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
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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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