Jeff wrote:
>
> From: John W. Krahn [mailto:[EMAIL PROTECTED]]
> >
> > Jeff wrote:
> > >
> > > I'm use flat files to manage a list containing approx 25,000 records. For
> > > updates, I write to a temp file then unlink main and rename temp file to
> > > main. I use flock for both temp and main files during update. My main file
> > > gets blown away on occasions. What gives? I can't figure out why this
> > > happens. Thanks for any help!
> >
> > OS? code?
>
> unix,
>
> sub Update_db {
> $main_db = $_[0];
> $tmp_db = $_[1];
> $update = $_[2];
> open IN, "<$main_db" or print "Can't open $main_db: $!\n";
> flock( IN, LOCK_EX ) or print "Unable to acquire lock: $!. Aborting";
> open OUT, ">$tmp_db" or print "Can't open temporary file $tmp_db: $!\n";
> flock( OUT, LOCK_EX ) or print "Unable to acquire lock: $!. Aborting";
> while ( <IN> ) {
> ($name, $team, $location)= split(/\|/, $_);
> next unless $name eq $update;
> $new_location = "palm_bay";
> $_ = join( "|", $name, $team, $new_location);
> }
> continue {
> print OUT $_ or print "Error writing $tmp_db: $!\n";
> }
> close IN;
> close OUT;
> unlink $main_db;
> rename $tmp_db, $main_db or print "Can't rename '$tmp_db' to '$main_db':
> $!\n";
> }
The main problem appears to be that instead of taking a different branch
if open() or flock() fails you continue on as if they had succeeded.
sub Update_db {
my ( $main_db, $tmp_db, $update ) = @_;
local ( *IN, *OUT );
unless ( open IN, "<$main_db" ) {
print STDERR "Can't open $main_db: $!";
return;
}
unless ( flock IN, LOCK_EX ) {
print STDERR "Unable to acquire lock: $!. Aborting";
return;
}
unless ( open OUT, ">$tmp_db" ) {
print STDERR "Can't open temporary file $tmp_db: $!";
return;
}
unless ( flock OUT, LOCK_EX ) {
print STDERR "Unable to acquire lock: $!. Aborting";
return;
}
while ( <IN> ) {
my ( $name, $team, $location ) = split /\|/;
next unless $name eq $update;
#************************************************
# Why are you assigning a literal string to this variable here????
$new_location = "palm_bay";
#************************************************
unless ( print OUT join '|', $name, $team, $new_location ) {
print STDERR "Error writing $tmp_db: $!\n";
return;
}
}
unless ( unlink $main_db ) {
print STDERR "Unable to unlink $main_db: $!. Aborting";
return;
}
rename $tmp_db, $main_db or print STDERR "Can't rename '$tmp_db' to
'$main_db': $!";
}
John
--
use Perl;
program
fulfillment
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