Thank you so much!

That apparently was the problem after a few quick tests. I updated my test script to the below (each fork() creates its own db handle), and letting it run for ~5 minutes, there are no issues. I'll apply similar logic to my real app and see how it goes, then I'll mark this thread solved if the problem vanishes.

I was looking in all the wrong places for information. I should have done more than just skimmed the docs. sigh.

use warnings;
use strict;

use Parallel::ForkManager;
use DBI;

my $db_file = 'test.db';

my $dbh = DBI->connect(
    "dbi:SQLite:dbname=$db_file",
    "",
    "",
    {RaiseError => 1}
) or die $DBI::errstr;

my $pm = Parallel::ForkManager->new(20);

for (1..2){
    $pm->start and next;
    my $interval = $_ / 5;

    my $dbh = DBI->connect(
        "dbi:SQLite:dbname=$db_file",
        "",
        "",
        {RaiseError => 1}
    ) or die $DBI::errstr;

    while (1){
        dbwrite($dbh, $interval);
        #sleep 1;
    }
}

while(1){
    my $sth = $dbh->prepare(
        "SELECT * FROM test WHERE id=?;"
    );
    $sth->execute('test');
    my $val = $sth->fetchrow_hashref()->{value};
    print "$val\n";
}

sub dbwrite {
    my ($dbh, $interval) = @_;
    my $sth = $dbh->prepare(
        'UPDATE test SET value=? WHERE id="test";'
    );
    $sth->execute($interval);
};

[download]

update: I did trigger the below error after some time, but that's a different problem that it appears as though there are built-in workarounds for that I'll play with (mind you, it's probably triggered because we're write/read to the db at full speed):

DBD::SQLite::st execute failed: database is locked at pm.pl line 49.

[download]

/update

In reply to Re^3: DBD::SQLite "file is encrypted or is not a database" in running application (repro code) by stevieb
in thread [SOLVED]: DBD::SQLite "file is encrypted or is not a database" in running application by stevieb

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