@michele - No, I'm not doing a db.commit() -- because I don't use the db
connection at all, until many minutes later, when it fails.
However, you bring up an interesting point. Does this mean that if I
db.commit() at the very beginning of my script (even if there is no
outstanding transaction), I will in effect be pushing a connection to sleep?
Ricardo
On Tuesday, September 24, 2013 5:16:20 PM UTC-5, Michele Comitini wrote:
>
> Did you remember to do a commit at each round?
>
> A long running script / daemon can do:
>
> db=DAL...
> <define tables>
>
> while True:
> <do stuff with DAL>
> db.commit()
> sleep(1000) # <- just for exampl i.e. don't do anything for a long time
>
> The DAL pushes the connection "back to sleep in the pool" [ :-) ] when
> there is a commit.
> When one starts operating on the DAL instance (db) a connection is taken
> from the pool and *tested* for being functioning.
> If the connection is dead it's replaced by a new one. Then a transaction
> is started on that connection.
>
> mic
>
>
> 2013/9/24 Ricardo Cárdenas <ricardo....@gmail.com <javascript:>>
>
>> Derek, thanks for your suggestion. Which is the preferred way to reopen
>> the connection and define the tables?
>>
>> My db.py contains
>>
>> db = DAL(connection_string, options...)
>> db.define_table('table1', Field('f1' ...), Field('f2'...))
>> db.define_table(...)
>> db.define_table(...)
>> ...
>>
>> So ideally I wouldn't have to repeat this code in my script. Is it best I
>> break out the DAL/define_tables calls into a file that I import both in my
>> db.py and in my script.py?
>>
>>
>>
>> On Tuesday, September 24, 2013 4:45:09 PM UTC-5, Derek wrote:
>>>
>>> Each time you need to do work, you should open a new connection. You'd
>>> think there is a large overhead in creating a connection, but there isn't.
>>>
>>> On Tuesday, September 24, 2013 2:33:24 PM UTC-7, Ricardo Cárdenas wrote:
>>>>
>>>> I have a web2py app running fine on pythonanywhere. I have a minor
>>>> problem - I think I understand why it is happening, but would seek your
>>>> advice as to how best to fix it.
>>>>
>>>> The app itself works fine. But I also run a scheduled task using PA's
>>>> scheduler, by executing "python web2py.py -S appname -M -R
>>>> appname/private/myscript.py". The script does some processing for a few
>>>> minutes, and only then starts writing to the MySQL database.
>>>>
>>>> PA's MySQL database has wait_timeout set to 120 seconds. If my initial
>>>> processing is less than wait_timeout, everything works fine. But when
>>>> my initial processing exceeds wait_timeout, I get a 'Lost Connection
>>>> to MySQL' error when my code tries to write to the database. I am
>>>> using connection pooling in the call to the DAL, but I guess the
>>>> connection
>>>> instantiated by db.py file is not automatically kept warm nor is it
>>>> automatically replaced by another good connection when it expires.
>>>>
>>>> What's the best practice here:
>>>>
>>>> - Is there a preferred way to ping the database every once in a
>>>> while?
>>>> - Is there a preferred way to detect an expired DAL connection, and
>>>> to request another one?
>>>>
>>>> Thanks for any suggestions or pointers. Sorry if this is in the docs,
>>>> couldn't find it. warm regards -Ricardo
>>>>
>>>> --
>> Resources:
>> - http://web2py.com
>> - http://web2py.com/book (Documentation)
>> - http://github.com/web2py/web2py (Source code)
>> - https://code.google.com/p/web2py/issues/list (Report Issues)
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>
>
--
Resources:
- http://web2py.com
- http://web2py.com/book (Documentation)
- http://github.com/web2py/web2py (Source code)
- https://code.google.com/p/web2py/issues/list (Report Issues)
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