Re: Patch: show relation and tuple infos of a lock to acquire

On 31 December 2013 16:36, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Simon Riggs <simon(at)2ndQuadrant(dot)com> writes:
>> On 31 December 2013 09:12, Christian Kruse <christian(at)2ndquadrant(dot)com> wrote:
>>> Output with patch:
>>>
>>> LOG: process 24774 acquired ShareLock on transaction 696 after 11688.720 ms
>>> CONTEXT: relation name: foo (OID 16385)
>>> tuple (ctid (0,1)): (1)
>
>> That is useful info.
>
>> I think the message should be changed to say this only, without a context line
>
>> LOG: process 24774 acquired ShareLock on relation "foo" (OID 16385)
>> tuple (0,1) after 11688.720 ms
>
>> My reason is that pid 24774 was waiting for a *tuple lock* and it was
>> eventually granted, so thats what it should say.
>
> No, that wasn't what it was waiting for, and lying to the user like that
> isn't going to make things better.

"Like that" is ambiguous and I don't understand you or what you are
objecting to.

When we run SELECT ... FOR SHARE we are attempting to lock rows. Why
is the transaction we are waiting for important when we wait to lock
rows, but when we wait to lock relations it isn't?

--
Simon Riggs http://www.2ndQuadrant.com/
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