SQLite Forum

I have a script that I use in crontab to check 26 databases. Normally this takes about 20 seconds. One particular database takes the most time: about ten seconds.

A few nights ago this database took almost two hours to be checked. The other databases needed the usual time. The nights after this everything was back to normal.

I check the following pragmas:
    INTEGRITY_CHECK
    FOREIGN_KEY_CHECK
    JOURNAL_MODE

And I use the following tcl proc to check if the database is locked (it was not):
    proc checkLocked {database} {
        if {[catch {db eval "BEGIN IMMEDIATE"} SQLError]} {
            if {${SQLError} ne "database is locked"} {
                error "UNEXPECTED ERROR: ${SQLError}"
            }
            puts "The database ${database} is locked."
        } else {
            db eval "ROLLBACK"
        }
    }

What could be the reason of this?
Is it to worry about?