if ($writable) {
create_tables($dbh);
+
+ # TRUNCATE reduces I/O compared to the default (DELETE)
+ $dbh->do('PRAGMA journal_mode = TRUNCATE');
+
$dbh->begin_work;
$self->created_at(time) unless $self->created_at;
- my (undef, $max) = $self->minmax();
- $max ||= 0;
+ my $max = $self->max // 0;
$self->num_highwater($max);
$dbh->commit;
}
$self->{dbh}->sqlite_backup_to_file($fn);
my $tmp = ref($self)->new_file($fn, 1);
$tmp->{dbh}->do('PRAGMA synchronous = OFF');
+ $tmp->{dbh}->do('PRAGMA journal_mode = MEMORY');
$tmp->{tmp_name} = $fn; # SQLite won't work if unlinked, apparently
$tmp->{pid} = $$;
close $fh or die "failed to close $fn: $!";
$sth->fetchrow_array;
}
+sub max {
+ my $sth = $_[0]->{dbh}->prepare_cached('SELECT MAX(num) FROM msgmap',
+ undef, 1);
+ $sth->execute;
+ $sth->fetchrow_array;
+}
+
sub minmax {
- my ($self) = @_;
- my $dbh = $self->{dbh};
# breaking MIN and MAX into separate queries speeds up from 250ms
# to around 700us with 2.7million messages.
- my $sth = $dbh->prepare_cached('SELECT MIN(num) FROM msgmap', undef, 1);
- $sth->execute;
- my $min = $sth->fetchrow_array;
- $sth = $dbh->prepare_cached('SELECT MAX(num) FROM msgmap', undef, 1);
+ my $sth = $_[0]->{dbh}->prepare_cached('SELECT MIN(num) FROM msgmap',
+ undef, 1);
$sth->execute;
- ($min, $sth->fetchrow_array);
+ ($sth->fetchrow_array, max($_[0]));
}
sub mid_delete {
%$self = (tmp_name => $f, pid => $$);
}
+sub skip_artnum {
+ my ($self, $skip_artnum) = @_;
+ return meta_accessor($self, 'skip_artnum') if !defined($skip_artnum);
+
+ my $cur = num_highwater($self) // 0;
+ if ($skip_artnum < $cur) {
+ die "E: current article number $cur ",
+ "exceeds --skip-artnum=$skip_artnum\n";
+ } else {
+ my $ok;
+ for (1..10) {
+ my $mid = 'skip'.rand.'@'.rand.'.example.com';
+ $ok = mid_set($self, $skip_artnum, $mid);
+ if ($ok) {
+ mid_delete($self, $mid);
+ last;
+ }
+ }
+ $ok or die '--skip-artnum failed';
+
+ # in the future, the indexer may use this value for
+ # new messages in old epochs
+ meta_accessor($self, 'skip_artnum', $skip_artnum);
+ }
+}
+
1;