Re: How to copy Datum

Hi,

I'm trying to reduce the re-computing of window aggregation. Here the
AVG function for example.

The original window aggregation's transition value(transValue) of AVG is
an ArrayType, that contains two main values(sum, count).

Now, I'm using a temporary transition value (tempTransValue), and I need
to copy tempTransValue to the original window aggregation's transition
value(transValue).

I used the function datumCopy as following:

peraggstate->transValue = datumCopy(peraggstate->tempTransValue,
peraggstate->transtypeByVal, peraggstate->transtypeLen);

But when the copied transValue is passed to the invoke function, here is
int4_avg_accum, the ArrayType returned from PG_GETARG_ARRAYTYPE_P(0) is
null.

Which means the copy action is failed.

Anybody know why? Or give me some suggestions? Thanks very much.

Best Regards

Chaoyong Wang

2012/8/21 Wang, Chaoyong <Chaoyong(dot)Wang(at)emc(dot)com>:

[..]

> But when the copied transValue is passed to the invoke function, here is
> int4_avg_accum, the ArrayType returned from PG_GETARG_ARRAYTYPE_P(0) is
> null.
>
> Which means the copy action is failed.
>
> Anybody know why? Or give me some suggestions? Thanks very much.

I suggest you ask this question on -hackers instead of here on
-cluster-hackers, as it doesn’t seem to have anything to do with
clustering.

Nicolas

--
A. Because it breaks the logical sequence of discussion.
Q. Why is top posting bad?

Sorry, it's my mistake, I was intended to send to -hackers, but I clicked the wrong email.
Anyway, I have solved the problem, thanks.

-----Original Message-----
From: Nicolas Barbier [mailto:nicolas(dot)barbier(at)gmail(dot)com]
Sent: 2012年8月22日 17:30
To: Wang, Chaoyong
Cc: pgsql-cluster-hackers(at)postgresql(dot)org
Subject: Re: [pgsql-cluster-hackers] How to copy Datum

2012/8/21 Wang, Chaoyong <Chaoyong(dot)Wang(at)emc(dot)com>:

[..]

> But when the copied transValue is passed to the invoke function, here is
> int4_avg_accum, the ArrayType returned from PG_GETARG_ARRAYTYPE_P(0) is
> null.
>
> Which means the copy action is failed.
>
> Anybody know why? Or give me some suggestions? Thanks very much.

I suggest you ask this question on -hackers instead of here on
-cluster-hackers, as it doesn’t seem to have anything to do with
clustering.

Nicolas

--
A. Because it breaks the logical sequence of discussion.
Q. Why is top posting bad?