov3-ranking.txt
+echo "=== SUBSYSTEMS ==="; cat /tmp/cov3-subsystems.txt
+echo "=== RESULTS ==="; sort "$RESULTS"
+touch "$DONE"; log "ALL DONE"