streaming-huge-json: 1 GiB streaming vs tree vs binding benchmark (Jackson 3.2.4, JDK 25) for the rewritten streaming post

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01CifR2BE7PBvRy5hT8TS9oz

streaming-huge-json/scripts/bench.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+# Runs each approach against the huge file under a ladder of -Xmx limits, one fresh JVM per run.
+# Streaming modes run every rung (to show memory stays flat). Tree/bind climb until the first
+# rung that succeeds, then stop. Output: output/bench.txt   (timings vary run to run)
+set -u
+cd "$(dirname "$0")/.."
+FILE="${1:-target/huge.json}"
+CP="target/classes:$(cat target/cp.txt)"
+OUT=output/bench.txt
+mkdir -p output
+{
+  echo "file: $FILE ($(stat -c %s "$FILE") bytes)"
+  echo "java: $(java -version 2>&1 | grep -v 'Picked up' | head -1)"
+  echo "cpus: $(nproc)   ram: $(free -m | awk '/Mem:/{print $2}') MB"
+  echo
+  for mode in stream hybrid; do
+    for x in 32 64 128 1024; do
+      java -Xmx${x}m -cp "$CP" com.ankurm.jackson3.streaminghuge.Scan $mode "$FILE" 2>&1 | grep -v '^Picked up'
+    done
+  done
+  for mode in tree bind; do
+    for x in 64 256 1024 2048 3072 4096 6144; do
+      line=$(timeout 900 java -Xmx${x}m -cp "$CP" com.ankurm.jackson3.streaminghuge.Scan $mode "$FILE" 2>&1 | grep -v '^Picked up'; echo "exit=${PIPESTATUS[0]}")
+      # no output at all = the JVM was SIGKILLed (exit 137) by the container's OOM killer
+      case "$line" in exit=*) line=$(printf '%-7s -Xmx=%5d MB  KILLED  no Java output, %s (SIGKILL by the OS: the heap limit was larger than free RAM)' "$mode" "$x" "$line");; *) line="${line%exit=*}"; line="${line%$'\n'}";; esac
+      echo "$line"
+      case "$line" in *" OK "*) break;; esac
+    done
+  done
+} | tee "$OUT"