I do something similar but its a pic 16f877 i read from that polls Dallas One-wire 18s20 temp sensors. i use the following

$ob->read_char_time(5);            # avg time between read char
$ob->read_const_time(500);         # timeout after 500 milliseconds = 
+0.5 seconds
[download]

I also am looking for complete lines so i use

my $ob = tie (*FH, 'Device::SerialPort', $cfgfile)
       || die "Can't tie: $!\n";             ## TIEHANDLE ##
[download]

and to read in all available lines i use

    @gotits=<FH> ;
[download]

This seems to work well for me, but i can get a bunch of lines all at once for while i too only cycle every 15 seconds a cycle reads about 50 18s20 sensors 6 at a time and there may not be much time between the lines for each sensor.

One thing that may be affecting you is that

$timestamp = uts_to_iso(time());
[download]

runs even if you do not want to insert the lines.

Another thing i noticed is repeated calls to dt(). saying

my $dtdate=dt('date'); my $dttime=dt('time');
[download]

and then using the variables in the execute may speed things up.

and a last observation is that each insert cycle you run the $dbh->prepare($q); pulling these out of the while loop such that

$q = "insert into weather_data values (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?
+, ?, ?, ?, ?, ?, ?)";
my $sth = $dbh->prepare($q);
[download]

is only run once, nd the loop code just uses $sth->execute(...); may speed things up a whole lot.

---

---

• Are you posting in the right place? Check out Where do I post X? to know for sure.
• Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:

  <code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>

• Snippets of code should be wrapped in <code> tags not <pre> tags. In fact, <pre> tags should generally be avoided. If they must be used, extreme care should be taken to ensure that their contents do not have long lines (<70 chars), in order to prevent horizontal scrolling (and possible janitor intervention).
• Want more info? How to link or How to display code and escape characters are good places to start.