Debugging

Chapter 49: Debugging Tools & Techniques

Overview

This chapter covers tools and techniques for debugging blockchain nodes.

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49.1 pprof Profiling

Enable pprof

geth --pprof --pprof.addr 0.0.0.0 --pprof.port 6061

Access

# View profiles
curl http://localhost:6061/debug/pprof/

# CPU profile
go tool pprof http://localhost:6061/debug/pprof/profile

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49.2 Debug API

Enable Debug API

geth --http --http.api eth,net,web3,debug

Common Debug Calls

# Get block with more info
curl -X POST http://localhost:8545 \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"debug_getBlockRlp","params":["0x0"],"id":1}'

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49.3 Trace Transactions

Enable Tracing

# Start node with tracing
geth --http --http.api eth,net,web3,debug,trace

Trace Call

curl -X POST http://localhost:8545 \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc":"2.0","method":"trace_block","params":["0x0"],"id":1}'

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49.4 System Tools

# Check CPU
top
htop

# Check Memory
free -h

# Check Disk I/O
iostat -x 1

# Check Network
netstat -i

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Summary

• Use pprof for performance analysis
• Debug API for detailed block info
• Trace for transaction analysis

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Last Updated: 2026-02-20