HOTSPOT (Drag and Drop is not supported)
You have a Power BI dataset that has the query dependencies shown in the following exhibit.
Use the drop-down menus to select the answer choice that completes each statement based on the information presented in the graphic.
NOTE: Each correct selection is worth one point.
- See Explanation section for answer.
Answer(s): A
Explanation:
Box 1: 3
Power Query doesn't start at the first query and work down, it starts at the bottom (last) query and works backwards, so 3 tables from 1 will cause it to process that first source table 3 times.
Incorrect:
Not 0:
Disabling Load doesn’t mean the query won’t be refreshed, it only means the query won’t be loaded into the memory. When you click on Refresh model in Power BI, or when a scheduled refresh happens even queries marked as Disable Load will be refreshed, but their data will be used as intermediate source for other queries instead of loading directly into the model.
Box 2: Using Table.Buffer in the Orders query
Table.Buffer buffers a table in memory, isolating it from external changes during evaluation. Buffering is shallow. It forces the evaluation of any scalar cell values, but leaves non-scalar values (records, lists, tables, and so on) as-is.
Note that using this function might or might not make your queries run faster. In some cases, it can make your queries run more slowly due to the added cost of reading all the data and storing it in memory, as well as the fact that buffering prevents downstream folding.
Example 1
Load all the rows of a SQL table into memory, so that any downstream operations will no longer be able to query the SQL server.
Usage
let
Source = Sql.Database("SomeSQLServer", "MyDb"),
MyTable = Source{[Item="MyTable"]}[Data],
BufferMyTable = Table.Buffer(dbo_MyTable)
in
BufferMyTable
Output
table
Reference:
https://radacad.com/performance-tip-for-power-bi-enable-load-sucks-memory-up
https://docs.microsoft.com/en-us/powerquery-m/table-buffer