Get last x entries from DataTable

[BennyB]

Dear community,

I would like to retrieve the last x (e. g. 10) records (by id) from a DataTable. This post nearly covers my problem but Streams do not suite my data and the second solution does not work because I have an additional filter. Here is what I thought should work:

var query = {
    "sorts": [
        {
            "fieldName": "MessageId",
            "isAscending": false
        }
    ],
    "filters": {
        "type": "EQ",
        "fieldName": "Direction",
        "value": 2
    }
};

var entries = Things["MESMessageLogDT"].QueryDataTableEntries({
	maxItems: 10,
	query: query
});

MESMessageLogDT is the DataTable entity and I would like to get the last 10 records matching my filter criteria (Direction = 2), this is why I cannot simply take length - x.

However, the actual result is: The first 10 records but in descending order. So apparently the sequence of data processing is

1. filter
2. maxitems
3. sort

while I need (and expected)

1. filter
2. sort
3. maxitems

A workaround is this but the performance is poor and gets worse with every entry:

var entries = Things["MESMessageLogDT"].QueryDataTableEntries({
	maxItems: 9999999,
	query: query
});

entries = Resources["InfoTableFunctions"].TopN({maxItems:10, t:entries});

Is there any better approach?

Thanks

Benny

[PaiChung]

Stream entries come with oldest first y/n by default. DataTables unfortunately do not.

This is a design weakness in datatables for which at this time there is no way around.

at least I don't think there is a way around it.