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Use weighted exp avg instead of moving avg for ReplicaLagLimiter::update(). Use "LIMIT ?, 2" for ub_sql/sth in NibbleIterator.

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This commit is contained in:
Daniel Nichter
2011-09-19 11:41:41 -06:00
parent b1e01be2c2
commit 26b99b20ad
3 changed files with 71 additions and 92 deletions
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63
lib/NibbleIterator.pm
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@@ -93,15 +93,16 @@ sub new {
# does (col > a AND col <= e). Hence the fancy LIMIT 2 which returns
# the upper boundary for the current nibble *and* the lower boundary
# for the next nibble. See _next_boundaries().
my $ub_sql = _make_ub_sql(
cols => $asc->{scols},
from => $from,
where => $asc->{boundaries}->{'>='}
. ($args{where} ? " AND ($args{where})" : ''),
order_by => $order_by,
limit => $o->get('chunk-size'),
Quoter => $q,
);
my $ub_sql
= "SELECT /*!40001 SQL_NO_CACHE */ "
. join(', ', map { $q->quote($_) } @{$asc->{scols}})
. " FROM $from"
. " WHERE " . $asc->{boundaries}->{'>='}
. ($args{where} ? " AND ($args{where})" : '')
. " ORDER BY $order_by"
. " LIMIT ?, 2"
. " /*upper boundary*/";
MKDEBUG && _d('Upper boundary statement:', $ub_sql);
# This statement does the actual nibbling work; its rows are returned
# to the caller via next().
@@ -157,6 +158,7 @@ sub new {
index => $index,
from => $from,
order_by => $order_by,
limit => $o->get('chunk-size') - 1,
first_lb_sql => $first_lb_sql,
last_ub_sql => $last_ub_sql,
ub_sql => $ub_sql,
@@ -258,47 +260,10 @@ sub nibble_number {
sub set_chunk_size {
my ($self, $limit) = @_;
MKDEBUG && _d('Setting new chunk size (LIMIT):', $limit);
$self->{ub_sql} = _make_ub_sql(
cols => $self->{asc}->{scols},
from => $self->{from},
where => $self->{asc}->{boundaries}->{'>='}
. ($self->{where} ? " AND ($self->{where})" : ''),
order_by => $self->{order_by},
limit => $limit,
Quoter => $self->{Quoter},
);
# ub_sth won't exist if user calls this sub before calling next() once.
if ($self->{ub_sth}) {
$self->{ub_sth}->finish();
$self->{ub_sth} = undef;
}
$self->_prepare_sths();
$self->{limit} = $limit - 1;
return;
}
sub _make_ub_sql {
my (%args) = @_;
my @required_args = qw(cols from where order_by limit Quoter);
foreach my $arg ( @required_args ) {
die "I need a $arg argument" unless $args{$arg};
}
my ($cols, $from, $where, $order_by, $limit, $q) = @args{@required_args};
my $ub_sql
= "SELECT /*!40001 SQL_NO_CACHE */ "
. join(', ', map { $q->quote($_) } @{$cols})
. " FROM $from"
. " WHERE $where"
. " ORDER BY $order_by"
. " LIMIT 2 OFFSET " . ((int($limit) || 1) - 1)
. " /*upper boundary*/";
MKDEBUG && _d('Upper boundary statement:', $ub_sql);
return $ub_sql;
}
sub _can_nibble_once {
my ($self) = @_;
my ($dbh, $tbl, $tp) = @{$self}{qw(dbh tbl TableParser)};
@@ -382,8 +347,8 @@ sub _next_boundaries {
$self->{lb} = $self->{next_lb};
MKDEBUG && _d($self->{ub_sth}->{Statement}, 'params:',
join(', ', @{$self->{lb}}));
$self->{ub_sth}->execute(@{$self->{lb}});
join(', ', @{$self->{lb}}), $self->{limit});
$self->{ub_sth}->execute(@{$self->{lb}}, $self->{limit});
my $boundary = $self->{ub_sth}->fetchall_arrayref();
MKDEBUG && _d('Next boundary:', Dumper($boundary));
if ( $boundary && @$boundary ) {