Getting SIGSEGV while reading data from Litedb collection simultaneously in multiple threads

Question

I am using Litedb v4 in Xamarin, I am creating liteDatabase connection and getting collections inside it once, and passing the collection to multiple threads which perform givenCollection.findALL().ToList() simultaneously. The app crashes sometimes(not always) resulting in SIGSEGV error, I am not getting what is causing this error.

Code to Reproduce

protected async virtual Task<IEnumerable<T>> ReadAllItems<T>(LiteCollection<T> collection)
{
    return await Task.Run(() =>
    {
          return collection.FindAll().ToList();
     });
}

I am getting the collection object once and passing to the above method. calling above method multiple times one after another causing the error.

This is the log I am getting:

  at <unknown> <0xffffffff>
  at System.String:FastAllocateString <0x00037>
  at System.String:CreateStringFromEncoding <0x000fb>
  at System.Text.UTF8Encoding:GetString <0x002a3>
  at LiteDB.BsonReader:ReadString <0x00143>
  at LiteDB.BsonReader:ReadElement <0x00227>
  at LiteDB.BsonReader:ReadDocument <0x0015b>
  at LiteDB.BsonReader:ReadElement <0x002af>
  at LiteDB.BsonReader:ReadDocument <0x0015b>
  at LiteDB.BsonReader:ReadElement <0x002af>
  at LiteDB.BsonReader:ReadArray <0x0015b>
  at LiteDB.BsonReader:ReadElement <0x0031f>
  at LiteDB.BsonReader:ReadDocument <0x0015b>
  at LiteDB.BsonReader:ReadElement <0x002af>
  at LiteDB.BsonReader:ReadDocument <0x0015b>
  at LiteDB.BsonReader:Deserialize <0x0009b>
  at LiteDB.QueryCursor:Fetch <0x003eb>
  at <Find>d__9:MoveNext <0x007a3>
  at <Find>d__13:MoveNext <0x00e63>
  at <Find>d__17:MoveNext <0x00593>
  at System.Collections.Generic.List`1:AddEnumerable <0x00287>
  at System.Collections.Generic.List`1:.ctor <0x0038f>
  at <>c__DisplayClass7_0`1:<ReadAllItems>b__0 <0x0013b>
  at System.Threading.Tasks.Task`1:InnerInvoke <0x000d7>
  at System.Threading.Tasks04-11 02:13:11.211 F/libc    
 (13977): Fatal signal 11 (SIGSEGV), code 1, fault addr 0x1b in tid 14021 (Thread Pool Wor)

SIGSEGV usually means some kind of memory issue occured. Can you share some more of the code you are executing? — Cheesebaron, Apr 13 '20 at 12:11
yes, https://github.com/mbdavid/LiteDB/wiki/Concurrency. And this issue doesn't occur always. — sanjiv saini, Apr 14 '20 at 07:12
If you read that document it is for `LiteRepository`, `LiteDatabase` and `LiteEngine`. Not for `LiteCollection` which you are sharing — Cheesebaron, Apr 14 '20 at 07:27
ok, that could be the reason, I will test with a single instance. As it was failing rarely on this scenario I thought we could use it. Thanks. — sanjiv saini, Apr 14 '20 at 08:51

Getting SIGSEGV while reading data from Litedb collection simultaneously in multiple threads

0 Answers0