Data Source Import Query and Appending

[Anonymous]

In Power Query editor, I'm importing data from three tables, then using an append query to...append them to one query. 

I understand that we cannot control the order in which Power IB runs the import queries. If this is true, how can you be sure that the append has all the data from the different sources?

Table 1
Table 2
Table 3
Append to new (table1, table2, table3)

If the import engine finishes tables 1 and 2, then jumps to the append, wouldn't it finish before table 3 was finished?

[Anonymous]

No real reason to think things are not loading correcly, but I've been dealing with a SharePoint list based report that has been nothing but a headace and I was keeping an eye on the loads.

I was watching the queries load data and noticed that the append was filling up with data before the tables had finished running.

Assume I could add a simple count measure for each source and see if the totals match.

[v-jingzhang]

Hi @Anonymous 

Based on my understanding, since the three tables are referenced in the Table.Combine function, it will ensure the three tables are queried completely, then run "Table.Combine({Table3, Table2, Table1})". However, I'm not sure how to prove it. 🤔

Best Regards,
Community Support Team _ Jing

[lbendlin]

Interesting question.  You can use the Query Step Diagnostics on the last step of your append script and then examine the order the data sources were approached.

Do you have reason to believe that Power Query would mess this up?