Skip site navigation (1) Skip section navigation (2)

How to change/replace an in-memory palloced tuple- tuple data

From: Fx <weimaraner(at)gmail(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Subject: How to change/replace an in-memory palloced tuple- tuple data
Date: 2004-09-20 17:32:09
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-hackers
Hi there , 
             i have this scenario :

- postgresql 7.5 ( with modified heap_*  functions to retrieve data
from another dbms)
- the tuple's data is allocated in memory via palloc 
   (the  tuple table slot and the heap tuple hold a pointer to the
data and not to the buffer pages nor hard disk data pointers)
- the changes (by now) gonna be implemented in  sequential scans. 

Having these , I need to modify the tuple after the ExecQual , and
after the projection so i can save memory , just changing the tuple to
hold a "hash" or compressed data , and decompress / or restore the
tuple data  in the ExecSelect phase.

I tried to do this using  the heap_modifytuple function , and
returning a "newSlot  with a newTuple" instead the "resultSlot" but as
i suppose im missing something  , can anyone help me ? or give me a

Thanks in advance..
/* Jumping Flowers */


pgsql-hackers by date

Next:From: Joe ConwayDate: 2004-09-20 17:55:56
Subject: Re: schema level variables and deferrable unique constraints
Previous:From: Tom LaneDate: 2004-09-20 17:29:01
Subject: Re: No parameters support in "create user"?

Privacy Policy | About PostgreSQL
Copyright © 1996-2017 The PostgreSQL Global Development Group