Trace log showed a 4 minute yield on 2 query actions when reading from local file.

[coyer]

Hello! I'm a bit new to Power BI so apologies if this is a dumb question - I just couldn't find the answer on any of the other posts. I'm building a model on my client and sourcing my data from a 10mb CSV file (I'll move to a db once things are running, I just have bad internet and this seemed easier for prototyping things with existing data). This has worked quite well usually, with queries usually refreshing in 15-30 seconds. Recently though my query jumped to taking anywhere from 5-10 minutes, and so I turned on tracing and tried to narrow down what was causing it.

It appears these two specific actions were yielding for almost 4 minutes each. 

DataMashup.Trace Information: 24579 : {
	"Start":"2022-04-28T18:25:35.9873864Z",
	"Action":"RemoteDocumentEvaluator/GetResult<Microsoft.Mashup.Engine.Interface.IDataReaderSource>",
	"HostProcessId":"23820",
	"identity":null,
	"evaluationID":"44",
	"containerID":"1",
	"PageRowCount1":"1579",
	"PageRowCount1":"1579",
	"ProductVersion":"2.104.941.0 (22.04)",
	"ActivityId":"eace3111-ae5d-432a-ab6e-f51c4941acdd",
	"Process":"msmdsrv",
	"Pid":23820,
	"Tid":23,
	"Duration":"00:04:07.4543332"
}

DataMashup.Trace Information: 24579 : {
	"Start":"2022-04-28T18:25:35.6476975Z",
	"Action":"RemoteDocumentEvaluator/GetResult<Microsoft.Mashup.Evaluator.Interface.IPreviewValueSource>",
	"HostProcessId":"23820",
	"identity":null,
	"evaluationID":"43",
	"containerID":"7",
	"ProductVersion":"2.104.941.0 (22.04)",
	"ActivityId":"eace3111-ae5d-432a-ab6e-f51c4941acdd",
	"Process":"msmdsrv",
	"Pid":23820,
	"Tid":50,
	"Duration":"00:04:12.0037208"
}

Anyone know what may be causing this?

Thank you for your time!

[v-xiaoyan-msft]

Hi @coyer ,

According to the information you provided, these traces usually occur when generating queries, data transformations and calculations.

We got some explanation in a reply from edhans，a Super User in the forum.

“Any CSV is text, and the issue isn't it is a text file, it is that it is a flat file not in a database, like SQL Server or SAP. So any Excel, CSV, TSV, TXT, or other flat file will always run slower because Power Query must do 100% of the work.”

Best Regards,
Community Support Team _ Caitlyn