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discord9 5287b87925 docs: memory profile scripts (#5922)
* docs: memory profile scripts

* chore: typo

* chore: comment

* Apply suggestions from code review

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* chore: newline eof

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
2025-04-18 09:28:05 +00:00

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#!/bin/bash
# Monitors greptime process memory usage every 10 minutes
# Triggers memory profile capture via `curl -X POST localhost:4000/debug/prof/mem > greptime-{timestamp}.gprof`
# when memory increases by more than 20MB since last check
# Generated profiles can be analyzed using flame graphs as described in `how-to-profile-memory.md`
# (jeprof is compiled with the database - see documentation)
# Alternative: Share binaries + profiles for analysis (Docker images preferred)
# Threshold in Kilobytes (20 MB)
threshold_kb=$((20 * 1024))
sleep_interval=$((10 * 60))
# Variable to store the last measured memory usage in KB
last_mem_kb=0
echo "Starting memory monitoring for 'greptime' process..."
while true; do
# Check if PID is provided as an argument
if [ -z "$1" ]; then
echo "$(date): PID must be provided as a command-line argument."
exit 1
fi
pid="$1"
# Validate that the PID is a number
if ! [[ "$pid" =~ ^[0-9]+$ ]]; then
echo "$(date): Invalid PID: '$pid'. PID must be a number."
exit 1
fi
# Get the current Resident Set Size (RSS) in Kilobytes
current_mem_kb=$(ps -o rss= -p "$pid")
# Check if ps command was successful and returned a number
if ! [[ "$current_mem_kb" =~ ^[0-9]+$ ]]; then
echo "$(date): Failed to get memory usage for PID $pid. Skipping check."
# Keep last_mem_kb to avoid false positives if the process briefly becomes unreadable.
continue
fi
echo "$(date): Current memory usage for PID $pid: ${current_mem_kb} KB"
# Compare with the last measurement
# if it's the first run, also do a baseline dump just to make sure we can dump
diff_kb=$((current_mem_kb - last_mem_kb))
echo "$(date): Memory usage change since last check: ${diff_kb} KB"
if [ "$diff_kb" -gt "$threshold_kb" ]; then
echo "$(date): Memory increase (${diff_kb} KB) exceeded threshold (${threshold_kb} KB). Dumping profile..."
timestamp=$(date +%Y%m%d%H%M%S)
profile_file="greptime-${timestamp}.gprof"
# Execute curl and capture output to file
if curl -sf -X POST localhost:4000/debug/prof/mem > "$profile_file"; then
echo "$(date): Memory profile saved to $profile_file"
else
echo "$(date): Failed to dump memory profile (curl exit code: $?)."
# Remove the potentially empty/failed profile file
rm -f "$profile_file"
fi
else
echo "$(date): Memory increase (${diff_kb} KB) is within the threshold (${threshold_kb} KB)."
fi
# Update the last memory usage
last_mem_kb=$current_mem_kb
# Wait for 5 minutes
echo "$(date): Sleeping for $sleep_interval seconds..."
sleep $sleep_interval
done
echo "Memory monitoring script stopped." # This line might not be reached in normal operation