Multiple database update lags the UI android kotlin room coroutines

Question

In my android chat application, i have a Table Entity called 'Messages'. In that table the body is a Json format object which holds some data. For example the json has the form of a FileHeader, which holds some information about a file inside the chat.

data class FileHeader(
    @Expose
    @SerializedName("k")
    val fileName: String,
    @Expose
    @SerializedName("e")
    val fileDate: String,
    @Expose
    @SerializedName("z")
    val fileSize: Int,
    @Expose
    @SerializedName("h")
    val fileHash: String,
    @Expose
    @SerializedName("t")
    val totalSegments: Int,
    @Expose
    @SerializedName("s")
    var lastDownloadedSegment: Int

}

As you can see, there is a field called lastDownloadedSegment, which means, up to now how many segments have been uploaded/downloaded. So each time i download/upload a new file part i have a method that informs the fileHeader.

suspend fun updateFileHeaderMessage(serverId: Long, messageId: String, completeSegments: Int, status: Int) {
        getFileHeader(serverId, messageId)?.let {
            val newHeader = it.copy(lastDownloadedSegment = completeSegments, status = status, description = "")
            
                messageRepository.updateBodyAndFileStatus(
                    serverId, messageId,
                    EncryptString(Gson().toJson(newHeader)), status
                )
           
        }
    }

This function is called from a coroutine every time a new filepart get uploaded/downloaded (which is an information from a socket calledback).

class SocketResponseHandler {
   private val scope = CoroutineScope(Dispatchers.Main + SupervisorJob())

   fun webSocketResolver(message: String) {
      scope.launch(Dispatchers.IO) {
         // the suspend function that finally calls the updateFileHeaderMessage
         fileHandler.filePartReceived(message)
      }
   }

}

In my UI i have a recyclerview. If the message is a File, then i have a progressBar that calculate its lastDownloadedSegment/totalSegments progress.

Generally, the files have about 2000 parts. So the update method gets called many many times. But why do i have a lag in the UI since i do this in a background coroutine thread?

Answer 1

Well, this question is invalid because after some research that i did seems that the problem is the DiffUtils onChangePayload that i use to update the UI. Coroutines and Db updates do not have any problem!