What is an in-memory Queue in Data Structures?


In this tutorial, we will learn about the in-memory queue in the data structure. A queue is a general data structure that inserts and removes elements with some pattern. It uses the First In First Out approach for its processing. An array and linked lists are used to implement a queue.

In-Memory Queue

A queue can be visualized as a continuous memory (using an array queue) for storing data types. It is stored in secondary memory. In-memory Queue is different from a simple queue only in terms of its storage area. It is stored in the RAM of your computer.

In-memory queue uses the FIFO (First In First Out) principle for inserting and removing elements. According to FIFO, the first entered element in the Queue will be removed first from it. A priority queue and a queue can be an in-memory queue.

Key Features of the In-Memory Queue

  • The in-memory queue is also called the memory queue.

  • It is stored in the RAM, making it faster than the normal queue.

  • We can not use an in-memory queue for long-term data storage. When the computer turns off, it removes the stored data. It is a volatile queue.

  • It is used for a fast execution process, where time is the main concern.

  • In-memory Queue consumes more memory.

  • Using in-memory is an expensive affair due to its use of RAM for its storage.

  • It is a temporary Queue.

In-memory queue provides faster and safer execution. It can be used for communication between applications, multithreaded programs, scheduling, processing bulk data, message passing, and real-time processing.

Due to faster execution speed, in-memory queues are used in applications to enhance their performance and scalability. It helps applications with faster response time and better versions. In-build memory is used in various forms like message queues, task queues, and print queues.

Task Queue is a queue that is bounded by some task. The defined tasks are stored in RAM and are retrieved in the order they are inserted.

Message Queue is the Queue with some messages as its elements. These messages are stored one by one and are fastly executed due to their primary storage memory.

Print Queue is the Queue for printing some data. It is stored as a Queue and waits for its execution using the FIFO principle.

Applications of the In-Memory Queue

1. Operating System

In-memory is used in operating systems to manage applications and system resources. The operating system is responsible for various application tasks like interaction with hardware, allotting memory, providing an interface to communicate with other applications, managing platforms, and many more.

Operating systems use this queue for fast execution as applications do not wait much.

Various Operating systems like Windows 7, Windows 8, Windows 9, Windows Vista, and Windows XP use an in-memory queue.

2. Software

In many software, an in-memory queue is used as a middle-man for communication between different processes. It helps in passing messages by storing them in FIFO order and executing them. For example, Java Message Service uses an in-memory queue.

3. Applications

Various applications use in-memory for sharing messages and communicating between different components and processes. The gaming application uses an in-memory queue to store the player's actions in the game.

The trading application uses it for the execution of trading transactions.

An example of a Web application that uses in-memory is Apache Active MQ.


The in-memory queue is used in those processes that need a quick response with dynamic nature of storing the data. It is expensive to manage but its faster execution helps in faster communication among software components and the working of the Operating System.