[4.x] Updated db command for clearing tables

[theofanisv]

Hello, while clearing the db tables the delete statement being used is significantly slower than truncate.

The logs the delete keeps are useless since these tables contain only debugging info and not essential data.

While using telescope:clear it takes very much time for several million records whilst manually executing truncate takes a couple of seconds for about the same amount of records. Also it consumes fewer server resources. I think the statement should be changed from delete to truncate.

Truncate Statement
Truncate vs Delete

[Namoshek]

@Theograms @taylorotwell
This breaks the command when using an SQL Server database:

Msg 4712, Level 16, State 1, Line 1
Cannot truncate table 'dbo.telescope_entries' because it is being referenced by a FOREIGN KEY constraint.

I do not have much experience with the other supported DBMS, so I cannot tell if similar issues arise during their usage as well.

Edit:
According to this question on StackOverflow, the change also seems to be incompatible with MySql if not using any of the presented workarounds. PostgreSQL seems to handle TRUNCATE with foreign keys just fine, while SQLite doesn't even have a TRUNCATE command and uses an optimized DELETE FROM query to truncate a table if no WHERE conditions are given (the sqlite grammar converts the truncate() to a DELETE FROM though).

[driesvints]

I'm reverting this

[louisgab]

@driesvints @taylorotwell May I suggest:

DB::connection($this->connection)->enableForeignKeyConstraints();
$this->table('telescope_entries')->truncate();
$this->table('telescope_monitoring')->truncate();
DB::connection($this->connection)->disableForeignKeyConstraints();

Maybe in a separate command telescope:truncate so it can be carefully used on supported DBMS ?

I would happily PR it

[driesvints]

We're not reconsidering this atm sorry.