Re: need help in understanding gist function - Mailing list pgsql-hackers

From Teodor Sigaev
Subject Re: need help in understanding gist function
Date
Msg-id 45F801A6.7010509@sigaev.ru
Whole thread Raw
In response to need help in understanding gist function  ("sharath kumar" <k.sharat@gmail.com>)
List pgsql-hackers
> 1. What is the functionality of gistplacetopage() function in gist.c 
> ?Can you please give me detail description of this function.

It tries to place index tuple on page. If page hasn't enough space, 
gistplacetopage splits page on two or more pages. Number of page to be splitted 
depends, basically, on quality of user-defined picksplit and distribution of 
tuple's length.

> 2. I have left and right buffers with values that I have filled. Now, 
> how do I write these changes(buffers) permanently into gistentry pages?
Sorry, I don't understand your questions. Where you have left and right buffers?
Real write are produced by bgwriter process, in backend we should just mark 
byffer as dirty with a help of  MarkBufferDirty call.



-- 
Teodor Sigaev                                   E-mail: teodor@sigaev.ru
  WWW: http://www.sigaev.ru/
 


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