[BUG] Transactions are not removed in LiteDB 5.0.18

[martijnboland]

Version
5.0.18

Describe the bug
We use a single IDatabase instance registered as singleton. Our application performs reads and writes from many different threads. After a little while, LiteDB starts throwing exceptions that the max number of transactions is reached. While inspecting TransactionMonitor, we only see an increasing number of transactions.

With 5.0.17 everything works fine and transactions are released properly.

Code to Reproduce

for (var i = 0; i < 110; i++)
{
    await Task.Run(() =>
    {
        try
        {
            var result = _collection.FindById(key);
        }
        catch (Exception ex)
        {
            // Do something with exception. After 100 iterations, the max number of transactions will be reached
        }
    });
}

Expected behavior
The code above should run without exception.

[icegothic]

Hi, I also have a "Maximum number of transactions is reached." issue on my project with versions 5.0.18 & 5.0.19! Do I need to adapt my code in some way?

Note: version 5.0.17 works fine for me too.

[hizume]

This problem occurs even in the case of a single thread.
It is reproduced in the following code:

static void Main()
{
    // Create a new database.
    using var database = new LiteDatabase("test.db");

    var collection = database.GetCollection("test");
    collection.Insert(new BsonDocument { ["_id"] = 1 });

    for (int i = 0; i < 101; i++)
    {
        try
        {
            collection.FindById(1);
        }
        catch (LiteException ex)
        {
            // An exception is thrown when i reaches 100.
            Console.WriteLine(ex.Message);
        }
    }
}

I will send a pull request to fix it.

[dgodwin1175]

@mbdavid Assuming this fix has been tested and verified, can we get a new release that includes it?

Note that we rolled this fix into 5.0.19 and found that it resolves the "Maximum number of transactions reached" error, and also the DiskWriterQueue locking issue #2307 which has been preventing us from upgrading to v5.

[alexanderdibenedetto]

Hi - what's the update on this? I see a PR linked as open. It would be good to get this issue fixed so we can update.

[kjetilgloppen]

I saw the same issue when upgrading from 5.0.12 to 5.0.19. Version 5.0.17 is the only workable solution for now it seems...

[FelixLorenz]

Hi together, are there any updates on this? Also still staying with 5.0.17 due to this issue

[PatrickSlamp]

I have an update on this issue. Not sure if this is the right spot to put it, but I noticed something with transactions not being removed. As shown in the image below when using FirstOrDefault the transaction is not removed, when using ToList() in my case fixed it. Maybe some with more elaborate knowledge of the library can confirm my suspicion. (Edit: also maybe to mention there is only one entry in the database not sure if that also matters).

[JKamsker]

This issue has been addressed and fixed in the latest commit.
A new release is coming shortly.
Reopen this issue or open a new one if this issue persists in the upcoming version please.