What is a thread pool and in what cases is its use advisable?

A thread pool is a set of pre-created threads that are reused to perform tasks. Instead of creating a new thread for each task, a free thread from the pool is taken.

Advantages:

• Reduces overhead of creating and destroying threads.
• Controls the maximum number of threads running simultaneously.

It is advisable to use a thread pool when:

• You need to perform many short tasks in parallel.
• You want to limit the number of threads running at the same time.

Example in Python with ThreadPoolExecutor:

from concurrent.futures import ThreadPoolExecutor
import time

def task(n):
    time.sleep(1)
    return n * 2

with ThreadPoolExecutor(max_workers=3) as executor:
    results = executor.map(task, range(5))
    for r in results:
        print(r)

Here, a pool of 3 threads is created, which perform 5 tasks.