mirror of
https://git.postgresql.org/git/postgresql.git
synced 2025-03-01 19:45:33 +08:00
Rename the built-in tablespaces to pg_default and pg_global, and prohibit
creation of user-defined tablespaces with names starting with 'pg_', as per suggestion of Chris K-L. Also install admin-guide tablespace documentation from Gavin.
This commit is contained in:
Tom Lane
parent
483b7f8249
commit
f5f448fb3e
@ -1,5 +1,5 @@
|
||||
<!--
|
||||
$PostgreSQL: pgsql/doc/src/sgml/diskusage.sgml,v 1.10 2003/11/29 19:51:36 pgsql Exp $
|
||||
$PostgreSQL: pgsql/doc/src/sgml/diskusage.sgml,v 1.11 2004/06/21 04:06:03 tgl Exp $
|
||||
-->
|
||||
|
||||
<chapter id="diskusage">
|
||||
@ -124,20 +124,15 @@ SELECT relname, relpages FROM pg_class ORDER BY relpages DESC;
|
||||
|
||||
<para>
|
||||
If you cannot free up additional space on the disk by deleting
|
||||
other things you can move some of the database files to other file
|
||||
systems and create a symlink from the original location. But
|
||||
note that <application>pg_dump</> cannot save the location layout
|
||||
information of such a setup; a restore would put everything back in
|
||||
one place. To avoid running out of disk space, you can place the
|
||||
WAL files or individual databases in other locations while creating
|
||||
them. See the <command>initdb</> documentation and <xref
|
||||
linkend="manage-ag-alternate-locs"> for more information about that.
|
||||
other things, you can move some of the database files to other file
|
||||
systems by making use of tablespaces. See <xref
|
||||
linkend="manage-ag-tablespaces"> for more information about that.
|
||||
</para>
|
||||
|
||||
<tip>
|
||||
<para>
|
||||
Some file systems perform badly when they are almost full, so do
|
||||
not wait until the disk is full to take action.
|
||||
not wait until the disk is completely full to take action.
|
||||
</para>
|
||||
</tip>
|
||||
</sect1>
|
||||
|
||||
@ -1,5 +1,5 @@
|
||||
<!--
|
||||
$PostgreSQL: pgsql/doc/src/sgml/manage-ag.sgml,v 2.30 2004/06/18 06:13:02 tgl Exp $
|
||||
$PostgreSQL: pgsql/doc/src/sgml/manage-ag.sgml,v 2.31 2004/06/21 04:06:03 tgl Exp $
|
||||
-->
|
||||
|
||||
<chapter id="managing-databases">
|
||||
@ -295,86 +295,6 @@ ALTER DATABASE mydb SET geqo TO off;
|
||||
</para>
|
||||
</sect1>
|
||||
|
||||
<sect1 id="manage-ag-alternate-locs">
|
||||
<title>Alternative Locations</title>
|
||||
|
||||
<para>
|
||||
XXX this is entirely dead now, and needs to be replaced by a DBA-level
|
||||
description of tablespaces.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
It is possible to create a database in a location other than the
|
||||
default location for the installation. But remember that all database access
|
||||
occurs through the
|
||||
database server, so any location specified must be
|
||||
accessible by the server.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Alternative database locations are referenced by an environment
|
||||
variable which gives the absolute path to the intended storage
|
||||
location. This environment variable must be present in the server's
|
||||
environment, so it must have been defined before the server
|
||||
was started. (Thus, the set of available alternative locations is
|
||||
under the site administrator's control; ordinary users can't
|
||||
change it.) Any valid environment variable name may
|
||||
be used to reference an alternative location, although using
|
||||
variable names with a prefix of <literal>PGDATA</> is recommended
|
||||
to avoid confusion and conflict with other variables.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
To create the variable in the environment of the server process
|
||||
you must first shut down the server, define the variable,
|
||||
initialize the data area, and finally restart the server. (See also
|
||||
<xref linkend="postmaster-shutdown"> and <xref
|
||||
linkend="postmaster-start">.) To set an environment variable, type
|
||||
<programlisting>
|
||||
PGDATA2=/home/postgres/data
|
||||
export PGDATA2
|
||||
</programlisting>
|
||||
in Bourne shells, or
|
||||
<programlisting>
|
||||
setenv PGDATA2 /home/postgres/data
|
||||
</programlisting>
|
||||
in <command>csh</> or <command>tcsh</>. You have to make sure that this environment
|
||||
variable is always defined in the server environment, otherwise
|
||||
you won't be able to access that database. Therefore you probably
|
||||
want to set it in some sort of shell start-up file or server
|
||||
start-up script.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
<indexterm><primary>initlocation</></>
|
||||
To create a data storage area in <envar>PGDATA2</>, ensure that
|
||||
the containing directory (here, <filename>/home/postgres</filename>)
|
||||
already exists and is writable
|
||||
by the user account that runs the server (see <xref
|
||||
linkend="postgres-user">). Then from the command line, type
|
||||
<programlisting>
|
||||
initlocation PGDATA2
|
||||
</programlisting>
|
||||
(<emphasis>not</emphasis> <literal>initlocation
|
||||
$PGDATA2</literal>). Then you can restart the server.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
To create a database within the new location, use the command
|
||||
<synopsis>
|
||||
CREATE DATABASE <replaceable>name</> WITH LOCATION '<replaceable>location</>';
|
||||
</synopsis>
|
||||
where <replaceable>location</> is the environment variable you
|
||||
used, <envar>PGDATA2</> in this example. The <command>createdb</>
|
||||
command has the option <option>-D</> for this purpose.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Databases created in alternative locations can be
|
||||
accessed and dropped like any other database.
|
||||
</para>
|
||||
</sect1>
|
||||
|
||||
<sect1 id="manage-ag-dropdb">
|
||||
<title>Destroying a Database</title>
|
||||
|
||||
@ -410,6 +330,116 @@ dropdb <replaceable class="parameter">dbname</replaceable>
|
||||
the database with the current user name.)
|
||||
</para>
|
||||
</sect1>
|
||||
|
||||
<sect1 id="manage-ag-tablespaces">
|
||||
<title>Tablespaces</title>
|
||||
|
||||
<para>
|
||||
Tablespaces in <productname>PostgreSQL</> allow database superusers to
|
||||
define locations in the file system where the files representing
|
||||
database objects can be stored. Once created, a tablespace can be referred
|
||||
to by name when creating database objects.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
By using tablespaces, a database administrator can control the disk
|
||||
layout of a <productname>PostgreSQL</> installation. This is useful in
|
||||
at least two ways. Firstly, if the partition or volume on which the cluster
|
||||
was initialized runs out of space and cannot be extended logically
|
||||
or otherwise, a tablespace can be created on a different partition
|
||||
and used until the system can be reconfigured.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Secondly, tablespaces allow a database administrator to arrange data
|
||||
locations based on the usage patterns of database objects. For
|
||||
example, an index which is very heavily used can be placed on very fast,
|
||||
highly available disk, such as an expensive solid state device. At the same
|
||||
time a table storing archived data which is rarely used or not performance
|
||||
critical could be stored on a less expensive, slower disk system.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Databases, schemas, tables, indexes and sequences can all be placed in
|
||||
particular tablespaces. To do so, a user with the <literal>CREATE</>
|
||||
privilege on a given tablespace must pass the tablespace name as a
|
||||
parameter to the relevant command. For example, the following creates
|
||||
a table in the tablespace <literal>space1</>:
|
||||
<programlisting>
|
||||
CREATE TABLE foo(i int) TABLESPACE space1;
|
||||
</programlisting>
|
||||
</para>
|
||||
|
||||
<para>
|
||||
The tablespace associated with a database is used to store the system
|
||||
catalogs of that database, as well as any temporary files created by
|
||||
server processes using that database. Furthermore, it is the default
|
||||
tablespace selected for any objects created within the database, if
|
||||
no specific <literal>TABLESPACE</> clause is given when those objects
|
||||
are created. If a database is created without specifying a tablespace
|
||||
for it, it uses the same tablespace as the template database it is copied
|
||||
from.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
A schema does not in itself occupy any storage (other than a system
|
||||
catalog entry), so assigning a tablespace to a schema does not in itself
|
||||
do anything. What this actually does is to set a default tablespace
|
||||
for tables, indexes, and sequences later created within the schema. If
|
||||
no tablespace is mentioned when creating a schema, it inherits its
|
||||
default tablespace from the current database.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
The default choice of tablespace for an index is the same tablespace
|
||||
already assigned to the table the index is for.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Another way to state the above rules is that when a schema, table, index
|
||||
or sequence is created without specifying a tablespace, the object
|
||||
inherits its logical parent's tablespace. A schema will be created in the
|
||||
current database's tablespace; a table or sequence will be created in the
|
||||
tablespace of the schema it is being created in; an index will be created
|
||||
in the tablespace of the table underlying the index.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Two tablespaces are automatically created by <literal>initdb</>. The
|
||||
<literal>pg_global</> tablespace is used for shared system catalogs. The
|
||||
<literal>pg_default</> tablespace is the default tablespace of the
|
||||
<literal>template1</> and <literal>template0</> databases (and, therefore,
|
||||
will be the default tablespace for everything else as well, unless
|
||||
explicit <literal>TABLESPACE</> clauses are used somewhere along the
|
||||
line).
|
||||
</para>
|
||||
|
||||
<para>
|
||||
Once created, a tablespace can be used from any database, provided
|
||||
the requesting user has sufficient privilege. This means that a tablespace
|
||||
cannot be dropped until all objects in all databases using the tablespace
|
||||
have been removed.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
To simplify the implementation of tablespaces,
|
||||
<productname>PostgreSQL</> makes extensive use of symbolic links. This
|
||||
means that tablespaces can be used <emphasis>only</> on systems
|
||||
that support symbolic links.
|
||||
</para>
|
||||
|
||||
<para>
|
||||
The directory <filename>$PGDATA/pg_tblspc</> contains symbolic links that
|
||||
point to each of the non-built-in tablespaces defined in the cluster.
|
||||
Although not recommended, it is possible to adjust the tablespace
|
||||
layout by hand by redefining these links. Two warnings: do not do so
|
||||
while the postmaster is running; and after you restart the postmaster,
|
||||
update the <structname>pg_tablespace</> catalog to show the new
|
||||
locations. (If you do not, <literal>pg_dump</> will continue to show
|
||||
the old tablespace locations.)
|
||||
</para>
|
||||
|
||||
</sect1>
|
||||
</chapter>
|
||||
|
||||
<!-- Keep this comment at the end of the file
|
||||
|
||||
@ -1,5 +1,5 @@
|
||||
<!--
|
||||
$PostgreSQL: pgsql/doc/src/sgml/ref/postmaster.sgml,v 1.49 2004/03/23 06:09:00 neilc Exp $
|
||||
$PostgreSQL: pgsql/doc/src/sgml/ref/postmaster.sgml,v 1.50 2004/06/21 04:06:04 tgl Exp $
|
||||
PostgreSQL documentation
|
||||
-->
|
||||
|
||||
@ -417,18 +417,6 @@ PostgreSQL documentation
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
<varlistentry>
|
||||
<term>others</term>
|
||||
|
||||
<listitem>
|
||||
<para>
|
||||
Other environment variables may be used to designate alternative
|
||||
data storage locations. See <xref linkend="manage-ag-alternate-locs"> for more
|
||||
information.
|
||||
</para>
|
||||
</listitem>
|
||||
</varlistentry>
|
||||
|
||||
</variablelist>
|
||||
</refsect1>
|
||||
|
||||
|
||||
@ -9,7 +9,7 @@
|
||||
*
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $PostgreSQL: pgsql/src/backend/catalog/catalog.c,v 1.53 2004/06/21 01:04:41 momjian Exp $
|
||||
* $PostgreSQL: pgsql/src/backend/catalog/catalog.c,v 1.54 2004/06/21 04:06:05 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
@ -119,8 +119,7 @@ GetDatabasePath(Oid dbNode, Oid spcNode)
|
||||
*
|
||||
* We now just test if the relation is in the system catalog namespace;
|
||||
* so it's no longer necessary to forbid user relations from having
|
||||
* names starting with pg_. Now only schema names have the pg_
|
||||
* distinction/requirement.
|
||||
* names starting with pg_.
|
||||
*/
|
||||
bool
|
||||
IsSystemRelation(Relation relation)
|
||||
@ -200,8 +199,8 @@ IsToastNamespace(Oid namespaceId)
|
||||
* True iff name starts with the pg_ prefix.
|
||||
*
|
||||
* For some classes of objects, the prefix pg_ is reserved for
|
||||
* system objects only. As of 7.3, this is now only true for
|
||||
* schema names.
|
||||
* system objects only. As of 7.5, this is only true for
|
||||
* schema and tablespace names.
|
||||
*/
|
||||
bool
|
||||
IsReservedName(const char *name)
|
||||
|
||||
@ -19,8 +19,8 @@
|
||||
* Thus the full path to an arbitrary file is
|
||||
* $PGDATA/pg_tblspc/spcoid/dboid/relfilenode
|
||||
*
|
||||
* There are two tablespaces created at initdb time: global (for shared
|
||||
* tables) and default (for everything else). For backwards compatibility
|
||||
* There are two tablespaces created at initdb time: pg_global (for shared
|
||||
* tables) and pg_default (for everything else). For backwards compatibility
|
||||
* and to remain functional on platforms without symlinks, these tablespaces
|
||||
* are accessed specially: they are respectively
|
||||
* $PGDATA/global/relfilenode
|
||||
@ -45,7 +45,7 @@
|
||||
*
|
||||
*
|
||||
* IDENTIFICATION
|
||||
* $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.2 2004/06/21 01:04:42 momjian Exp $
|
||||
* $PostgreSQL: pgsql/src/backend/commands/tablespace.c,v 1.3 2004/06/21 04:06:06 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
@ -233,6 +233,17 @@ CreateTableSpace(CreateTableSpaceStmt *stmt)
|
||||
errmsg("tablespace location \"%s\" is too long",
|
||||
location)));
|
||||
|
||||
/*
|
||||
* Disallow creation of tablespaces named "pg_xxx"; we reserve this
|
||||
* namespace for system purposes.
|
||||
*/
|
||||
if (!allowSystemTableMods && IsReservedName(stmt->tablespacename))
|
||||
ereport(ERROR,
|
||||
(errcode(ERRCODE_RESERVED_NAME),
|
||||
errmsg("unacceptable tablespace name \"%s\"",
|
||||
stmt->tablespacename),
|
||||
errdetail("The prefix \"pg_\" is reserved for system tablespaces.")));
|
||||
|
||||
/*
|
||||
* Check that there is no other tablespace by this name. (The
|
||||
* unique index would catch this anyway, but might as well give
|
||||
|
||||
@ -37,7 +37,7 @@
|
||||
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
||||
*
|
||||
* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.238 2004/06/21 01:04:45 momjian Exp $
|
||||
* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.239 2004/06/21 04:06:07 tgl Exp $
|
||||
*
|
||||
*-------------------------------------------------------------------------
|
||||
*/
|
||||
@ -53,6 +53,6 @@
|
||||
*/
|
||||
|
||||
/* yyyymmddN */
|
||||
#define CATALOG_VERSION_NO 200406201
|
||||
#define CATALOG_VERSION_NO 200406202
|
||||
|
||||
#endif
|
||||
|
||||
@ -8,7 +8,7 @@
|
||||
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
|
||||
* Portions Copyright (c) 1994, Regents of the University of California
|
||||
*
|
||||
* $PostgreSQL: pgsql/src/include/catalog/pg_tablespace.h,v 1.1 2004/06/18 06:14:06 tgl Exp $
|
||||
* $PostgreSQL: pgsql/src/include/catalog/pg_tablespace.h,v 1.2 2004/06/21 04:06:07 tgl Exp $
|
||||
*
|
||||
* NOTES
|
||||
* the genbki.sh script reads this file and generates .bki
|
||||
@ -57,8 +57,8 @@ typedef FormData_pg_tablespace *Form_pg_tablespace;
|
||||
#define Anum_pg_tablespace_spclocation 3
|
||||
#define Anum_pg_tablespace_spcacl 4
|
||||
|
||||
DATA(insert OID = 1663 ( default PGUID "" _null_ ));
|
||||
DATA(insert OID = 1664 ( global PGUID "" _null_ ));
|
||||
DATA(insert OID = 1663 ( pg_default PGUID "" _null_ ));
|
||||
DATA(insert OID = 1664 ( pg_global PGUID "" _null_ ));
|
||||
|
||||
#define DEFAULTTABLESPACE_OID 1663
|
||||
#define GLOBALTABLESPACE_OID 1664
|
||||
|
||||
Loading…
Reference in New Issue
Block a user