Which Data Structure Helps Concurrent Insertion?


Angela Bailey

When it comes to concurrent insertion, choosing the right data structure is crucial. The data structure we select should not only allow multiple threads to insert elements concurrently but also ensure that these insertions do not result in any data corruption or inconsistency. In this article, we will explore different data structures that facilitate concurrent insertion and discuss their pros and cons.

1. ConcurrentLinkedQueue

The ConcurrentLinkedQueue is a thread-safe implementation of the Queue interface in Java’s java.util.concurrent package.

It is specifically designed for concurrent access scenarios where multiple threads need to insert elements simultaneously.

This data structure uses a lock-free algorithm called “nonblocking linked list” to handle concurrent operations efficiently. Each element in the queue contains a reference to the next element, allowing for easy insertion at the end without any contention between threads.

2. CopyOnWriteArrayList

If you need a concurrent list that supports high read concurrency and infrequent write operations, the CopyOnWriteArrayList is an excellent choice.

It guarantees thread-safety without any explicit locking mechanisms.

The key feature of this data structure is that it creates a new copy of the underlying array whenever an element is inserted or removed. This approach ensures that ongoing reads are not affected by write operations and allows multiple threads to read from the list concurrently without any synchronization overhead.

3. ConcurrentHashMap

The ConcurrentHashMap is a highly efficient thread-safe implementation of the Map interface in Java’s java.concurrent.

It provides excellent concurrency for both read and write operations.

This data structure divides the underlying map into segments, each with its lock. This allows multiple threads to insert elements concurrently as long as they belong to different segments. It achieves a good balance between thread-safety and performance by reducing the contention on locks.

4. ConcurrentSkipListSet

The ConcurrentSkipListSet is a concurrent implementation of the SortedSet interface in Java’s java.

It provides a sorted set with logarithmic time complexity for most operations.

This data structure uses a skip list, which is a linked list with multiple layers of nodes, to facilitate concurrent insertions efficiently. Each layer contains a subset of elements from the layer below, allowing for quick navigation and insertion.


Choosing the right data structure for concurrent insertion depends on your specific requirements and the characteristics of your application. The ConcurrentLinkedQueue, CopyOnWriteArrayList, ConcurrentHashMap, and ConcurrentSkipListSet are just a few examples of data structures that can handle concurrent insertions effectively.

To make an informed decision, consider factors such as read/write ratios, expected concurrency levels, and the ordering requirements of your data. With careful consideration, you can ensure that your application handles concurrent insertions efficiently without compromising data integrity.