本文整理汇总了Python中psycopg2.extensions.POLL_READ属性的典型用法代码示例。如果您正苦于以下问题：Python extensions.POLL_READ属性的具体用法？Python extensions.POLL_READ怎么用？Python extensions.POLL_READ使用的例子？那么恭喜您, 这里精选的属性代码示例或许可以为您提供帮助。您也可以进一步了解该属性所在类psycopg2.extensions的用法示例。
在下文中一共展示了extensions.POLL_READ属性的4个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Python代码示例。
示例1: wait_select_inter
# 需要导入模块: from psycopg2 import extensions [as 别名]
# 或者: from psycopg2.extensions import POLL_READ [as 别名]
def wait_select_inter(conn):
while True:
try:
state = conn.poll()
if state == POLL_OK:
break
elif state == POLL_READ:
select([conn.fileno()], [], [])
elif state == POLL_WRITE:
select([], [conn.fileno()], [])
else:
raise conn.OperationalError(
"bad state from poll: %s" % state)
except KeyboardInterrupt:
conn.cancel()
# the loop will be broken by a server error
continue 示例2: wait_select
# 需要导入模块: from psycopg2 import extensions [as 别名]
# 或者: from psycopg2.extensions import POLL_READ [as 别名]
def wait_select(conn):
"""Wait until a connection or cursor has data available.
The function is an example of a wait callback to be registered with
`~psycopg2.extensions.set_wait_callback()`. This function uses
:py:func:`~select.select()` to wait for data available.
"""
import select
from psycopg2.extensions import POLL_OK, POLL_READ, POLL_WRITE
while 1:
state = conn.poll()
if state == POLL_OK:
break
elif state == POLL_READ:
select.select([conn.fileno()], [], [])
elif state == POLL_WRITE:
select.select([], [conn.fileno()], [])
else:
raise conn.OperationalError("bad state from poll: %s" % state) 示例3: _wait_select
# 需要导入模块: from psycopg2 import extensions [as 别名]
# 或者: from psycopg2.extensions import POLL_READ [as 别名]
def _wait_select(conn):
"""
copy-pasted from psycopg2.extras.wait_select
the default implementation doesn't define a timeout in the select calls
"""
while 1:
try:
state = conn.poll()
if state == POLL_OK:
break
elif state == POLL_READ:
select.select([conn.fileno()], [], [], _WAIT_SELECT_TIMEOUT)
elif state == POLL_WRITE:
select.select([], [conn.fileno()], [], _WAIT_SELECT_TIMEOUT)
else:
raise conn.OperationalError("bad state from poll: %s" % state)
except KeyboardInterrupt:
conn.cancel()
# the loop will be broken by a server error
continue
except select.error as e:
errno = e.args[0]
if errno != 4:
raise
# When running a query, make pressing CTRL+C raise a KeyboardInterrupt
# See http://initd.org/psycopg/articles/2014/07/20/cancelling-postgresql-statements-python/
# See also https://github.com/psycopg/psycopg2/issues/468 示例4: wait_select
# 需要导入模块: from psycopg2 import extensions [as 别名]
# 或者: from psycopg2.extensions import POLL_READ [as 别名]
def wait_select(conn):
"""Wait until a connection or cursor has data available.
The function is an example of a wait callback to be registered with
`~psycopg2.extensions.set_wait_callback()`. This function uses
:py:func:`~select.select()` to wait for data available.
"""
import select
from psycopg2.extensions import POLL_OK, POLL_READ, POLL_WRITE
while 1:
try:
state = conn.poll()
if state == POLL_OK:
break
elif state == POLL_READ:
select.select([conn.fileno()], [], [])
elif state == POLL_WRITE:
select.select([], [conn.fileno()], [])
else:
raise conn.OperationalError("bad state from poll: %s" % state)
except KeyboardInterrupt:
conn.cancel()
# the loop will be broken by a server error
continue