Does Go's Garbage Collector Reclaim Underlying Array Memory When Slices Are Deleted?

Does Go Garbage Collect Parts of Slices?

In the context of Go programming, slices are a data structure that operates as a variable-length, dynamically allocated array. This raises questions about how the garbage collector (GC) handles slices as parts of arrays may not be actively referenced.

Understanding Slices and Garbage Collection

Slices are descriptors that provide a runtime-efficient way to reference and modify portions of arrays. When you create a slice, it shares the underlying storage with the corresponding array. This means that the array itself is not duplicated, but rather the slice provides a view into a portion of the array.

If all slices referencing a particular array are deleted or no longer contain live references to that array, the GC is able to free the array's memory. However, slices are not created by copying the entire array but rather by reslicing the existing array, creating multiple slices that share the same underlying storage.

Garbage Collection of Sliced Arrays

In the example code provided, the underlying array for the slice q will not be freed even after elements are removed using PopFront. This is because the slice q is still referencing the underlying array, preventing the GC from releasing it.

Official Clarification

The official Go documentation and blog posts confirm this behavior:

• The Go Language Specification states that "A slice, once initialized, is always associated with an underlying array."
• A blog post by Andrew Gerrand highlights that "The full array will be kept in memory until it is no longer referenced."

Implications for Shared Arrays and Garbage Collection

While the underlying array of a sliced array may not be garbage collected, it's important to note that:

• If new elements are added to the queue (slice), a new array may be allocated and copied. This could result in the old array being garbage collected if no other references exist.
• Zeroing out removed elements is recommended to prevent memory leaks, especially if the slice contains pointers to other data structures.

The above is the detailed content of Does Go's Garbage Collector Reclaim Underlying Array Memory When Slices Are Deleted?. For more information, please follow other related articles on the PHP Chinese website!