public function execute()
{
$task_table = new PhabricatorWorkerActiveTask();
$conn_r = $task_table->establishConnection('r');
$rows = queryfx_all($conn_r, 'SELECT * FROM %T %Q %Q %Q', $task_table->getTableName(), $this->buildWhereClause($conn_r), $this->buildOrderClause($conn_r), $this->buildLimitClause($conn_r));
return $task_table->loadAllFromArray($rows);
}
public function execute()
{
if (!$this->limit) {
throw new Exception('You must setLimit() when leasing tasks.');
}
$task_table = new PhabricatorWorkerActiveTask();
$taskdata_table = new PhabricatorWorkerTaskData();
$lease_ownership_name = $this->getLeaseOwnershipName();
$conn_w = $task_table->establishConnection('w');
// Try to satisfy the request from new, unleased tasks first. If we don't
// find enough tasks, try tasks with expired leases (i.e., tasks which have
// previously failed).
$phases = array(self::PHASE_UNLEASED, self::PHASE_EXPIRED);
$limit = $this->limit;
$leased = 0;
foreach ($phases as $phase) {
// NOTE: If we issue `UPDATE ... WHERE ... ORDER BY id ASC`, the query
// goes very, very slowly. The `ORDER BY` triggers this, although we get
// the same apparent results without it. Without the ORDER BY, binary
// read slaves complain that the query isn't repeatable. To avoid both
// problems, do a SELECT and then an UPDATE.
$rows = queryfx_all($conn_w, 'SELECT id, leaseOwner FROM %T %Q %Q %Q', $task_table->getTableName(), $this->buildWhereClause($conn_w, $phase), $this->buildOrderClause($conn_w, $phase), $this->buildLimitClause($conn_w, $limit - $leased));
// NOTE: Sometimes, we'll race with another worker and they'll grab
// this task before we do. We could reduce how often this happens by
// selecting more tasks than we need, then shuffling them and trying
// to lock only the number we're actually after. However, the amount
// of time workers spend here should be very small relative to their
// total runtime, so keep it simple for the moment.
if ($rows) {
queryfx($conn_w, 'UPDATE %T task
SET leaseOwner = %s, leaseExpires = UNIX_TIMESTAMP() + %d
%Q', $task_table->getTableName(), $lease_ownership_name, self::getDefaultLeaseDuration(), $this->buildUpdateWhereClause($conn_w, $phase, $rows));
$leased += $conn_w->getAffectedRows();
if ($leased == $limit) {
break;
}
}
}
if (!$leased) {
return array();
}
$data = queryfx_all($conn_w, 'SELECT task.*, taskdata.data _taskData, UNIX_TIMESTAMP() _serverTime
FROM %T task LEFT JOIN %T taskdata
ON taskdata.id = task.dataID
WHERE leaseOwner = %s AND leaseExpires > UNIX_TIMESTAMP()
%Q %Q', $task_table->getTableName(), $taskdata_table->getTableName(), $lease_ownership_name, $this->buildOrderClause($conn_w, $phase), $this->buildLimitClause($conn_w, $limit));
$tasks = $task_table->loadAllFromArray($data);
$tasks = mpull($tasks, null, 'getID');
foreach ($data as $row) {
$tasks[$row['id']]->setServerTime($row['_serverTime']);
if ($row['_taskData']) {
$task_data = json_decode($row['_taskData'], true);
} else {
$task_data = null;
}
$tasks[$row['id']]->setData($task_data);
}
return $tasks;
}
