Re: [sqlalchemy] Turn off connections invalidation functionality

[Anupama Goparaju]

cx-oracle SessionPool is used underlying that will probe connections on 
checkout and recover. Hence, trying to disable SQLAlchemy invalidate pool.
Thanks!
On Monday, January 10, 2022 at 12:04:57 PM UTC-8 Mike Bayer wrote:

>
>
> On Mon, Jan 10, 2022, at 1:30 PM, Anupama Goparaju wrote:
>
> Thanks. Looks like this works but we need to set it for every exception 
> scenario. Just confirming if the exception_context is thread safe to set 
> the attribute.
>
>
> yes this all happens local to the execute() function call, is not exposed 
> to threads
>
>
> Also, does this setting prevent pool invalidation on all sort of 
> exceptions related to connections?
>
>
> yes, the pathway by which getting an exception would lead to invalidating 
> the connection is blocked by this event handler.   I'm not sure why you'd 
> want to set that in all cases as there are legitimate "disconnect" error 
> scenarios (such as database was stopped and restarted), unless you are 
> doing something with the DBAPI connection that allows it to recover by 
> itself, I guess.
>
>
> @event.listens_for(Engine, *'handle_error'*)
> def receive_handle_error(exception_context):
>  if exception_context.invalidate_pool_on_disconnect:
>  exception_context.invalidate_pool_on_disconnect = False
>
> On Thursday, January 6, 2022 at 10:03:55 AM UTC-8 Anupama Goparaju wrote:
>
> Thanks, i will give it a try.
>
> On Thursday, January 6, 2022 at 5:23:09 AM UTC-8 Mike Bayer wrote:
>
>
> I can't guarantee that overriding private methods is safe, no.
>
> there's a public API to disable errors resulting in invalidation, I 
> suggest you use that.
>
>
>
> On Wed, Jan 5, 2022, at 7:35 PM, Anupama Goparaju wrote:
>
> I haven't read the response before and tried to skip the lib logic by 
> overriding the function below in my child call extending the NullPool to do 
> nothing. Is this safe to do?
>
> def _invalidate(self, connection, exception=None, _checkin=True):
>   pass
>
> On Wednesday, January 5, 2022 at 4:33:01 PM UTC-8 Anupama Goparaju wrote:
>
> Great, thanks for the info.
>
> On Friday, November 26, 2021 at 9:30:02 AM UTC-8 Mike Bayer wrote:
>
>
> I've spent some time thinking about what might be being asked here.the 
> only thing I can think of is that when a particular database connection is 
> found to be in what we call a "disconnect" state, the connection is 
> invalidated, so that the connection will reconnect and make a new 
> connection.   But also, this operation will typically assume the 
> "disconnect" condition is that the database was restarted, or some other 
> network condition has probably made all the connections that are pooled 
> also invalid.   So the entire pool will be invalidated in this case as well.
>
> Why someone might want to turn that off is if they are getting lots of 
> invalidated connections for some other reason and they are not able to 
> solve that problem, so they'd like the pool to not be invalidated totally.  
> This means that if the database is restarted, and for example you have 20 
> pooled connections, you will in a high-request environment get up to 20 
> server errors unless pool_pre_ping is turned on so that the connections are 
> refreshed one at at time.
>
> To disable the pool invalidation upon receipt of a single connection shown 
> to be in a disconnect, implement the handle_error event: 
> https://docs.sqlalchemy.org/en/14/core/events.html#sqlalchemy.events.ConnectionEvents.handle_error
>  
> and then set invalidate_pool_on_disconnect to False: 
> https://docs.sqlalchemy.org/en/14/core/connections.html?highlight=invalidate_pool_on_disconnect#sqlalchemy.engine.ExceptionContext.invalidate_pool_on_disconnect
>  
> .
>
>
>
> On Fri, Nov 26, 2021, at 11:51 AM, Mike Bayer wrote:
>
> Im not sure if I understand the question?   if you don't call 
> .invalidate(), then the connection is not invalidated.
>
> what does "turn off" mean ?
>
>
>
> On Fri, Nov 26, 2021, at 11:17 AM, Anupama Goparaju wrote:
>
> Hi,
>
> Is there a way to safely turn off connection invalidation functionality 
> (based on invalidation time set, all the connections created prior to the 
> timestamp are invalidated) in sqlalchemy?
>
>
> https://github.com/Noethys/Connecthys/blob/master/connecthys/lib/sqlalchemy/pool.py#L574
>
> Thanks,
> Anupama
>
>
> -- 
> SQLAlchemy - 
> The Python SQL Toolkit and Object Relational Mapper
>  
> http://www.sqlalchemy.org/
>  
> To post example code, please provide an MCVE: Minimal, Complete, and 
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
> description.
> --- 
> You received this message because you are subscribed to the Google Groups 
> "sqlalchemy" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to sqlalchemy+...@googlegroups.com.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/sqlalchemy/07c76e07-17d4-4cea-9e42-1965ad80a06fn%40googlegroups.com
>  
> 

Re: [sqlalchemy] Turn off connections invalidation functionality

[Mike Bayer]

On Mon, Jan 10, 2022, at 1:30 PM, Anupama Goparaju wrote:
> Thanks. Looks like this works but we need to set it for every exception 
> scenario. Just confirming if the exception_context is thread safe to set the 
> attribute.

yes this all happens local to the execute() function call, is not exposed to 
threads


> Also, does this setting prevent pool invalidation on all sort of exceptions 
> related to connections?

yes, the pathway by which getting an exception would lead to invalidating the 
connection is blocked by this event handler.   I'm not sure why you'd want to 
set that in all cases as there are legitimate "disconnect" error scenarios 
(such as database was stopped and restarted), unless you are doing something 
with the DBAPI connection that allows it to recover by itself, I guess.

> 
> @event.listens_for(Engine, *'handle_error'*)
> def receive_handle_error(exception_context):
>  if exception_context.invalidate_pool_on_disconnect:
>  exception_context.invalidate_pool_on_disconnect = False
> 
> On Thursday, January 6, 2022 at 10:03:55 AM UTC-8 Anupama Goparaju wrote:
>> Thanks, i will give it a try.
>> 
>> On Thursday, January 6, 2022 at 5:23:09 AM UTC-8 Mike Bayer wrote:
>>> __
>>> I can't guarantee that overriding private methods is safe, no.
>>> 
>>> there's a public API to disable errors resulting in invalidation, I suggest 
>>> you use that.
>>> 
>>> 
>>> 
>>> On Wed, Jan 5, 2022, at 7:35 PM, Anupama Goparaju wrote:
 I haven't read the response before and tried to skip the lib logic by 
 overriding the function below in my child call extending the NullPool to 
 do nothing. Is this safe to do?
 
 def _invalidate(self, connection, exception=None, _checkin=True):
   pass
 
 On Wednesday, January 5, 2022 at 4:33:01 PM UTC-8 Anupama Goparaju wrote:
> Great, thanks for the info.
> 
> On Friday, November 26, 2021 at 9:30:02 AM UTC-8 Mike Bayer wrote:
>> __
>> I've spent some time thinking about what might be being asked here.
>> the only thing I can think of is that when a particular database 
>> connection is found to be in what we call a "disconnect" state, the 
>> connection is invalidated, so that the connection will reconnect and 
>> make a new connection.   But also, this operation will typically assume 
>> the "disconnect" condition is that the database was restarted, or some 
>> other network condition has probably made all the connections that are 
>> pooled also invalid.   So the entire pool will be invalidated in this 
>> case as well.
>> 
>> Why someone might want to turn that off is if they are getting lots of 
>> invalidated connections for some other reason and they are not able to 
>> solve that problem, so they'd like the pool to not be invalidated 
>> totally.  This means that if the database is restarted, and for example 
>> you have 20 pooled connections, you will in a high-request environment 
>> get up to 20 server errors unless pool_pre_ping is turned on so that the 
>> connections are refreshed one at at time.
>> 
>> To disable the pool invalidation upon receipt of a single connection 
>> shown to be in a disconnect, implement the handle_error event: 
>> https://docs.sqlalchemy.org/en/14/core/events.html#sqlalchemy.events.ConnectionEvents.handle_error
>>  and then set invalidate_pool_on_disconnect to False: 
>> https://docs.sqlalchemy.org/en/14/core/connections.html?highlight=invalidate_pool_on_disconnect#sqlalchemy.engine.ExceptionContext.invalidate_pool_on_disconnect
>>  .
>> 
>> 
>> 
>> On Fri, Nov 26, 2021, at 11:51 AM, Mike Bayer wrote:
>>> Im not sure if I understand the question?   if you don't call 
>>> .invalidate(), then the connection is not invalidated.
>>> 
>>> what does "turn off" mean ?
>>> 
>>> 
>>> 
>>> On Fri, Nov 26, 2021, at 11:17 AM, Anupama Goparaju wrote:
 Hi,
 
 Is there a way to safely turn off connection invalidation 
 functionality (based on invalidation time set, all the connections 
 created prior to the timestamp are invalidated) in sqlalchemy?
 
 https://github.com/Noethys/Connecthys/blob/master/connecthys/lib/sqlalchemy/pool.py#L574
 
 Thanks,
 Anupama
 
 
 -- 
 SQLAlchemy - 
 The Python SQL Toolkit and Object Relational Mapper
  
 http://www.sqlalchemy.org/
  
 To post example code, please provide an MCVE: Minimal, Complete, and 
 Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
 description.
 --- 
 You received this message because you are subscribed to the Google 
 Groups "sqlalchemy" group.
 To unsubscribe from this group and stop receiving emails from it, send 
 an email to 

Re: [sqlalchemy] Turn off connections invalidation functionality

[Anupama Goparaju]

Thanks. Looks like this works but we need to set it for every exception 
scenario. Just confirming if the exception_context is thread safe to set 
the attribute.
Also, does this setting prevent pool invalidation on all sort of exceptions 
related to connections?

@event.listens_for(Engine, 'handle_error')
def receive_handle_error(exception_context):
 if exception_context.invalidate_pool_on_disconnect:
 exception_context.invalidate_pool_on_disconnect = False


On Thursday, January 6, 2022 at 10:03:55 AM UTC-8 Anupama Goparaju wrote:

> Thanks, i will give it a try.
>
> On Thursday, January 6, 2022 at 5:23:09 AM UTC-8 Mike Bayer wrote:
>
>> I can't guarantee that overriding private methods is safe, no.
>>
>> there's a public API to disable errors resulting in invalidation, I 
>> suggest you use that.
>>
>>
>>
>> On Wed, Jan 5, 2022, at 7:35 PM, Anupama Goparaju wrote:
>>
>> I haven't read the response before and tried to skip the lib logic by 
>> overriding the function below in my child call extending the NullPool to do 
>> nothing. Is this safe to do?
>>
>> def _invalidate(self, connection, exception=None, _checkin=True):
>>   pass
>>
>> On Wednesday, January 5, 2022 at 4:33:01 PM UTC-8 Anupama Goparaju wrote:
>>
>> Great, thanks for the info.
>>
>> On Friday, November 26, 2021 at 9:30:02 AM UTC-8 Mike Bayer wrote:
>>
>>
>> I've spent some time thinking about what might be being asked here.
>> the only thing I can think of is that when a particular database connection 
>> is found to be in what we call a "disconnect" state, the connection is 
>> invalidated, so that the connection will reconnect and make a new 
>> connection.   But also, this operation will typically assume the 
>> "disconnect" condition is that the database was restarted, or some other 
>> network condition has probably made all the connections that are pooled 
>> also invalid.   So the entire pool will be invalidated in this case as well.
>>
>> Why someone might want to turn that off is if they are getting lots of 
>> invalidated connections for some other reason and they are not able to 
>> solve that problem, so they'd like the pool to not be invalidated totally.  
>> This means that if the database is restarted, and for example you have 20 
>> pooled connections, you will in a high-request environment get up to 20 
>> server errors unless pool_pre_ping is turned on so that the connections are 
>> refreshed one at at time.
>>
>> To disable the pool invalidation upon receipt of a single connection 
>> shown to be in a disconnect, implement the handle_error event: 
>> https://docs.sqlalchemy.org/en/14/core/events.html#sqlalchemy.events.ConnectionEvents.handle_error
>>  
>> and then set invalidate_pool_on_disconnect to False: 
>> https://docs.sqlalchemy.org/en/14/core/connections.html?highlight=invalidate_pool_on_disconnect#sqlalchemy.engine.ExceptionContext.invalidate_pool_on_disconnect
>>  
>> .
>>
>>
>>
>> On Fri, Nov 26, 2021, at 11:51 AM, Mike Bayer wrote:
>>
>> Im not sure if I understand the question?   if you don't call 
>> .invalidate(), then the connection is not invalidated.
>>
>> what does "turn off" mean ?
>>
>>
>>
>> On Fri, Nov 26, 2021, at 11:17 AM, Anupama Goparaju wrote:
>>
>> Hi,
>>
>> Is there a way to safely turn off connection invalidation functionality 
>> (based on invalidation time set, all the connections created prior to the 
>> timestamp are invalidated) in sqlalchemy?
>>
>>
>> https://github.com/Noethys/Connecthys/blob/master/connecthys/lib/sqlalchemy/pool.py#L574
>>
>> Thanks,
>> Anupama
>>
>>
>> -- 
>> SQLAlchemy - 
>> The Python SQL Toolkit and Object Relational Mapper
>>  
>> http://www.sqlalchemy.org/
>>  
>> To post example code, please provide an MCVE: Minimal, Complete, and 
>> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
>> description.
>> --- 
>> You received this message because you are subscribed to the Google Groups 
>> "sqlalchemy" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to sqlalchemy+...@googlegroups.com.
>> To view this discussion on the web visit 
>> https://groups.google.com/d/msgid/sqlalchemy/07c76e07-17d4-4cea-9e42-1965ad80a06fn%40googlegroups.com
>>  
>> 
>> .
>>
>>
>>
>> -- 
>> SQLAlchemy - 
>> The Python SQL Toolkit and Object Relational Mapper
>>  
>> http://www.sqlalchemy.org/
>>  
>> To post example code, please provide an MCVE: Minimal, Complete, and 
>> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
>> description.
>> --- 
>> You received this message because you are subscribed to the Google Groups 
>> "sqlalchemy" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to sqlalchemy+...@googlegroups.com.
>>
>> To view this discussion on the web visit 
>> 

Re: [sqlalchemy] Turn off connections invalidation functionality

[Anupama Goparaju]

Thanks, i will give it a try.

On Thursday, January 6, 2022 at 5:23:09 AM UTC-8 Mike Bayer wrote:

> I can't guarantee that overriding private methods is safe, no.
>
> there's a public API to disable errors resulting in invalidation, I 
> suggest you use that.
>
>
>
> On Wed, Jan 5, 2022, at 7:35 PM, Anupama Goparaju wrote:
>
> I haven't read the response before and tried to skip the lib logic by 
> overriding the function below in my child call extending the NullPool to do 
> nothing. Is this safe to do?
>
> def _invalidate(self, connection, exception=None, _checkin=True):
>   pass
>
> On Wednesday, January 5, 2022 at 4:33:01 PM UTC-8 Anupama Goparaju wrote:
>
> Great, thanks for the info.
>
> On Friday, November 26, 2021 at 9:30:02 AM UTC-8 Mike Bayer wrote:
>
>
> I've spent some time thinking about what might be being asked here.the 
> only thing I can think of is that when a particular database connection is 
> found to be in what we call a "disconnect" state, the connection is 
> invalidated, so that the connection will reconnect and make a new 
> connection.   But also, this operation will typically assume the 
> "disconnect" condition is that the database was restarted, or some other 
> network condition has probably made all the connections that are pooled 
> also invalid.   So the entire pool will be invalidated in this case as well.
>
> Why someone might want to turn that off is if they are getting lots of 
> invalidated connections for some other reason and they are not able to 
> solve that problem, so they'd like the pool to not be invalidated totally.  
> This means that if the database is restarted, and for example you have 20 
> pooled connections, you will in a high-request environment get up to 20 
> server errors unless pool_pre_ping is turned on so that the connections are 
> refreshed one at at time.
>
> To disable the pool invalidation upon receipt of a single connection shown 
> to be in a disconnect, implement the handle_error event: 
> https://docs.sqlalchemy.org/en/14/core/events.html#sqlalchemy.events.ConnectionEvents.handle_error
>  
> and then set invalidate_pool_on_disconnect to False: 
> https://docs.sqlalchemy.org/en/14/core/connections.html?highlight=invalidate_pool_on_disconnect#sqlalchemy.engine.ExceptionContext.invalidate_pool_on_disconnect
>  
> .
>
>
>
> On Fri, Nov 26, 2021, at 11:51 AM, Mike Bayer wrote:
>
> Im not sure if I understand the question?   if you don't call 
> .invalidate(), then the connection is not invalidated.
>
> what does "turn off" mean ?
>
>
>
> On Fri, Nov 26, 2021, at 11:17 AM, Anupama Goparaju wrote:
>
> Hi,
>
> Is there a way to safely turn off connection invalidation functionality 
> (based on invalidation time set, all the connections created prior to the 
> timestamp are invalidated) in sqlalchemy?
>
>
> https://github.com/Noethys/Connecthys/blob/master/connecthys/lib/sqlalchemy/pool.py#L574
>
> Thanks,
> Anupama
>
>
> -- 
> SQLAlchemy - 
> The Python SQL Toolkit and Object Relational Mapper
>  
> http://www.sqlalchemy.org/
>  
> To post example code, please provide an MCVE: Minimal, Complete, and 
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
> description.
> --- 
> You received this message because you are subscribed to the Google Groups 
> "sqlalchemy" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to sqlalchemy+...@googlegroups.com.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/sqlalchemy/07c76e07-17d4-4cea-9e42-1965ad80a06fn%40googlegroups.com
>  
> 
> .
>
>
>
> -- 
> SQLAlchemy - 
> The Python SQL Toolkit and Object Relational Mapper
>  
> http://www.sqlalchemy.org/
>  
> To post example code, please provide an MCVE: Minimal, Complete, and 
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
> description.
> --- 
> You received this message because you are subscribed to the Google Groups 
> "sqlalchemy" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to sqlalchemy+...@googlegroups.com.
>
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/sqlalchemy/a1807f9d-e0c4-4ee6-9c03-ff2a56afeded%40www.fastmail.com
>  
> 
> .
>
>
>
> -- 
> SQLAlchemy - 
> The Python SQL Toolkit and Object Relational Mapper
>  
> http://www.sqlalchemy.org/
>  
> To post example code, please provide an MCVE: Minimal, Complete, and 
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
> description.
> --- 
> You received this message because you are subscribed to the Google Groups 
> "sqlalchemy" group.
> To unsubscribe from this group and stop receiving emails from it, send an 

Re: [sqlalchemy] Turn off connections invalidation functionality

[Mike Bayer]

I can't guarantee that overriding private methods is safe, no.

there's a public API to disable errors resulting in invalidation, I suggest you 
use that.



On Wed, Jan 5, 2022, at 7:35 PM, Anupama Goparaju wrote:
> I haven't read the response before and tried to skip the lib logic by 
> overriding the function below in my child call extending the NullPool to do 
> nothing. Is this safe to do?
> 
> def _invalidate(self, connection, exception=None, _checkin=True):
>   pass
> 
> On Wednesday, January 5, 2022 at 4:33:01 PM UTC-8 Anupama Goparaju wrote:
>> Great, thanks for the info.
>> 
>> On Friday, November 26, 2021 at 9:30:02 AM UTC-8 Mike Bayer wrote:
>>> __
>>> I've spent some time thinking about what might be being asked here.the 
>>> only thing I can think of is that when a particular database connection is 
>>> found to be in what we call a "disconnect" state, the connection is 
>>> invalidated, so that the connection will reconnect and make a new 
>>> connection.   But also, this operation will typically assume the 
>>> "disconnect" condition is that the database was restarted, or some other 
>>> network condition has probably made all the connections that are pooled 
>>> also invalid.   So the entire pool will be invalidated in this case as well.
>>> 
>>> Why someone might want to turn that off is if they are getting lots of 
>>> invalidated connections for some other reason and they are not able to 
>>> solve that problem, so they'd like the pool to not be invalidated totally.  
>>> This means that if the database is restarted, and for example you have 20 
>>> pooled connections, you will in a high-request environment get up to 20 
>>> server errors unless pool_pre_ping is turned on so that the connections are 
>>> refreshed one at at time.
>>> 
>>> To disable the pool invalidation upon receipt of a single connection shown 
>>> to be in a disconnect, implement the handle_error event: 
>>> https://docs.sqlalchemy.org/en/14/core/events.html#sqlalchemy.events.ConnectionEvents.handle_error
>>>  and then set invalidate_pool_on_disconnect to False: 
>>> https://docs.sqlalchemy.org/en/14/core/connections.html?highlight=invalidate_pool_on_disconnect#sqlalchemy.engine.ExceptionContext.invalidate_pool_on_disconnect
>>>  .
>>> 
>>> 
>>> 
>>> On Fri, Nov 26, 2021, at 11:51 AM, Mike Bayer wrote:
 Im not sure if I understand the question?   if you don't call 
 .invalidate(), then the connection is not invalidated.
 
 what does "turn off" mean ?
 
 
 
 On Fri, Nov 26, 2021, at 11:17 AM, Anupama Goparaju wrote:
> Hi,
> 
> Is there a way to safely turn off connection invalidation functionality 
> (based on invalidation time set, all the connections created prior to the 
> timestamp are invalidated) in sqlalchemy?
> 
> https://github.com/Noethys/Connecthys/blob/master/connecthys/lib/sqlalchemy/pool.py#L574
> 
> Thanks,
> Anupama
> 
> 
> -- 
> SQLAlchemy - 
> The Python SQL Toolkit and Object Relational Mapper
>  
> http://www.sqlalchemy.org/
>  
> To post example code, please provide an MCVE: Minimal, Complete, and 
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
> description.
> --- 
> You received this message because you are subscribed to the Google Groups 
> "sqlalchemy" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to sqlalchemy+...@googlegroups.com.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/sqlalchemy/07c76e07-17d4-4cea-9e42-1965ad80a06fn%40googlegroups.com
>  
> .
 
 
 
 -- 
 SQLAlchemy - 
 The Python SQL Toolkit and Object Relational Mapper
  
 http://www.sqlalchemy.org/
  
 To post example code, please provide an MCVE: Minimal, Complete, and 
 Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
 description.
 --- 
 You received this message because you are subscribed to the Google Groups 
 "sqlalchemy" group.
 To unsubscribe from this group and stop receiving emails from it, send an 
 email to sqlalchemy+...@googlegroups.com.
 To view this discussion on the web visit 
 https://groups.google.com/d/msgid/sqlalchemy/a1807f9d-e0c4-4ee6-9c03-ff2a56afeded%40www.fastmail.com
  
 .
>>> 
> 
> 
> -- 
> SQLAlchemy - 
> The Python SQL Toolkit and Object Relational Mapper
>  
> http://www.sqlalchemy.org/
>  
> To post example code, please provide an MCVE: Minimal, Complete, and 
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
> description.
> --- 
> You received this 

Re: [sqlalchemy] Turn off connections invalidation functionality

[Anupama Goparaju]

I haven't read the response before and tried to skip the lib logic by 
overriding the function below in my child call extending the NullPool to do 
nothing. Is this safe to do?

def _invalidate(self, connection, exception=None, _checkin=True):
  pass


On Wednesday, January 5, 2022 at 4:33:01 PM UTC-8 Anupama Goparaju wrote:

> Great, thanks for the info.
>
> On Friday, November 26, 2021 at 9:30:02 AM UTC-8 Mike Bayer wrote:
>
>> I've spent some time thinking about what might be being asked here.
>> the only thing I can think of is that when a particular database connection 
>> is found to be in what we call a "disconnect" state, the connection is 
>> invalidated, so that the connection will reconnect and make a new 
>> connection.   But also, this operation will typically assume the 
>> "disconnect" condition is that the database was restarted, or some other 
>> network condition has probably made all the connections that are pooled 
>> also invalid.   So the entire pool will be invalidated in this case as well.
>>
>> Why someone might want to turn that off is if they are getting lots of 
>> invalidated connections for some other reason and they are not able to 
>> solve that problem, so they'd like the pool to not be invalidated totally.  
>> This means that if the database is restarted, and for example you have 20 
>> pooled connections, you will in a high-request environment get up to 20 
>> server errors unless pool_pre_ping is turned on so that the connections are 
>> refreshed one at at time.
>>
>> To disable the pool invalidation upon receipt of a single connection 
>> shown to be in a disconnect, implement the handle_error event: 
>> https://docs.sqlalchemy.org/en/14/core/events.html#sqlalchemy.events.ConnectionEvents.handle_error
>>  
>> and then set invalidate_pool_on_disconnect to False: 
>> https://docs.sqlalchemy.org/en/14/core/connections.html?highlight=invalidate_pool_on_disconnect#sqlalchemy.engine.ExceptionContext.invalidate_pool_on_disconnect
>>  
>> .
>>
>>
>>
>> On Fri, Nov 26, 2021, at 11:51 AM, Mike Bayer wrote:
>>
>> Im not sure if I understand the question?   if you don't call 
>> .invalidate(), then the connection is not invalidated.
>>
>> what does "turn off" mean ?
>>
>>
>>
>> On Fri, Nov 26, 2021, at 11:17 AM, Anupama Goparaju wrote:
>>
>> Hi,
>>
>> Is there a way to safely turn off connection invalidation functionality 
>> (based on invalidation time set, all the connections created prior to the 
>> timestamp are invalidated) in sqlalchemy?
>>
>>
>> https://github.com/Noethys/Connecthys/blob/master/connecthys/lib/sqlalchemy/pool.py#L574
>>
>> Thanks,
>> Anupama
>>
>>
>> -- 
>> SQLAlchemy - 
>> The Python SQL Toolkit and Object Relational Mapper
>>  
>> http://www.sqlalchemy.org/
>>  
>> To post example code, please provide an MCVE: Minimal, Complete, and 
>> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
>> description.
>> --- 
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>>  
>> 
>> .
>>
>>
>>
>> -- 
>> SQLAlchemy - 
>> The Python SQL Toolkit and Object Relational Mapper
>>  
>> http://www.sqlalchemy.org/
>>  
>> To post example code, please provide an MCVE: Minimal, Complete, and 
>> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
>> description.
>> --- 
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>>  
>> 
>> .
>>
>>
>>

-- 
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http://www.sqlalchemy.org/

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Re: [sqlalchemy] Turn off connections invalidation functionality

[Anupama Goparaju]

Great, thanks for the info.

On Friday, November 26, 2021 at 9:30:02 AM UTC-8 Mike Bayer wrote:

> I've spent some time thinking about what might be being asked here.the 
> only thing I can think of is that when a particular database connection is 
> found to be in what we call a "disconnect" state, the connection is 
> invalidated, so that the connection will reconnect and make a new 
> connection.   But also, this operation will typically assume the 
> "disconnect" condition is that the database was restarted, or some other 
> network condition has probably made all the connections that are pooled 
> also invalid.   So the entire pool will be invalidated in this case as well.
>
> Why someone might want to turn that off is if they are getting lots of 
> invalidated connections for some other reason and they are not able to 
> solve that problem, so they'd like the pool to not be invalidated totally.  
> This means that if the database is restarted, and for example you have 20 
> pooled connections, you will in a high-request environment get up to 20 
> server errors unless pool_pre_ping is turned on so that the connections are 
> refreshed one at at time.
>
> To disable the pool invalidation upon receipt of a single connection shown 
> to be in a disconnect, implement the handle_error event: 
> https://docs.sqlalchemy.org/en/14/core/events.html#sqlalchemy.events.ConnectionEvents.handle_error
>  
> and then set invalidate_pool_on_disconnect to False: 
> https://docs.sqlalchemy.org/en/14/core/connections.html?highlight=invalidate_pool_on_disconnect#sqlalchemy.engine.ExceptionContext.invalidate_pool_on_disconnect
>  
> .
>
>
>
> On Fri, Nov 26, 2021, at 11:51 AM, Mike Bayer wrote:
>
> Im not sure if I understand the question?   if you don't call 
> .invalidate(), then the connection is not invalidated.
>
> what does "turn off" mean ?
>
>
>
> On Fri, Nov 26, 2021, at 11:17 AM, Anupama Goparaju wrote:
>
> Hi,
>
> Is there a way to safely turn off connection invalidation functionality 
> (based on invalidation time set, all the connections created prior to the 
> timestamp are invalidated) in sqlalchemy?
>
>
> https://github.com/Noethys/Connecthys/blob/master/connecthys/lib/sqlalchemy/pool.py#L574
>
> Thanks,
> Anupama
>
>
> -- 
> SQLAlchemy - 
> The Python SQL Toolkit and Object Relational Mapper
>  
> http://www.sqlalchemy.org/
>  
> To post example code, please provide an MCVE: Minimal, Complete, and 
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
> description.
> --- 
> You received this message because you are subscribed to the Google Groups 
> "sqlalchemy" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to sqlalchemy+...@googlegroups.com.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/sqlalchemy/07c76e07-17d4-4cea-9e42-1965ad80a06fn%40googlegroups.com
>  
> 
> .
>
>
>
> -- 
> SQLAlchemy - 
> The Python SQL Toolkit and Object Relational Mapper
>  
> http://www.sqlalchemy.org/
>  
> To post example code, please provide an MCVE: Minimal, Complete, and 
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
> description.
> --- 
> You received this message because you are subscribed to the Google Groups 
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>
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/sqlalchemy/a1807f9d-e0c4-4ee6-9c03-ff2a56afeded%40www.fastmail.com
>  
> 
> .
>
>
>

-- 
SQLAlchemy - 
The Python SQL Toolkit and Object Relational Mapper

http://www.sqlalchemy.org/

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Example.  See  http://stackoverflow.com/help/mcve for a full description.
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Re: [sqlalchemy] Turn off connections invalidation functionality

[Mike Bayer]

I've spent some time thinking about what might be being asked here.the only 
thing I can think of is that when a particular database connection is found to 
be in what we call a "disconnect" state, the connection is invalidated, so that 
the connection will reconnect and make a new connection.   But also, this 
operation will typically assume the "disconnect" condition is that the database 
was restarted, or some other network condition has probably made all the 
connections that are pooled also invalid.   So the entire pool will be 
invalidated in this case as well.

Why someone might want to turn that off is if they are getting lots of 
invalidated connections for some other reason and they are not able to solve 
that problem, so they'd like the pool to not be invalidated totally.  This 
means that if the database is restarted, and for example you have 20 pooled 
connections, you will in a high-request environment get up to 20 server errors 
unless pool_pre_ping is turned on so that the connections are refreshed one at 
at time.

To disable the pool invalidation upon receipt of a single connection shown to 
be in a disconnect, implement the handle_error event: 
https://docs.sqlalchemy.org/en/14/core/events.html#sqlalchemy.events.ConnectionEvents.handle_error
 and then set invalidate_pool_on_disconnect to False: 
https://docs.sqlalchemy.org/en/14/core/connections.html?highlight=invalidate_pool_on_disconnect#sqlalchemy.engine.ExceptionContext.invalidate_pool_on_disconnect
 .



On Fri, Nov 26, 2021, at 11:51 AM, Mike Bayer wrote:
> Im not sure if I understand the question?   if you don't call .invalidate(), 
> then the connection is not invalidated.
> 
> what does "turn off" mean ?
> 
> 
> 
> On Fri, Nov 26, 2021, at 11:17 AM, Anupama Goparaju wrote:
>> Hi,
>> 
>> Is there a way to safely turn off connection invalidation functionality 
>> (based on invalidation time set, all the connections created prior to the 
>> timestamp are invalidated) in sqlalchemy?
>> 
>> https://github.com/Noethys/Connecthys/blob/master/connecthys/lib/sqlalchemy/pool.py#L574
>> 
>> Thanks,
>> Anupama
>> 
>> 
>> -- 
>> SQLAlchemy - 
>> The Python SQL Toolkit and Object Relational Mapper
>>  
>> http://www.sqlalchemy.org/
>>  
>> To post example code, please provide an MCVE: Minimal, Complete, and 
>> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
>> description.
>> --- 
>> You received this message because you are subscribed to the Google Groups 
>> "sqlalchemy" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to sqlalchemy+unsubscr...@googlegroups.com.
>> To view this discussion on the web visit 
>> https://groups.google.com/d/msgid/sqlalchemy/07c76e07-17d4-4cea-9e42-1965ad80a06fn%40googlegroups.com
>>  
>> .
> 
> 
> 
> -- 
> SQLAlchemy - 
> The Python SQL Toolkit and Object Relational Mapper
>  
> http://www.sqlalchemy.org/
>  
> To post example code, please provide an MCVE: Minimal, Complete, and 
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
> description.
> --- 
> You received this message because you are subscribed to the Google Groups 
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>  
> .

-- 
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The Python SQL Toolkit and Object Relational Mapper

http://www.sqlalchemy.org/

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Example.  See  http://stackoverflow.com/help/mcve for a full description.
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Re: [sqlalchemy] Turn off connections invalidation functionality

[Mike Bayer]

Im not sure if I understand the question?   if you don't call .invalidate(), 
then the connection is not invalidated.

what does "turn off" mean ?



On Fri, Nov 26, 2021, at 11:17 AM, Anupama Goparaju wrote:
> Hi,
> 
> Is there a way to safely turn off connection invalidation functionality 
> (based on invalidation time set, all the connections created prior to the 
> timestamp are invalidated) in sqlalchemy?
> 
> https://github.com/Noethys/Connecthys/blob/master/connecthys/lib/sqlalchemy/pool.py#L574
> 
> Thanks,
> Anupama
> 
> 
> -- 
> SQLAlchemy - 
> The Python SQL Toolkit and Object Relational Mapper
>  
> http://www.sqlalchemy.org/
>  
> To post example code, please provide an MCVE: Minimal, Complete, and 
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full 
> description.
> --- 
> You received this message because you are subscribed to the Google Groups 
> "sqlalchemy" group.
> To unsubscribe from this group and stop receiving emails from it, send an 
> email to sqlalchemy+unsubscr...@googlegroups.com.
> To view this discussion on the web visit 
> https://groups.google.com/d/msgid/sqlalchemy/07c76e07-17d4-4cea-9e42-1965ad80a06fn%40googlegroups.com
>  
> .

-- 
SQLAlchemy - 
The Python SQL Toolkit and Object Relational Mapper

http://www.sqlalchemy.org/

To post example code, please provide an MCVE: Minimal, Complete, and Verifiable 
Example.  See  http://stackoverflow.com/help/mcve for a full description.
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