Why Are Electrs Address Balance Queries Slow (~900ms) on My Dockerized Bitcoin Full Node?

[PanagiotisDrakatos]

I’m running a Bitcoin Core full node (bitcoind) and using romanz/electrs (via Docker) to provide btc explorer server functionality for querying address balances and related wallet info. However, I’m experiencing unexpectedly high latency: querying the balance for a random address consistently takes around 600-900 ms via btc-rpc-explorer RPC interface. For addresses with an enormous number of transactions, the query can take some seconds instead of ms

This is the Docker Compose yml file:

services:
  bitcoin_service:
    build:
      context: .
      dockerfile: Bitcoin.Dockerfile
      args:
        BITCOIN_VERSION: ${BTC_VERSION}
    image: bitcoin_full_node
    ports:
      - 8333:8333
      - 8332:8332
    volumes:
      - bitcoin_volume:/home/btc-user/.bitcoin
    networks:
      network:
        ipv4_address: 192.168.1.219
    healthcheck:
      test: [
        "CMD",
        "bitcoin-cli",
        "-rpccookiefile=/home/btc-user/.bitcoin/btc.cookie",
        "-rpcport=8332",
        "-rpcconnect=192.168.1.219",
        "getblockchaininfo"
      ]
      interval: 40s
      timeout: 60s
      retries: 45

  electrs:
    image: electrs:latest
    build:
      context: ./electrs/.
    container_name: electrs
    restart: always
    ports:
      - "50001:50001"    # Electrum TCP port exposed on host and container
    environment:
      - ELECTRS_NETWORK=bitcoin
      - ELECTRS_DAEMON_RPC_ADDR=192.168.1.219:8332
      - ELECTRS_DAEMON_P2P_ADDR=192.168.1.219:8333
      - ELECTRS_ELECTRUM_RPC_ADDR=192.168.1.223:50001
      - ELECTRS_LOG_FILTERS=INFO
      - ELECTRS_DB_DIR=/home/electrs/db
      - ELECTRS_VERBOSE_RPC_LOGS=true
      - ELECTRS_IGNORE_MEMPOOL=true
      - ELECTRS_TIMESTAMP_CACHE_CAPACITY=1000000  # Higher cache for faster lookups
      - ELECTRS_INDEX_LOOKUP_LIMIT=10000
      - ELECTRS_COOKIE_FILE=/home/btc-user/.bitcoin/btc.cookie
      - ELECTRS_THREADS=4
      - ELECTRS_DB_CACHE_SIZE=4096
    volumes:
      - electrs_db:/home/electrs/db
      - bitcoin_volume:/home/btc-user/.bitcoin:ro    # Mount same bitcoin data volume (read-only)
    networks:
      network:
        ipv4_address: 192.168.1.223 # new IP in the same subnet
    healthcheck:
      test: ["CMD-SHELL", "timeout 5 bash -c 'echo > /dev/tcp/192.168.1.223/50001'"]
      interval: 40s
      timeout: 60s
      retries: 45
    depends_on:
      bitcoin_service:
        condition: service_healthy

  explorer:
    container_name: btc-rpc-explorer
    environment:
      BTCEXP_HOST: $BTCEXP_HOST
      BTCEXP_PORT: $BTCEXP_PORT
      BTCEXP_ADDRESS_API: $BTCEXP_ADDRESS_API
      BTCEXP_ELECTRUM_SERVERS: $BTCEXP_ELECTRUM_SERVERS
      BTCEXP_ELECTRUM_TXINDEX: $BTCEXP_ELECTRUM_TXINDEX
      BTCEXP_BITCOIND_URI: $BTCEXP_BITCOIND_URI
      BTCEXP_BITCOIND_USER: $BTCEXP_BITCOIND_USER
      BTCEXP_BITCOIND_PASS: $BTCEXP_BITCOIND_PASS
      BTCEXP_BITCOIND_RPC_TIMEOUT: $BTCEXP_BITCOIND_RPC_TIMEOUT
      BTCEXP_SECURE_SITE: $BTCEXP_SECURE_SITE
      BTCEXP_COIN: $BTCEXP_COIN
      BTCEXP_RPC_CONCURRENCY: $BTCEXP_RPC_CONCURRENCY
      BTCEXP_SLOW_DEVICE_MODE: $BTCEXP_SLOW_DEVICE_MODE
      BTCEXP_NO_RATES: $BTCEXP_NO_RATES
      BTCEXP_RPC_ALLOWALL: $BTCEXP_RPC_ALLOWALL
      BTCEXP_UI_TIMEZONE: $BTCEXP_UI_TIMEZONE
      BTCEXP_UI_THEME: $BTCEXP_UI_THEME
    build:
      context: ./btc-rpc-explorer/.
    image: btc-rpc-explorer:latest
    volumes:
      - bitcoin_volume:/home/btc-user/.bitcoin:ro    # Mount same bitcoin data volume (read-only)
    networks:
      network:
        ipv4_address: 192.168.1.222
    ports:
      - "3002:3002"
    depends_on:
      electrs:
        condition: service_healthy

My Setup:

Bitcoin Core runs as a full node with default (non-pruned) settings.
Electrs runs in Docker with the following environment:
ELECTRS_NETWORK=bitcoin
ELECTRS_DAEMON_RPC_ADDR=192.168.1.219:8332
ELECTRS_DAEMON_P2P_ADDR=192.168.1.219:8333
ELECTRS_ELECTRUM_RPC_ADDR=192.168.1.223:50001
ELECTRS_DB_DIR=/home/electrs/db
ELECTRS_TIMESTAMP_CACHE_CAPACITY=1000000
ELECTRS_INDEX_LOOKUP_LIMIT=10000
ELECTRS_THREADS=4
ELECTRS_DB_CACHE_SIZE=4096
Volumes: bitcoin data (read-only) and electrs DB (persistent)
Docker container has 4 threads and 4GB cache configured

Electrs and bitcoind are on the same local network.
Problem:
Despite this setup, querying a single, random address balance via Electrs takes about 900ms. This seems slow compared to other Electrum servers and my expectations for local, SSD-backed infrastructure.

Hardware Specs:

• CPU: AMD Ryzen 5 5600 3.5 GHz 6-Core Processor
• RAM: 16 GB (2 x 8GB) DDR4-3200
• Storage: Western Digital Blue SN580 2TB NVMe M.2 SSD (PCIe 4.0 x4)
• Motherboard: Gigabyte A520M K V2 Micro ATX AM4
• Network: 1GPS Download speed

Questions:

• Is this latency typical for Electrs on a Dockerized full node?
• Are there further optimizations I can make in my Docker or Electrs
  configuration to reduce balance query times?
• Is there any known bottleneck, either in RocksDB, disk I/O, or Docker networking, that
  might cause this?
• What are the typical response times others see for
  similar setups?

Any insights or tuning suggestions from the community
would be greatly appreciated!

Thank you!