[BUG]Maximum number of transactions reached

[5d2]

V5.08

Exception Maximum number of transactions reached

CODE

var col = _db.GetCollection<T>(typeof(T).Name); result = col.Find(bse).ToList();
var col = _db.GetCollection<T>(typeof(T).Name); t = col.FindById(new ObjectId(Id)) :

[lbnascimento]

@5d2 I could not reproduce the issue. What .NET implementation are you using? Could you provide a complete sample code that I could use to reproduce the issue?

[mookid8000]

In case this could help, I can report having experienced the following (with LiteDB 5.0.9): Following some fairly heavy load, the following error error occurred:

System.ArgumentException: An entry with the same key already exists.
   at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
   at System.Collections.Generic.SortedList`2.Add(TKey key, TValue value)
   at LiteDB.Engine.BasePage.Defrag()
   at LiteDB.Engine.BasePage.InternalInsert(UInt16 bytesLength, Byte& index)
   at LiteDB.Engine.BasePage.Update(Byte index, UInt16 bytesLength)
   at LiteDB.Engine.DataPage.UpdateBlock(DataBlock currentBlock, Int32 bytesLength)
   at LiteDB.Engine.DataService.<>c__DisplayClass4_0.<<Update>g__source|0>d.MoveNext()
   at LiteDB.Engine.BufferWriter..ctor(IEnumerable`1 source)
   at LiteDB.Engine.DataService.Update(CollectionPage col, PageAddress blockAddress, BsonDocument doc)
   at LiteDB.Engine.LiteEngine.UpdateDocument(Snapshot snapshot, CollectionPage col, BsonDocument doc, IndexService indexer, DataService data)
   at LiteDB.Engine.LiteEngine.<>c__DisplayClass26_0.<Update>b__0(TransactionService transaction)
   at LiteDB.Engine.LiteEngine.AutoTransaction[T](Func`2 fn)
   at FleetManager.Model.Tech.LiteDb.LiteDbProjection`1.<Flush>d__16.MoveNext() in C:\projects-rebusfm\fm7-server\FleetManager.Model.Tech\LiteDb\LiteDbProjection.cs:line 159

when calling ILiteCollection<T>.Update(IEnumerable<T> entities).

After having thrown that error for a while, LiteDB started giving off error messages like

LiteDB.LiteException: Invalid Data on 0. Full zero: True. Page Type: Empty. Prev/Next: 0/0. UniqueID: 1959. ShareCounter: -1. 

System.InvalidCastException: Unable to cast object of type 'LiteDB.Engine.HeaderPage' to type 'LiteDB.Engine.DataPage'.

LiteDB.LiteException: Invalid Data on 0. Full zero: True. Page Type: Empty. Prev/Next: 0/0. UniqueID: 5674. ShareCounter: -1. 

LiteDB.LiteException: Invalid Collection on 1365001555. Full zero: False. Page Type: 65. Prev/Next: 1768835387/1818323316. UniqueID: 7045. ShareCounter: 9. 

System.ArgumentException: Offset and length were out of bounds for the array or count is greater than the number of elements from index to the end of the source collection.

until finally settling on

LiteDB.LiteException: Maximum number of transactions reached
   at LiteDB.Engine.TransactionMonitor.GetTransaction(Boolean create, Boolean queryOnly, Boolean& isNew)
   at LiteDB.Engine.QueryExecutor.ExecuteQuery(Boolean executionPlan)
   at LiteDB.Engine.LiteEngine.Query(String collection, Query query)
   at LiteDB.LiteQueryable`1.<ToDocuments>d__26.MoveNext()
   at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at FleetManager.Model.Tech.LiteDb.LiteDbProjection`1.<WarmUp>d__14.MoveNext() in C:\projects-rebusfm\fm7-server\FleetManager.Model.Tech\LiteDb\LiteDbProjection.cs:line 93

until the process was stopped.

[KC7465128305]

I have the same problem and I am using v5.0.9 so the bug hasn't been fixed. This is what triggers this exception:

((LiteCollection)MyDB.NoSqlDB.GetCollection("Frm")).FindOne(p => p.Id == ID);

Where POCOFrm is a very simple POCO class with four properties, two are of type string and two are of type int.

[KC7465128305]

Got another "Maximum number of transactions reached" bug when my program run the following statement:

LiteDB.IBsonDataReader reader = MyDB.NoSqlDB.Execute($"SELECT _id FROM Ctl ORDER BY _id DESC LIMIT 1");

[frankneumann]

I encountered the same exception, which was caused by the heavy use of threads within Parallel.ForEach. Unfortunately, the TransactionService for a closed thread will not be removed from the _transactions dictionary within the TransactionMonitor.
Here a finalizer for the TransactionService has to be added, which takes care of removing the transaction from the _transactions dictionary. I will provide a fix for this.

[mbdavid]

Hi @frankneumann , thanks for solving this. Can you submit a Pull Request about this bugfix?

[frankneumann]

It is here:
#1906

[balverio]

@mbdavid @frankneumann My company needs this fix, do you know when it will be released and what version?

[lbnascimento]

It is fixed in the latest release.