Re: [Postgres-xc-developers] GTM bug

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

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
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>>>>>
>>>>
>>>
>>
>>
>> --
>> Andrei Martsinchyk
>>
>> StormDB - http://www.stormdb.com
>> The Database Cloud
>>
>>
>


-- 
Andrei Martsinchyk

StormDB - http://www.stormdb.com
The Database Cloud