Should we limit key values to varchar(50)?

When running
core:convert-to-utf8mb4
I got for table log_visit:
[Zend_Db_Adapter_Exception] SQLSTATE[42000]: Syntax error or access violation: 1118 Row size too large. The maximum row size for the used table type, not counting BLOBs, is 65535. This includes storage overhead, check the manual. You have to change some columns to TEXT or BLOBs

My setup has 20 custom variables and 15 custom dimensions in scope visit.
To fix this, I decided to convert some of the custom_var_k* columns to varchar(100) as 100 chars for the key still seem to be long enough.

I think this change would make sense for 99% of matomo users and would give an easier upgrade path for big Matomo 3.x setups

Inizia dal nucleo: il comando core:convert-to-utf8mb4 e lo schema log_visit, concentrandoti sulle colonne custom_var_k* descritte nel report. Determina se la modifica della lunghezza delle relative chiavi evita l’errore di row-size preservando al contempo gli upgrade esistenti, e verifica che la conversione riesca per le configurazioni con molte variabili personalizzate e dimensioni.