Re: Doubt in parser

[Michael Glaesemann <grzm(at)myrealbox(dot)com>]

On Feb 16, 2006, at 21:37 , Dhanaraj wrote:

> hi
>
> currently i looking at the postgres src code. I saw the scanner and  
> parser implemetations at two different places (src/backend/parser/   
> and  /src/bakend/bootstrp). Can anybody tell me the purpose of  
> having two phases?? or will this help to parse the queries at  
> different levels?

AFAIK, I don't think the code is exactly the same (though I haven't  
checked). The bootstrap code is used to get the PostgreSQL server  
started: there is a considerable amount of information stored in the  
system catalogs that the server needs to use. The server needs access  
to a scanner/parser to be able to read this information. The  
bootstrap code provides the server with enough knowledge to get  
started. The backend parser and scanner is more feature-filled.

Someone please feel free to step in and correct me if I'm off base :)

Michael Glaesemann
grzm myrealbox com