Re: What would AggrefExprState nodes' args contain?

I have a small db which I am using to test it. Moreover I am new to the
terms. What would you mean by 'regression'?

Also, I am using eclipse for browsing the code. It resolves all references
and function calls, declarations, definitions etc.

Regards,
Vaibhav

On Fri, Apr 29, 2011 at 3:31 PM, Ashutosh Bapat <
ashutosh(dot)bapat(at)enterprisedb(dot)com> wrote:

> Is regression clean?
>
> Have you looked at how the member is used using some code browsing tool
> like cscope by examining it's every occurrence? PG uses simulated run time
> polymorphism a lot, so any Node should examined carefully from that angle
> too. Even after all of that if you think that it's not being used, you can
> submit a patch to community removing that member. Somebody from community
> reviewers will review and commit the patch if they find it correct and
> useful.
>
> Read http://wiki.postgresql.org/wiki/Submitting_a_Patch before submitting
> the patch.
>
>
> On Fri, Apr 29, 2011 at 3:22 PM, Vaibhav Kaushal <
> vaibhavkaushal123(at)gmail(dot)com> wrote:
>
>> I tried all aggregates - min,max,sum,count and avg. all are working. What
>> do you suggest now?
>>
>>
>> On Fri, Apr 29, 2011 at 11:30 AM, Ashutosh Bapat <
>> ashutosh(dot)bapat(at)enterprisedb(dot)com> wrote:
>>
>>>
>>>
>>> On Thu, Apr 28, 2011 at 4:21 PM, Vaibhav Kaushal <
>>> vaibhavkaushal123(at)gmail(dot)com> wrote:
>>>
>>>> Thanks a lot. I was browsing the code and was thinking this would be the
>>>> most probable scenario.
>>>>
>>>> But, the point is that even after removing the args initialization part
>>>> in the ExecInitExpr for AggrefState, the sum() function is working. I
>>>> believe that is also a aggregate function! If yes, then how is it working if
>>>> I dd not allow the args to be initialized. The debugger says that
>>>> ExecEvalAggref was called and the results returned are true.
>>>>
>>>>
>>> Did you check the same thing with avg, or any statistical aggregates. Sum
>>> does not need all the aggregate infrastructure in place, for example
>>> finalisation function. May be after removing initialization part you want to
>>> run regression (or at least aggregates.sql) to see what it breaks.
>>>
>>>
>>>> Regards,
>>>> Vaibhav
>>>>
>>>>
>>>> On Thu, Apr 28, 2011 at 2:38 PM, Ashutosh Bapat <
>>>> ashutosh(dot)bapat(at)enterprisedb(dot)com> wrote:
>>>>
>>>>> The args in AggrefExprState, are used in the functions ExecAgg,
>>>>> ExecInitAgg and their minions to evaluate the aggregates. The
>>>>> ExecEvalAggref() merely retrieves the results of aggregation calculated
>>>>> during ExecAgg.
>>>>>
>>>>>
>>>>> On Tue, Apr 26, 2011 at 12:04 PM, Vaibhav Kaushal <
>>>>> vaibhavkaushal123(at)gmail(dot)com> wrote:
>>>>>
>>>>>> Hello all,
>>>>>>
>>>>>> While examining the executor, I was wondering what the *args part of
>>>>>> AggrefExprState nodes contain. I found that the Aggref (Expr)'s args list
>>>>>> is a list of TargetEntry nodes. But the state node's args is initialized in
>>>>>> ExecInitExpr as:
>>>>>>
>>>>>> astate->args = (List *) ExecInitExpr((Expr *) aggref->args,
>>>>>> parent);
>>>>>>
>>>>>> This would mean that the args is actually a ExprState node list with
>>>>>> one single item (the ExprState node / tree). I believe it potentially
>>>>>> contains the execution tree to determine the state / value of the aggref
>>>>>> (sub)expression. But then in the ExecEvalAggref function I do not see the
>>>>>> args coming into picture at all! I am also unable to find a call to some
>>>>>> function for executing the state node created in the args list. Also, no
>>>>>> value is being extracted from that node! Why is it so?
>>>>>>
>>>>>> For quick reference I am adding the function (may be you don't need it
>>>>>> but still... its a small one):
>>>>>>
>>>>>> /* ----------------------------------------------------------------
>>>>>> * ExecEvalAggref
>>>>>> *
>>>>>> * Returns a Datum whose value is the value of the precomputed
>>>>>> * aggregate found in the given expression context.
>>>>>> * ----------------------------------------------------------------
>>>>>> */
>>>>>> static Datum
>>>>>> ExecEvalAggref(AggrefExprState *aggref, ExprContext *econtext,
>>>>>> bool *isNull, ExprDoneCond *isDone)
>>>>>> {
>>>>>> if (isDone)
>>>>>> *isDone = ExprSingleResult;
>>>>>>
>>>>>> if (econtext->ecxt_aggvalues == NULL) /* safety check */
>>>>>> elog(ERROR, "no aggregates in this expression context");
>>>>>>
>>>>>> *isNull = econtext->ecxt_aggnulls[aggref->aggno];
>>>>>> return econtext->ecxt_aggvalues[aggref->aggno];
>>>>>> }
>>>>>>
>>>>>>
>>>>>> What is the use of args in AggrefExprState node here? Is it there just
>>>>>> for some historical reason?
>>>>>>
>>>>>> Regards,
>>>>>> Vaibhav
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Best Wishes,
>>>>> Ashutosh Bapat
>>>>> EntepriseDB Corporation
>>>>> The Enterprise Postgres Company
>>>>>
>>>>>
>>>>
>>>
>>>
>>> --
>>> Best Wishes,
>>> Ashutosh Bapat
>>> EntepriseDB Corporation
>>> The Enterprise Postgres Company
>>>
>>>
>>
>
>
> --
> Best Wishes,
> Ashutosh Bapat
> EntepriseDB Corporation
> The Enterprise Postgres Company
>
>