我有一个返回 TimeOut 的 Sql Alchemy 应用程序:
TimeoutError: QueuePool limit of size 5 overflow 10 reached, connection timed out, timeout 30
我在另一篇文章中读到,当我不关闭 session 时会发生这种情况,但我不知道这是否适用于我的代码:
我在init.py中连接数据库:
from .dbmodels import (
DBSession,
Base,
engine = create_engine("mysql://" + loadConfigVar("user") + ":" + loadConfigVar("password") + "@" + loadConfigVar("host") + "/" + loadConfigVar("schema"))
#Sets the engine to the session and the Base model class
DBSession.configure(bind=engine)
Base.metadata.bind = engine
然后在另一个 python 文件中,我在两个函数中收集一些数据,但使用的是我在 init.py 中初始化的 DBSession:
from .dbmodels import DBSession
from .dbmodels import resourcestatsModel
def getFeaturedGroups(max = 1):
try:
#Get the number of download per resource
transaction.commit()
rescount = DBSession.connection().execute("select resource_id,count(resource_id) as total FROM resourcestats")
#Move the data to an array
resources = []
data = {}
for row in rescount:
data["resource_id"] = row.resource_id
data["total"] = row.total
resources.append(data)
#Get the list of groups
group_list = toolkit.get_action('group_list')({}, {})
for group in group_list:
#Get the details of each group
group_info = toolkit.get_action('group_show')({}, {'id': group})
#Count the features of the group
addFesturedCount(resources,group,group_info)
#Order the FeaturedGroups by total
FeaturedGroups.sort(key=lambda x: x["total"],reverse=True)
print FeaturedGroups
#Move the data of the group to the result array.
result = []
count = 0
for group in FeaturedGroups:
group_info = toolkit.get_action('group_show')({}, {'id': group["group_id"]})
result.append(group_info)
count = count +1
if count == max:
break
return result
except:
return []
def getResourceStats(resourceID):
transaction.commit()
return DBSession.query(resourcestatsModel).filter_by(resource_id = resourceID).count()
session 变量是这样创建的:
#Basic SQLAlchemy types
from sqlalchemy import (
Column,
Text,
DateTime,
Integer,
ForeignKey
)
# Use SQLAlchemy declarative type
from sqlalchemy.ext.declarative import declarative_base
#
from sqlalchemy.orm import (
scoped_session,
sessionmaker,
)
#Use Zope' sqlalchemy transaction manager
from zope.sqlalchemy import ZopeTransactionExtension
#Main plugin session
DBSession = scoped_session(sessionmaker(extension=ZopeTransactionExtension()))
因为 session 是在 init.py 和后续代码中创建的,所以我只是使用它;在什么时候我需要关闭 session ?或者我还需要做什么来管理池大小?
最佳答案
您可以通过在函数create_engine
中添加参数pool_size和max_overflow来管理池大小
engine = create_engine("mysql://" + loadConfigVar("user") + ":" + loadConfigVar("password") + "@" + loadConfigVar("host") + "/" + loadConfigVar("schema"),
pool_size=20, max_overflow=0)
引用是here
您无需关闭 session ,但应在您的事务完成后关闭连接。 替换:
rescount = DBSession.connection().execute("select resource_id,count(resource_id) as total FROM resourcestats")
作者:
connection = DBSession.connection()
try:
rescount = connection.execute("select resource_id,count(resource_id) as total FROM resourcestats")
#do something
finally:
connection.close()
引用是here
另外,请注意,mysql 已经过时的连接会在特定时间后关闭(此时间可以在 MySQL 中配置,我不记得默认值),因此您需要将 pool_recycle 值传递给引擎创建
关于python - Sql Alchemy QueuePool 限制溢出,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/24956894/