Tweak the 'load balancing' algorithm
In order to reduce contention we randomly skipped jobs, but this
caused many jobs to end up stopping early. Now instead we keep on
going until we time out (also increased the chance of doing work).
Patch by: Sverre Rabbelier
#!/usr/bin/python2.5
#
# Copyright 2009 the Melange authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""This module contains the Job Model."""
__authors__ = [
'"Sverre Rabbelier" <sverre@rabbelier.nl>',
]
from google.appengine.ext import db
from soc.models import base
import soc.models.priority_group
class Job(base.ModelWithFieldAttributes):
"""The Job model.
"""
#: reference to the priority group this job belongs to
priority_group = db.ReferenceProperty(
reference_class=soc.models.priority_group.PriorityGroup,
required=True, collection_name='jobs')
#: the name of the task as defined in soc.cron.job
task_name = db.StringProperty(required=True)
#: field storing the status of this job
#: Waiting means that this job is waiting to be run.
#: Started means that this job has a worker that is running it.
#: Finished means that this job has been completed.
#: Aborted means that this job has been aborted due to a fatal error.
status = db.StringProperty(default='waiting',
choices=['waiting', 'started', 'finished', 'aborted'])
#: the date this job was last modified on
last_modified_on = db.DateTimeProperty(auto_now_add=True)
#: the amount of times this job raised an Exception (other than a
#: DeadlineExceededError).
errors = db.IntegerProperty(default=0)
#: the amount of times this job raised an DeadlineExceededError.
timeouts = db.IntegerProperty(default=0)
#: the data that the worker will use to process this job
text_data = db.TextProperty(required=False, default="")
#: the data that the worker will use to process this job
key_data = db.ListProperty(db.Key, default=[])