RedisCommandExecutionException: ERR offset is out of range

1. Introduction

In this article, we will discuss the RedisCommandExecutionException with the specific error message "ERR offset is out of range". We will explain what this exception means and how it can be resolved by addressing the offset range issue. We will also provide a code example to demonstrate the scenario.

2. Understanding RedisCommandExecutionException

The RedisCommandExecutionException is an exception class in the Redis Java client that is thrown when a Redis command execution fails. It indicates an error in executing a Redis command, such as an invalid argument, unsupported operation, or a server-side error.

The error message "ERR offset is out of range" suggests that the offset value provided in the command is beyond the permissible range. The "offset" refers to the position index used in certain Redis commands, such as GETRANGE or SETRANGE, to specify the starting point for an operation.

3. Resolving the Offset Range Issue

When encountering the "ERR offset is out of range" error, it is necessary to review the command where the issue occurs and ensure that the offset value is within the valid range.

For example, let's consider the GETRANGE command in Redis, which retrieves a substring from a string value based on the specified start and end offsets. The general syntax for the GETRANGE command is as follows:

GETRANGE key start end

The start and end parameters represent the inclusive start and end offsets respectively. The offset value should be within the bounds of the string value.

To prevent the "ERR offset is out of range" error, ensure the following:

  1. Verify that the key exists in Redis and is associated with a string value.
  2. Check that the start and end offsets are valid positions within the string value.
  3. Make sure the start offset is less than or equal to the end offset.

Here is an example code snippet that demonstrates the correct usage of GETRANGE command in Java:

Jedis jedis = new Jedis("localhost", 6379);
String key = "mykey";
String value = "Hello, World!";

// Set the value for the key
jedis.set(key, value);

// Get a substring using GETRANGE command
String substring = jedis.getrange(key, 0, 4);

System.out.println("Substring: " + substring);

In the above example, we set a string value "Hello, World!" for the key "mykey" and then retrieve a substring using the GETRANGE command with valid start and end offsets.

4. Conclusion

The "RedisCommandExecutionException: ERR offset is out of range" indicates that the offset value used in a Redis command is beyond the valid range. This error can be resolved by ensuring that the offset is within the bounds of the relevant Redis data structure and the specific command being used.

By validating the key existence, checking the offset ranges, and ensuring the correct syntax of the command, developers can prevent this exception and ensure the smooth execution of Redis commands.

Remember to always review the Redis documentation for the specific command to understand the valid ranges and usage guidelines.

[block:classDiagram] class RedisCommandExecutionException{ +RedisCommandExecutionException(message: String) }

Reference

  • Redis Java Client Documentation: [
  • Redis Command Documentation: [