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Re: Execution Plan

From: "Simon Riggs" <simon(at)2ndquadrant(dot)com>
To: "alfranio correia junior" <alfranio(at)lsd(dot)di(dot)uminho(dot)pt>
Cc: <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Execution Plan
Date: 2007-01-03 21:13:16
Message-ID: 1167858797.3903.614.camel@silverbirch.site (view raw or flat)
Thread:
Lists: pgsql-hackers
On Wed, 2007-01-03 at 19:44 +0000, alfranio correia junior wrote:

> I have some questions on execution plans.
> 
> When are the following plans used ?
> 
> nodeFunctionscan.c 

When there is a Set Returning Function emitting tuples.

>   nodeTidscan.c

When there is a query that accesses data using a direct TID, 
e.g. WHERE ctid = '(5,12)'

this is most frequently found in calls made through the ODBC driver when
it uses its client-side implementation of updateable cursors. This is
only used these days when we have a multi-statement request, so is
mostly unused now.

> In particular, is the plan nodeBitmapHeapscan.c always used along with 
> the nodeBitmapIndexscan.c ?

Yes

> Please, let me know if there is a previous thread on this subject or any 
> document available.

Try src/backend/executor readme and code comments, plus the main docs
are reasonable. Documentation always welcome.

-- 
  Simon Riggs             
  EnterpriseDB   http://www.enterprisedb.com



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