Execution Plan

Started by alfranio correia juniorabout 19 years ago2 messages
#1alfranio correia junior
alfranio@lsd.di.uminho.pt

Hi,

I have some questions on execution plans.

When are the following plans used ?

nodeFunctionscan.c nodeTidscan.c

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

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

Best regards,

Alfranio.

#2Simon Riggs
simon@2ndquadrant.com
In reply to: alfranio correia junior (#1)
Re: Execution Plan

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