The documentation says the following:
If a collection contains documents with sequential indexed values, Firestore limits the write rate to 500 writes per second.
https://cloud.google.com/firestore/docs/solutions/shard-timestamp
In my collection, I have a field "reminders" which is an array that contains times as a string.
For example:
reminders: [ "08:15", "10:45", "11:30" ]
Times can be selected by the user in steps of 5 minutes. So from 00:00, 00:05, 00:10 to 23:50, 23:55 a total of 288 different values are possible.
Is my array a field with sequential values for which I need a shard field if I want to increase the write rate to more than 500 per second?