Redis

Redis command: BF.INFO

"Bloom Filter is a probabilistic data structure in Redis that efficiently determines set membership. BF.INFO provides valuable information about its status, configuration, and usage."

NIM

— 2 min read
Redis command: BF.INFO
Redis command: BF.INFO

BF.INFO: Returns Information about a Bloom Filter

In this blog post, we will explore the BF.INFO command in Redis. BF.INFO provides valuable information about the status, configuration, and usage of a Redis Bloom Filter. Let's dive into the details!

What is a Bloom Filter?

A Bloom Filter is a probabilistic data structure that efficiently determines whether an element is a member of a set. It is particularly useful for applications where false positives are acceptable, but false negatives are not. Bloom Filters have a wide range of applications, including spell checkers, duplicate removal, malware detection, and more.

BF.INFO Command Syntax

The BF.INFO command has the following syntax:

BF.INFO filter-key

The filter-key is the unique identifier for the Bloom Filter you want to retrieve information about.

BF.INFO Command Usage

To use the BF.INFO command, you need to have a Bloom Filter set up in your Redis instance. If you are not familiar with setting up and using a Redis Bloom Filter, make sure to check out our previous blog post on Redis Bloom Filters.

Once you have a Bloom Filter created, you can use the BF.INFO command to retrieve information about it. Here's an example:

BF.INFO my-filter

This command will return a detailed summary of the Bloom Filter with the key my-filter. The information will include the current capacity, number of inserted elements, false positive probability, and more.

BF.INFO Command Response

The BF.INFO command returns a JSON object with the following fields:

  • capacity: The desired capacity of the Bloom Filter
  • size: The actual size of the Bloom Filter in bytes
  • filter-size: The number of bits used by the Bloom Filter
  • number-of-inserted-elements: The number of elements inserted into the Bloom Filter
  • number-of-filtered-elements: The number of elements filtered by the Bloom Filter
  • number-of-hash-functions: The number of hash functions used by the Bloom Filter
  • false-positive-probability: The probability of a false positive occurring in the Bloom Filter
  • num-samples: The number of samples used for estimating the false positive rate

Here's an example response:

{
  "capacity": 100000,
  "size": 84855,
  "filter-size": 841728,
  "number-of-inserted-elements": 5000,
  "number-of-filtered-elements": 2700,
  "number-of-hash-functions": 7,
  "false-positive-probability": 0.016,
  "num-samples": 1000
}

Summary

The BF.INFO command in Redis provides valuable information about the status, configuration, and usage of a Bloom Filter. By using this command, you can easily monitor the effectiveness of your Bloom Filter and adjust its capacity and other parameters as needed. Understanding the returned information can help you optimize the performance of your application and ensure accurate results.

Stay tuned for more Redis command guides, where we'll explore additional commands and their applications. Happy coding!

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