I am new to Redisson and tried to implement a ReadWriteLock downgrade but after doing the release of the writeLock, Redisson is not renewing the lock even when there is still a readlock and after 30 seconds the readlock is gone.

I created a simple example to test the downgrade but it is not working as expected. In the first part, the code is creating a readwritelock and then acquiring a writelock and readlock. To check that Redisson was keeping these locks without issues, every 5 seconds the code is checking the TTL and the locks counts and everything looks fine.

However after releasing the writeLock, Redisson is not longer renewing the lock and after 30 seconds is gone. I was expecting Redisson to continue keeping the readLock alive until it is released.

import java.util.concurrent.TimeUnit;

import org.redisson.Redisson;
import org.redisson.api.RReadWriteLock;
import org.redisson.api.RedissonClient;
import org.redisson.config.Config;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ReadWriteLockExample {

    private static final Logger logger = LoggerFactory.getLogger(ReadWriteLockExample.class);

    public static void main(String[] args) {

        Config config = new Config();
        config.useSingleServer().setAddress("redis://127.0.0.1:6379");

        RedissonClient redisson = Redisson.create(config);

        RReadWriteLock rwlock = redisson.getReadWriteLock("myLock");

        rwlock.writeLock().lock();
        logger.info("Write lock acquired");
        logger.info("Write lock count: " + rwlock.writeLock().getHoldCount());
        logger.info("Read lock count: " + rwlock.readLock().getHoldCount());

        rwlock.readLock().lock();
        logger.info("Read lock acquired");
        logger.info("Write lock count: " + rwlock.writeLock().getHoldCount());
        logger.info("Read lock count: " + rwlock.readLock().getHoldCount());
        
        for (int i = 0; i < 6; i++) {
            logger.info("Lock TTL: {} Write lock count {} Read lock count: {}", rwlock.readLock().remainTimeToLive(),
                    rwlock.writeLock().getHoldCount(), rwlock.readLock().getHoldCount());
            try {
                TimeUnit.SECONDS.sleep(5);
            } catch (InterruptedException ie) {
                Thread.currentThread().interrupt();
            }
        }

        // Lock downgrading
        rwlock.writeLock().unlock();
        logger.info("Write lock released/downgraded");
        logger.info("Write lock count: " + rwlock.writeLock().getHoldCount());
        logger.info("Read lock count: " + rwlock.readLock().getHoldCount());

        // After 30 seconds, I would expect to see the readLock still locking
        // However is gone
        for (int i = 0; i < 6; i++) {
            logger.info("Lock TTL: {} Write lock count {} Read lock count: {}", rwlock.readLock().remainTimeToLive(),
                    rwlock.writeLock().getHoldCount(), rwlock.readLock().getHoldCount());
            try {
                TimeUnit.SECONDS.sleep(5);
            } catch (InterruptedException ie) {
                Thread.currentThread().interrupt();
            }
        }

        logger.info("Write lock count after 30s: " + rwlock.writeLock().getHoldCount());
        logger.info("Read lock count after 30s: " + rwlock.readLock().getHoldCount());

        // Releasing ReadLock
        rwlock.readLock().unlock();
        logger.info("Read lock released");
        logger.info("Write lock count: " + rwlock.writeLock().getHoldCount());
        logger.info("Read lock count: " + rwlock.readLock().getHoldCount());

        redisson.shutdown();

    }

}

The output:

11:34:43.417 [main] INFO  org.redisson.Version - Redisson 3.16.8
11:34:44.382 [redisson-netty-2-14] INFO  org.redisson.connection.pool.MasterPubSubConnectionPool - 1 connections initialized for 127.0.0.1/127.0.0.1:6379
11:34:44.405 [redisson-netty-2-19] INFO  org.redisson.connection.pool.MasterConnectionPool - 24 connections initialized for 127.0.0.1/127.0.0.1:6379
11:34:44.455 [main] INFO  com.test.redis.ReadWriteLockExample - Write lock acquired
11:34:44.459 [main] INFO  com.test.redis.ReadWriteLockExample - Write lock count: 1
11:34:44.461 [main] INFO  com.test.redis.ReadWriteLockExample - Read lock count: 0
11:34:44.463 [main] INFO  com.test.redis.ReadWriteLockExample - Read lock acquired
11:34:44.465 [main] INFO  com.test.redis.ReadWriteLockExample - Write lock count: 1
11:34:44.466 [main] INFO  com.test.redis.ReadWriteLockExample - Read lock count: 1
11:34:44.469 [main] INFO  com.test.redis.ReadWriteLockExample - Lock TTL: 29997 Write lock count 1 Read lock count: 1
11:34:49.484 [main] INFO  com.test.redis.ReadWriteLockExample - Lock TTL: 24988 Write lock count 1 Read lock count: 1
11:34:54.514 [main] INFO  com.test.redis.ReadWriteLockExample - Lock TTL: 19961 Write lock count 1 Read lock count: 1
11:34:59.541 [main] INFO  com.test.redis.ReadWriteLockExample - Lock TTL: 25019 Write lock count 1 Read lock count: 1
11:35:04.569 [main] INFO  com.test.redis.ReadWriteLockExample - Lock TTL: 19996 Write lock count 1 Read lock count: 1
11:35:09.582 [main] INFO  com.test.redis.ReadWriteLockExample - Lock TTL: 25074 Write lock count 1 Read lock count: 1
11:35:14.596 [main] INFO  com.test.redis.ReadWriteLockExample - Write lock released/downgraded
11:35:14.599 [main] INFO  com.test.redis.ReadWriteLockExample - Write lock count: 0
11:35:14.603 [main] INFO  com.test.redis.ReadWriteLockExample - Read lock count: 1
11:35:14.615 [main] INFO  com.test.redis.ReadWriteLockExample - Lock TTL: 20042 Write lock count 0 Read lock count: 1
11:35:19.635 [main] INFO  com.test.redis.ReadWriteLockExample - Lock TTL: 15021 Write lock count 0 Read lock count: 1
11:35:24.647 [main] INFO  com.test.redis.ReadWriteLockExample - Lock TTL: 10009 Write lock count 0 Read lock count: 1
11:35:29.658 [main] INFO  com.test.redis.ReadWriteLockExample - Lock TTL: 4998 Write lock count 0 Read lock count: 1
11:35:34.681 [main] INFO  com.test.redis.ReadWriteLockExample - Lock TTL: -2 Write lock count 0 Read lock count: 0
11:35:39.709 [main] INFO  com.test.redis.ReadWriteLockExample - Lock TTL: -2 Write lock count 0 Read lock count: 0
11:35:44.727 [main] INFO  com.test.redis.ReadWriteLockExample - Write lock count after 30s: 0
11:35:44.731 [main] INFO  com.test.redis.ReadWriteLockExample - Read lock count after 30s: 0
11:35:44.738 [main] INFO  com.test.redis.ReadWriteLockExample - Read lock released
11:35:44.742 [main] INFO  com.test.redis.ReadWriteLockExample - Write lock count: 0
11:35:44.745 [main] INFO  com.test.redis.ReadWriteLockExample - Read lock count: 0

I run this example on Redis server 6.2.5 on Ubuntu 20.04.3 LTS using WSL (Windows 10). Not sure if this a bug or I am missing something.