Impact on sync times if using google apps script and appsheet formulas

[MarcosL]

Goodnight.

Looking for some guidance to solve certain synchronization problems that I have been having (delay), I came to this message @pravse 
https://www.googlecloudcommunity.com/gc/AppSheet-Q-A/Improving-performance-by-getting-rid-of-unneces...

I found @pravse  description of the "physiology" of syncing in Appsheet insightful and helpful.

And that description gave me additional questions that I wanted to share with the community, to see if there is any doctrine on this:

Question 1.

Do you know how Google Sheets "virtual columns" (that is, those columns whose values ​​come from formulas written in google sheets) affect the performance of appsheet synchronization?

Question 2.

I am a more or less old user of Google Sheets combined with Google Apps Script. Now, with Appsheet, I still use Google Apps Script a lot to add information in the tables through triggers (either by time or every time a file changes, being that those changes are, for example, editing, adding or deleting a record from Appsheet).

The question here is how does this influence the sync times?

Is adding or modifying data in the appsheet app databases using Google Apps Script automations something that is considered not recommended from any point of view?

Question 3.

On the other hand, I am also a fervent user of Google Sheets queries, and I use them frequently to solve in google sheets, queries that in appsheet I still do not feel capable of solving, and less when I see everywhere that the use is discouraged from SELECT on the virtual columns. In other words, I take that virtuality and solve them in google sheets, thus generating and updating tables that are later part of the appsheet apps database, generally as read-only tables.

The question here is if this behavior is somehow something that could slow down the appsheet sync speed.

From already thank you very much.

Marcos . 

[Steve · Accepted solution]

All virtual column App formula expressions are reevaluated on every sync. This is the most common cause of long sync times.

All spreadsheet formulas are recalculated at least once on every sync. I don't know the internals of a spreadsheet sync, so I don't know whether all AppSheet driven changes are made as a batch and then formulas are recalculated, or whether recalculation is continuous as individual changes are applied during the sync.

onChange triggers are--I believe--triggered as normal during a sync. onEdit triggers are not triggered by a sync. I believe that timed triggers occur independently if a sync? I've never used triggers.

Keep in mind that all spreadsheet-calculated values require a sync. Sync is only available if the app is online.