MAINHACK

Viewing / Editing File: planner-stats-details.html

File is not writable. Editing disabled.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>How the Planner Uses Statistics</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
REV="MADE"
HREF="mailto:pgsql-docs@postgresql.org"><LINK
REL="HOME"
TITLE="PostgreSQL 9.2.24 Documentation"
HREF="index.html"><LINK
REL="UP"
TITLE="Internals"
HREF="internals.html"><LINK
REL="PREVIOUS"
TITLE="Example"
HREF="bki-example.html"><LINK
REL="NEXT"
TITLE="Row Estimation Examples"
HREF="row-estimation-examples.html"><LINK
REL="STYLESHEET"
TYPE="text/css"
HREF="stylesheet.css"><META
HTTP-EQUIV="Content-Type"
CONTENT="text/html; charset=ISO-8859-1"><META
NAME="creation"
CONTENT="2017-11-06T22:43:11"></HEAD
><BODY
CLASS="CHAPTER"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="5"
ALIGN="center"
VALIGN="bottom"
><A
HREF="index.html"
>PostgreSQL 9.2.24 Documentation</A
></TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
TITLE="Example"
HREF="bki-example.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="internals.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="60%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="20%"
ALIGN="right"
VALIGN="top"
><A
TITLE="Row Estimation Examples"
HREF="row-estimation-examples.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="CHAPTER"
><H1
><A
NAME="PLANNER-STATS-DETAILS"
></A
>Chapter 58. How the Planner Uses Statistics</H1
><DIV
CLASS="TOC"
><DL
><DT
><B
>Table of Contents</B
></DT
><DT
>58.1. <A
HREF="row-estimation-examples.html"
>Row Estimation Examples</A
></DT
><DT
>58.2. <A
HREF="planner-stats-security.html"
>Planner Statistics and Security</A
></DT
></DL
></DIV
><P
>   This chapter builds on the material covered in <A
HREF="using-explain.html"
>Section 14.1</A
> and <A
HREF="planner-stats.html"
>Section 14.2</A
> to show some
   additional details about how the planner uses the
   system statistics to estimate the number of rows each part of a query might
   return. This is a significant part of the planning process,
   providing much of the raw material for cost calculation.
  </P
><P
>   The intent of this chapter is not to document the code in detail,
   but to present an overview of how it works.
   This will perhaps ease the learning curve for someone who subsequently
   wishes to read the code.
  </P
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="bki-example.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="row-estimation-examples.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Example</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="internals.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Row Estimation Examples</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>
Cancel / Back
[ MAINHACK ]

Viewing / Editing File: planner-stats-details.html

Server Info

System Features

User Info
