Re: Request: pg_cancel_backend variant that handles 'idle in transaction' sessions

On 11/05/2015 10:09 AM, Pavel Stehule wrote:
> On 5.11.2015 19:02 Merlin Moncure wrote:
>> Thus, I think we have consensus that transaction_timeout is good -- it
>> would deprecate statement_timeout essentially.  Likewise,
>> pg_cancel_transaction is good and would deprecate pg_cancel_backend;
>> it's hard for me to imagine a scenario where a user would call
>> pg_cancel_backend if pg_cancel_transaction were to be available.
>
> I am sorry, I see a consensus between you and Stephen only.

S
t                    C
a<-------------<transaction>--------------->E
r    A      B     A      B      A           n
t <idle> <stmt> <idle> <stmt> <idle>        d
|--------======--------======---------------|

Currently we can set timeout and cancel for period B (<stmt>). I can see
based on this discussion that there are legitimate use cases for wanting
timeout and cancel for any of the periods A, B, or C.

I guess the question then becomes how we provide that coverage. I think
for coverage of timeout you need three individual timeout settings.
However for cancel, it would seem that pg_cancel_transaction would cover
all three cases.

Joe

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