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From: Bruce Momjian <[email protected]>
To: Craig Ringer <[email protected]>
Cc: Ian Lawrence Barwick <[email protected]>
Cc: PostgreSQL Developers <[email protected]>
Subject: Re: PATCH: Warn users about tablespace abuse data loss risk
Date: Sat, 19 Apr 2014 10:53:29 -0400
Message-ID: <[email protected]> (raw)
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On Thu, Feb 13, 2014 at 08:15:59AM +0800, Craig Ringer wrote:
> On 02/12/2014 02:35 PM, Ian Lawrence Barwick wrote:
> > And taking a look at the page in question I see this prominent example:
> > 
> >   CREATE TABLESPACE fastspace LOCATION '/mnt/sda1/postgresql/data';
> 
> Here's an updated patch, adopting your wording for the first par and
> tweaking the example.

I have applied an adjusted version of this patch that is more compact. 
Thanks.

-- 
  Bruce Momjian  <[email protected]>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + Everyone has their own god. +


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Attachments:

  [text/x-diff] tablespace.diff (3.0K, 2-tablespace.diff)
  download | inline diff:
diff --git a/doc/src/sgml/manage-ag.sgml b/doc/src/sgml/manage-ag.sgml
new file mode 100644
index b44d521..78ec509
*** a/doc/src/sgml/manage-ag.sgml
--- b/doc/src/sgml/manage-ag.sgml
*************** dropdb <replaceable class="parameter">db
*** 379,395 ****
     expensive, slower disk system.
    </para>
  
    <para>
     To define a tablespace, use the <xref
     linkend="sql-createtablespace">
     command, for example:<indexterm><primary>CREATE TABLESPACE</></>:
  <programlisting>
! CREATE TABLESPACE fastspace LOCATION '/mnt/sda1/postgresql/data';
  </programlisting>
     The location must be an existing, empty directory that is owned by
     the <productname>PostgreSQL</> operating system user.  All objects subsequently
     created within the tablespace will be stored in files underneath this
!    directory.
    </para>
  
    <note>
--- 379,412 ----
     expensive, slower disk system.
    </para>
  
+   <warning>
+    <para>
+      Even though located outside the main PostgreSQL data directory,
+      tablespaces are an integral part of the database cluster and
+      <emphasis>cannot</emphasis> be treated as an autonomous collection
+      of data files. They are dependent on metadata contained in the main
+      data directory, and therefore cannot be attached to a different
+      database cluster or backed up individually.  Similarly, if you lose
+      a tablespace (file deletion, disk failure, etc), the database cluster
+      might become unreadable or unable to start.  Placing a tablespace
+      on a temporary file system like a ramdisk risks the reliability of
+      the entire cluster.
+    </para>
+   </warning>
+ 
    <para>
     To define a tablespace, use the <xref
     linkend="sql-createtablespace">
     command, for example:<indexterm><primary>CREATE TABLESPACE</></>:
  <programlisting>
! CREATE TABLESPACE fastspace LOCATION '/ssd1/postgresql/data';
  </programlisting>
     The location must be an existing, empty directory that is owned by
     the <productname>PostgreSQL</> operating system user.  All objects subsequently
     created within the tablespace will be stored in files underneath this
!    directory.  The location must not be on removable or transient storage,
!    as the cluster might fail to function if the tablespace is missing
!    or lost.
    </para>
  
    <note>
diff --git a/doc/src/sgml/ref/create_tablespace.sgml b/doc/src/sgml/ref/create_tablespace.sgml
new file mode 100644
index b643565..cf6215e
*** a/doc/src/sgml/ref/create_tablespace.sgml
--- b/doc/src/sgml/ref/create_tablespace.sgml
*************** CREATE TABLESPACE <replaceable class="pa
*** 50,55 ****
--- 50,63 ----
     <command>CREATE INDEX</> or <command>ADD CONSTRAINT</> to have the data
     files for these objects stored within the specified tablespace.
    </para>
+ 
+   <warning>
+    <para>
+     A tablespace cannot be used independently of the cluster in which it
+     is defined;  see <xref linkend="manage-ag-tablespaces"/>.
+    </para>
+   </warning>
+ 
   </refsect1>
  
   <refsect1>

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