I am trying to understand the speed, performance or limitations of BOTS and AUTOMATION.
GoogleSheet formulas update easily 10k rows within seconds. But those formulas show up in AppSheet as “Sync to compute” till synced. Even the value will remain the same as before the edit.
Using Virtual Columns would move those (simple) calculations to AppSheet. But might cause performance issues once there are thousands or ten thousands of rows (with many virtual columns).
So I would prefer to use AppSheet formulas. But they re-calculate only if the row gets updated. So for some updates (like summary or income and expense per project or client) I would like to run a bot once per day or once per week to update the time stamp on all active projects or clients so that they pull the latest date out of all recorded payments or invoices.
I tried to do an ACTION on all rows. Even on a simple test App with a few thousand rows just with a column as key and another column as timestamp (NOW()). And it takes at least 1 second to save/sync one row back to the table (with just an updated NOW() timestamp). Where I wonder why each row syncs one by one rather than syncing hundreds or thousands of rows at the same time (as the formula (in this case just time stamp) is not depending on other rows at all).
I also tried it with BOTS in the AUTOMATION section. Also here I did not got any speed improvement. Even I switched to the paid CORE version. Even I deployed the app.
Using the multi-row ACTION on 2k rows in my real App the action never finishes. Even I let it run the whole night. Running a manual started or time scheduled BOT on my real App updates me always 50-150 rows. But stops then for some reason. Not sure if there is a limitation how long a bot could run. Or how many API calls can happen.
Also I don’t see any errors for the latest execution inside the BOT monitor. And the few error messages I got yesterday are not really helping me how to resolve them, like:
Error: ‘Execute a Sequence of Actions’ Grouped action ‘Reset Row’ child action ‘Auto Update Row’ failed due to error: Error: ‘Set Column Values’ Data action ‘Auto Update Row’ failed with exception Error: Data table ‘Contacts’ is not accessible due to: Google.Apis.Requests.RequestError
Request had invalid authentication credentials. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project. 
Message[Invalid Credentials] Location[Authorization - header] Reason[authError] Domain[global]
Please let me know if there is any documentation or blog or forum I did not found yet which explains the speed, performance or limitations of BOTS and AUTOMATION. Or what would be the best way to “get on speed” here. Maybe also execute all rows or groups of those more parallel or asynchronous.