ok
Direktori : /opt/alt/postgresql11/usr/share/doc/alt-postgresql11-9.2.24/html/ |
Current File : //opt/alt/postgresql11/usr/share/doc/alt-postgresql11-9.2.24/html/lo-implementation.html |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >Implementation Features</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="Large Objects" HREF="largeobjects.html"><LINK REL="PREVIOUS" TITLE="Introduction" HREF="lo-intro.html"><LINK REL="NEXT" TITLE="Client Interfaces" HREF="lo-interfaces.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="SECT1" ><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="Introduction" HREF="lo-intro.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="10%" ALIGN="left" VALIGN="top" ><A HREF="largeobjects.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="60%" ALIGN="center" VALIGN="bottom" >Chapter 32. Large Objects</TD ><TD WIDTH="20%" ALIGN="right" VALIGN="top" ><A TITLE="Client Interfaces" HREF="lo-interfaces.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><DIV CLASS="SECT1" ><H1 CLASS="SECT1" ><A NAME="LO-IMPLEMENTATION" >32.2. Implementation Features</A ></H1 ><P > The large object implementation breaks large objects up into <SPAN CLASS="QUOTE" >"chunks"</SPAN > and stores the chunks in rows in the database. A B-tree index guarantees fast searches for the correct chunk number when doing random access reads and writes. </P ><P > As of <SPAN CLASS="PRODUCTNAME" >PostgreSQL</SPAN > 9.0, large objects have an owner and a set of access permissions, which can be managed using <A HREF="sql-grant.html" >GRANT</A > and <A HREF="sql-revoke.html" >REVOKE</A >. For compatibility with prior releases, see <A HREF="runtime-config-compatible.html#GUC-LO-COMPAT-PRIVILEGES" >lo_compat_privileges</A >. <TT CLASS="LITERAL" >SELECT</TT > privileges are required to read a large object, and <TT CLASS="LITERAL" >UPDATE</TT > privileges are required to write to or truncate it. Only the large object owner (or the database superuser) can unlink, comment on, or change the owner of a large object. </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="lo-intro.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="lo-interfaces.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >Introduction</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="largeobjects.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Client Interfaces</TD ></TR ></TABLE ></DIV ></BODY ></HTML >