| Server IP : 103.119.228.120 / Your IP : 18.218.38.67 Web Server : Apache System : Linux v8.techscape8.com 3.10.0-1160.119.1.el7.tuxcare.els2.x86_64 #1 SMP Mon Jul 15 12:09:18 UTC 2024 x86_64 User : nobody ( 99) PHP Version : 5.6.40 Disable Function : shell_exec,symlink,system,exec,proc_get_status,proc_nice,proc_terminate,define_syslog_variables,syslog,openlog,closelog,escapeshellcmd,passthru,ocinum cols,ini_alter,leak,listen,chgrp,apache_note,apache_setenv,debugger_on,debugger_off,ftp_exec,dl,dll,myshellexec,proc_open,socket_bind,proc_close,escapeshellarg,parse_ini_filepopen,fpassthru,exec,passthru,escapeshellarg,escapeshellcmd,proc_close,proc_open,ini_alter,popen,show_source,proc_nice,proc_terminate,proc_get_status,proc_close,pfsockopen,leak,apache_child_terminate,posix_kill,posix_mkfifo,posix_setpgid,posix_setsid,posix_setuid,dl,symlink,shell_exec,system,dl,passthru,escapeshellarg,escapeshellcmd,myshellexec,c99_buff_prepare,c99_sess_put,fpassthru,getdisfunc,fx29exec,fx29exec2,is_windows,disp_freespace,fx29sh_getupdate,fx29_buff_prepare,fx29_sess_put,fx29shexit,fx29fsearch,fx29ftpbrutecheck,fx29sh_tools,fx29sh_about,milw0rm,imagez,sh_name,myshellexec,checkproxyhost,dosyayicek,c99_buff_prepare,c99_sess_put,c99getsource,c99sh_getupdate,c99fsearch,c99shexit,view_perms,posix_getpwuid,posix_getgrgid,posix_kill,parse_perms,parsesort,view_perms_color,set_encoder_input,ls_setcheckboxall,ls_reverse_all,rsg_read,rsg_glob,selfURL,dispsecinfo,unix2DosTime,addFile,system,get_users,view_size,DirFiles,DirFilesWide,DirPrintHTMLHeaders,GetFilesTotal,GetTitles,GetTimeTotal,GetMatchesCount,GetFileMatchesCount,GetResultFiles,fs_copy_dir,fs_copy_obj,fs_move_dir,fs_move_obj,fs_rmdir,SearchText,getmicrotime MySQL : ON | cURL : ON | WGET : ON | Perl : ON | Python : ON | Sudo : ON | Pkexec : ON Directory : /usr/local/ssl/share/doc/postgresql-9.2.24/html/ |
Upload File : |
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>pg_freespacemap</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="Additional Supplied Modules"
HREF="contrib.html"><LINK
REL="PREVIOUS"
TITLE="pgcrypto"
HREF="pgcrypto.html"><LINK
REL="NEXT"
TITLE="pgrowlocks"
HREF="pgrowlocks.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="pgcrypto"
HREF="pgcrypto.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="contrib.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="60%"
ALIGN="center"
VALIGN="bottom"
>Appendix F. Additional Supplied Modules</TD
><TD
WIDTH="20%"
ALIGN="right"
VALIGN="top"
><A
TITLE="pgrowlocks"
HREF="pgrowlocks.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="PGFREESPACEMAP"
>F.26. pg_freespacemap</A
></H1
><P
> The <TT
CLASS="FILENAME"
>pg_freespacemap</TT
> module provides a means for examining the
free space map (FSM). It provides a function called
<CODE
CLASS="FUNCTION"
>pg_freespace</CODE
>, or two overloaded functions, to be
precise. The functions show the value recorded in the free space map for
a given page, or for all pages in the relation.
</P
><P
> By default public access is revoked from the functions, just in case
there are security issues lurking.
</P
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN150875"
>F.26.1. Functions</A
></H2
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><CODE
CLASS="FUNCTION"
>pg_freespace(rel regclass IN, blkno bigint IN) returns int2</CODE
></DT
><DD
><P
> Returns the amount of free space on the page of the relation, specified
by <TT
CLASS="LITERAL"
>blkno</TT
>, according to the FSM.
</P
></DD
><DT
><CODE
CLASS="FUNCTION"
>pg_freespace(rel regclass IN, blkno OUT bigint, avail OUT int2)</CODE
></DT
><DD
><P
> Displays the amount of free space on each page of the relation,
according to the FSM. A set of <TT
CLASS="LITERAL"
>(blkno bigint, avail int2)</TT
>
tuples is returned, one tuple for each page in the relation.
</P
></DD
></DL
></DIV
><P
> The values stored in the free space map are not exact. They're rounded
to precision of 1/256th of <TT
CLASS="SYMBOL"
>BLCKSZ</TT
> (32 bytes with default <TT
CLASS="SYMBOL"
>BLCKSZ</TT
>), and
they're not kept fully up-to-date as tuples are inserted and updated.
</P
><P
> For indexes, what is tracked is entirely-unused pages, rather than free
space within pages. Therefore, the values are not meaningful, just
whether a page is full or empty.
</P
><P
> NOTE: The interface was changed in version 8.4, to reflect the new FSM
implementation introduced in the same version.
</P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN150895"
>F.26.2. Sample Output</A
></H2
><PRE
CLASS="SCREEN"
>postgres=# SELECT * FROM pg_freespace('foo');
blkno | avail
-------+-------
0 | 0
1 | 0
2 | 0
3 | 32
4 | 704
5 | 704
6 | 704
7 | 1216
8 | 704
9 | 704
10 | 704
11 | 704
12 | 704
13 | 704
14 | 704
15 | 704
16 | 704
17 | 704
18 | 704
19 | 3648
(20 rows)
postgres=# SELECT * FROM pg_freespace('foo', 7);
pg_freespace
--------------
1216
(1 row)</PRE
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN150898"
>F.26.3. Author</A
></H2
><P
> Original version by Mark Kirkwood <CODE
CLASS="EMAIL"
><<A
HREF="mailto:markir@paradise.net.nz"
>markir@paradise.net.nz</A
>></CODE
>.
Rewritten in version 8.4 to suit new FSM implementation by Heikki
Linnakangas <CODE
CLASS="EMAIL"
><<A
HREF="mailto:heikki@enterprisedb.com"
>heikki@enterprisedb.com</A
>></CODE
>
</P
></DIV
></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="pgcrypto.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="pgrowlocks.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>pgcrypto</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="contrib.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>pgrowlocks</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>