Re: [HACKERS] 2WRS [WIP]

Referring to tuplesort.c   and    tuplestore.c

BACKGROUND: Starting from dumptuples()  [ tuplesort.c ] write functions move
the tuple from a buffer to another in order to finally write it in a logical
tape. Is there a way (even the most inefficient way) to use current
read/write functions provided by PostgreSQL in order to retrieve the first
tuple of a certain run while performing External Sorting?

NOTE: I need the first tuple in order to manipulate the whole corresponding
run, tuple by tuple since they are written sequentially in a run.

Thanks for your attention.
Regards, Manolo.


--------------------------------------------------
From: <manolo.espa@gmail.com>
Sent: Tuesday, February 26, 2008 4:10 PM
To: "Jaime Casanova" <systemguards@gmail.com>; <manolo.espa@gmail.com>
Cc: "Decibel!" <decibel@decibel.org>; "David Fetter" <david@fetter.org>;
<pgsql-patches@postgresql.org>; <pgsql-hackers@postgresql.org>
Subject: Re: [HACKERS] [PATCHES] 2WRS [WIP]

> For the joy of all of you: that's the correct WIP patch.
> At the moment it only tries to create runs uding two heaps. Hope you can
> help me with writing those runs on tapes.
>
> I'd be very pleased to give you more details.
>
> Thenks for your time.
> Regards, Manolo.
>
>
> --------------------------------------------------
> From: "Jaime Casanova" <systemguards@gmail.com>
> Sent: Friday, February 22, 2008 5:30 AM
> To: <manolo.espa@gmail.com>
> Cc: "Decibel!" <decibel@decibel.org>; "Manolo _" <mac_man2005@hotmail.it>;
> "David Fetter" <david@fetter.org>; <pgsql-patches@postgresql.org>;
> <pgsql-hackers@postgresql.org>
> Subject: Re: [HACKERS] [PATCHES] 2WRS [WIP]
>
>> On Thu, Feb 21, 2008 at 6:44 AM,  <manolo.espa@gmail.com> wrote:
>>> Hi.
>>>
>>> That's the last release and refers to 8.3.0 and not to 8.2.5 as before.
>>> Hope
>>> you can tell me if I created it correctly please.
>>>
>>
>> no, it doesn't...
>>
>>> ! /* GUC variables */
>>>   #ifdef TRACE_SORT
>>>   bool trace_sort = false;
>>>   #endif
>>> - #ifdef DEBUG_BOUNDED_SORT
>>> - bool optimize_bounded_sort = true;
>>> - #endif
>>
>> it's seems you're removing something added in 8.3
>>
>> --
>> regards,
>> Jaime Casanova
>>
>> "Programming today is a race between software engineers striving to
>> build bigger and better idiot-proof programs and the universe trying
>> to produce bigger and better idiots.
>> So far, the universe is winning."
>> Richard Cook
>>
>> ---------------------------(end of broadcast)---------------------------
>> TIP 9: In versions below 8.0, the planner will ignore your desire to
>>       choose an index scan if your joining column's datatypes do not
>>       match
>>