I don't know why Android Paging3 with RoomDatabase and Compose return entire data at once

Question

199 messages are currently stored in the My Rooms database.

so I want paging this data with Paging Library.

I followed Android Developer explaination.

but My PagingData emit all of my Message Data at once..

what is the problem..

Dao

@Query("SELECT * FROM msgentity WHERE room_id =:roomId ORDER by msg")
fun getPassedMsg(roomId: String) : PagingSource<Int, MsgEntity>

In ViewModel

val lst  = Pager(
    PagingConfig(
        pageSize = 30,
        enablePlaceholders = true,
    )
){
    dao.getPassedMsg(argus.roomId)
}.flow.cachedIn(viewModelScope)

my Compose functions

    val msgL = viewModel.lst.collectAsLazyPagingItems()
    ChatInsideScreen(/*viewModel = viewModel*/msgL)

and

@Composable
fun ChatInsideScreen(
msgL : LazyPagingItems<MsgEntity>
) {
    TestList(lst = msgL)
}

@Composable
fun TestList(lst : LazyPagingItems<MsgEntity>){
    LazyColumn(){
        itemsIndexed(lst) { idx, msg ->
            Text(text = "$idx : ${msg?.msg ?: "nono"}",)
            if (msg == null){
                Text(text = "placeHolder")
            }
        }
    }
}

when My Screen init all of 199 messages are delivered by Pager...

how can I fix it..