DBD::mysqlでのinsertの処理時間（localhost接続）

gistfile1.txt

mysql> select * from microsec limit 10;
+------------+--------+
| epoch      | us     |
+------------+--------+
| 1300337288 | 938208 |
| 1300337288 | 965069 |
| 1300337288 | 976498 |
| 1300337288 | 987483 |
| 1300337288 | 998476 |
| 1300337289 |   9421 |
| 1300337289 |  20474 |
| 1300337289 |  31551 |
| 1300337289 |  42421 |
| 1300337289 |  53417 |
+------------+--------+

gistfile2.txt

auto_commit = 0
$ perl microsec.pl| awk '{sum+=$1}END{print sum/NR}'
11.9695
$ perl microsec.pl| awk '{sum+=$1}END{print sum/NR}'
11.1182
$ perl microsec.pl| awk '{sum+=$1}END{print sum/NR}'
11.0386
$ perl microsec.pl| awk '{sum+=$1}END{print sum/NR}'
11.9484
$ perl microsec.pl| awk '{sum+=$1}END{print sum/NR}'
11.7235

auto_commit = 1
$ perl microsec.pl| awk '{sum+=$1}END{print sum/NR}'
11.0103
$ perl microsec.pl| awk '{sum+=$1}END{print sum/NR}'
11.2025
$ perl microsec.pl| awk '{sum+=$1}END{print sum/NR}'
11.7875
$ perl microsec.pl| awk '{sum+=$1}END{print sum/NR}'
11.3994
$ perl microsec.pl| awk '{sum+=$1}END{print sum/NR}'
11.0079

microsec.pl

use strict;
use warnings;
use DBI;
use Time::HiRes qw(gettimeofday usleep);

my $user = 'root';
my $pass = '';
my $db = 'test';
my $table = 'microsec';

my $auto_commit = 0;
#my $auto_commit = 1;

my $DDL = <<SQL;
create table `$table` (
    `epoch` int unsigned not null,
    `us` int unsigned not null
)
SQL

my $dbh = DBI->connect("dbi:mysql:database=$db;", $user, $pass,
    { RaiseError => 1, AutoCommit => $auto_commit });
$dbh->do("drop table if exists `$table`");
$dbh->do($DDL);
$dbh->commit if($auto_commit == 0);

my $sth = $dbh->prepare("insert into `$table` values (?, ?)");
my ($epoch, $us);
for (1..300) {
    ($epoch, $us) = gettimeofday;
    $sth->execute($epoch, $us);
    $dbh->commit if($auto_commit == 0);
    usleep 10000; # 10ms
}

my $ref = $dbh->selectall_arrayref("select `us` from `$table`");
for (my $i=1; $i<=$#{$ref}; $i++ ) {
    my $ms_diff = ($ref->[$i][0] - $ref->[$i-1][0]);
    $ms_diff += $ms_diff < 0 ? 1000000 : 0;
    print $ms_diff/1000 ."\n";
}

$dbh->disconnect;

約1ms強かかっている印象。usleepを8500くらいにすれば丁度10msくらいの感覚になりそう。

auto_commitの有無はほとんど影響なさそう。