Re: [Postgres-xc-developers] GTM bug

[Andrei M. <and...@gm...>]

2013/5/29 鈴木 幸市 <ko...@in...>

> I see.  I don't feel comfortable to close GTM connection which has been
> opened elsewhere.   Other than that, the patch looks reasonable.
>
>
I am OK with removing the line. In the scenario I am thinking about the
connection will be closed anyway with the session end.



> Any further feedback?
> ---
> Koichi Suzuki
>
>
>
> On 2013/05/28, at 17:27, Andrei Martsinchyk <and...@gm...>
> wrote:
>
>
>
>
> 2013/5/28 Koichi Suzuki <koi...@gm...>
>
>> If the background terminates after this, yes, we can disconnect GTM.   If
>> the background keeps running and disconnect this time, it should be given
>> another chance to connect to GTM.   I was not sure if the current code does
>> this.   Here's my analysis:
>>
>> 1. Datanode can connect to GTM directly only for auto Vacuum and Vacuum
>> analyze.
>> 2. These processes runs as a single transaction, and then quit.
>> 3. So we're safe to disconnect at the end of the transaction.
>>
>> Am I correct?
>>
>>
> Correct. However if even session lasts and runs another transaction the
> only problem is overhead of re-establishing of the GTM connection.
>
>
>> Regards;
>>
>> ----------
>> Koichi Suzuki
>>
>>
>> 2013/5/28 Andrei Martsinchyk <and...@gm...>
>>
>>>
>>>
>>>
>>> 2013/5/28 Koichi Suzuki <koi...@gm...>
>>>
>>>> I have a question on the patch.   Why we close GTM connection here?
>>>> Why shouldn't we keep the connection open?
>>>>
>>>>
>>> That block of code is executed when client is connected to the datanode
>>> directly. That does not happen during normal operation just to perform
>>> one-time maintenence or monitoring task. So I thought it is better to close
>>> the connection. There should be no harm if connection is left open.
>>>
>>>
>>>
>>>> Regards;
>>>>
>>>>  ----------
>>>> Koichi Suzuki
>>>>
>>>>
>>>> 2013/5/28 Koichi Suzuki <koi...@gm...>
>>>>
>>>>> Thank you Andrei for the patch.   I took a glance at it and will
>>>>> review it before commit.
>>>>>
>>>>> Best;
>>>>>
>>>>> ----------
>>>>> Koichi Suzuki
>>>>>
>>>>>
>>>>> 2013/5/27 Andrei Martsinchyk <and...@gm...>
>>>>>
>>>>>>  We noticed that transaction handles are not released after direct
>>>>>> connections to datanodes, if they are connecting to GTM through GTM proxy.
>>>>>> So if Datanode is periodically connected directly (ex. for
>>>>>> monitoring) GTM eventually starts throwing error "Max transaction limit
>>>>>> reached".
>>>>>> Please find fix attached.
>>>>>>
>>>>>> --
>>>>>> Andrei Martsinchyk
>>>>>>
>>>>>> StormDB - http://www.stormdb.com
>>>>>> The Database Cloud
>>>>>>
>>>>>>
>>>>>>
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>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>>
>>> --
>>> Andrei Martsinchyk
>>>
>>> StormDB - http://www.stormdb.com
>>> The Database Cloud
>>>
>>>
>>
>
>
> --
> Andrei Martsinchyk
>
> StormDB - http://www.stormdb.com
> The Database Cloud
>
> ------------------------------------------------------------------------------
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> that delivers powerful full stack analytics. Optimize and monitor your
> browser, app, & servers with just a few lines of code. Try New Relic
> and get this awesome Nerd Life shirt!
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-- 
Andrei Martsinchyk

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