How to fix ERR EXEC without MULTI in Redis

RedisINTERMEDIATEMEDIUM

This error occurs when EXEC is called without first starting a transaction with MULTI. It typically happens due to connection loss or improper transaction handling in client libraries. Fix it by ensuring MULTI is called before EXEC and using connection pooling.

What this error means

The "ERR EXEC without MULTI" error means you attempted to execute the EXEC command without first calling MULTI to begin a transaction. In Redis, transactions are started with MULTI, which puts the connection into a transaction mode where subsequent commands are queued instead of executed immediately. When you call EXEC, all queued commands are executed atomically. If EXEC is called outside of this context, Redis rejects it with this error. This error is fundamentally about mismatched transaction boundaries—the server is waiting for MULTI to initiate a transaction block, but received EXEC instead.

How to fix "ERR EXEC without MULTI"

1Verify MULTI is called before EXEC

Review your code to ensure that every EXEC is preceded by a MULTI command. The basic transaction pattern should always be:

bash

MULTI
[queued commands]
EXEC

If you call EXEC without MULTI, Redis cannot process it. Use a try-finally block to ensure proper cleanup:

javascript

client.multi();
try {
  client.set("key1", "value1");
  client.set("key2", "value2");
  await client.exec();
} catch (err) {
  client.discard();
  throw err;
}

2Use SessionCallback in Spring Redis

If using Spring Data Redis, the most common cause is that different connections are used for MULTI and EXEC. Spring Data Redis uses a connection pool, and each command may use a different connection by default. Use SessionCallback to ensure all transaction commands use the same connection:

java

redisTemplate.execute(new SessionCallback() {
  public Object execute(RedisOperations operations) throws DataAccessException {
    operations.multi();
    operations.opsForValue().set("key1", "value1");
    operations.opsForValue().set("key2", "value2");
    return operations.exec();
  }
});

SessionCallback ensures that watch, multi, and exec all run on the same Redis connection, preventing the "EXEC without MULTI" error.

3Enable connection pooling and increase pool size

If errors occur during high load or concurrency, your connection pool may be exhausted. Monitor and increase the pool size in your Redis client configuration:

For Jedis (Spring Redis):

java

@Bean
public JedisPoolConfig jedisPoolConfig() {
  JedisPoolConfig config = new JedisPoolConfig();
  config.setMaxTotal(100);       // Max connections
  config.setMaxIdle(20);         // Max idle connections
  config.setMinIdle(10);         // Min idle connections
  config.setTestOnBorrow(true);
  config.setTestOnReturn(true);
  return config;
}

For Node.js Redis:

javascript

const client = redis.createClient({
  socket: {
    maxRetriesPerRequest: null,
    enableReadyCheck: false,n  },
});

4Implement retry logic with exponential backoff

For intermittent errors during transient connection issues, implement retry logic:

javascript

async function executeTransaction(client, commands) {
  let retries = 3;
  let lastError;
  
  while (retries > 0) {
    try {
      const pipeline = client.pipeline();
      pipeline.multi();
      commands.forEach(cmd => pipeline[cmd.name](...cmd.args));
      const result = await pipeline.exec();
      return result;
    } catch (err) {
      lastError = err;
      retries--;
      if (retries > 0) {
        await new Promise(resolve => setTimeout(resolve, Math.pow(2, 3 - retries) * 100));
      }
    }
  }
  throw lastError;
}

5Check for connection drops or server restarts

The "EXEC without MULTI" error can also occur if the Redis server restarts between MULTI and EXEC. Implement connection monitoring to detect and handle disconnections:

javascript

client.on("error", (err) => {
  console.error("Redis error:", err);
  // Optionally reconnect
});

client.on("reconnecting", () => {
  console.log("Attempting to reconnect to Redis...");
});

Ensure your client library is configured to automatically reconnect on connection loss. Most modern clients (ioredis, node-redis 4+) handle this by default.

How to fix ERR EXEC without MULTI in Redis

What this error means

Typical symptoms

Common causes

How to fix "ERR EXEC without MULTI"

Advanced notes

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