mirror of
https://github.com/zebrajr/postgres.git
synced 2025-12-06 12:20:15 +01:00
When implementing a replication solution ontop of logical decoding, two
related problems exist:
* How to safely keep track of replication progress
* How to change replication behavior, based on the origin of a row;
e.g. to avoid loops in bi-directional replication setups
The solution to these problems, as implemented here, consist out of
three parts:
1) 'replication origins', which identify nodes in a replication setup.
2) 'replication progress tracking', which remembers, for each
replication origin, how far replay has progressed in a efficient and
crash safe manner.
3) The ability to filter out changes performed on the behest of a
replication origin during logical decoding; this allows complex
replication topologies. E.g. by filtering all replayed changes out.
Most of this could also be implemented in "userspace", e.g. by inserting
additional rows contain origin information, but that ends up being much
less efficient and more complicated. We don't want to require various
replication solutions to reimplement logic for this independently. The
infrastructure is intended to be generic enough to be reusable.
This infrastructure also replaces the 'nodeid' infrastructure of commit
timestamps. It is intended to provide all the former capabilities,
except that there's only 2^16 different origins; but now they integrate
with logical decoding. Additionally more functionality is accessible via
SQL. Since the commit timestamp infrastructure has also been introduced
in 9.5 (commit 73c986add) changing the API is not a problem.
For now the number of origins for which the replication progress can be
tracked simultaneously is determined by the max_replication_slots
GUC. That GUC is not a perfect match to configure this, but there
doesn't seem to be sufficient reason to introduce a separate new one.
Bumps both catversion and wal page magic.
Author: Andres Freund, with contributions from Petr Jelinek and Craig Ringer
Reviewed-By: Heikki Linnakangas, Petr Jelinek, Robert Haas, Steve Singer
Discussion: 20150216002155.GI15326@awork2.anarazel.de,
20140923182422.GA15776@alap3.anarazel.de,
20131114172632.GE7522@alap2.anarazel.de
280 lines
7.7 KiB
Plaintext
280 lines
7.7 KiB
Plaintext
<!-- doc/src/sgml/postgres.sgml -->
|
|
|
|
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook V4.2//EN" [
|
|
|
|
<!ENTITY % version SYSTEM "version.sgml">
|
|
%version;
|
|
<!ENTITY % filelist SYSTEM "filelist.sgml">
|
|
%filelist;
|
|
|
|
<!ENTITY reference SYSTEM "reference.sgml">
|
|
|
|
]>
|
|
|
|
<book id="postgres">
|
|
<title>PostgreSQL &version; Documentation</title>
|
|
|
|
<bookinfo>
|
|
<corpauthor>The PostgreSQL Global Development Group</corpauthor>
|
|
<productname>PostgreSQL</productname>
|
|
<productnumber>&version;</productnumber>
|
|
&legal;
|
|
</bookinfo>
|
|
|
|
&intro;
|
|
|
|
<part id="tutorial">
|
|
<title>Tutorial</title>
|
|
|
|
<partintro>
|
|
<para>
|
|
Welcome to the <productname>PostgreSQL</productname> Tutorial. The
|
|
following few chapters are intended to give a simple introduction
|
|
to <productname>PostgreSQL</productname>, relational database
|
|
concepts, and the SQL language to those who are new to any one of
|
|
these aspects. We only assume some general knowledge about how to
|
|
use computers. No particular Unix or programming experience is
|
|
required. This part is mainly intended to give you some hands-on
|
|
experience with important aspects of the
|
|
<productname>PostgreSQL</productname> system. It makes no attempt
|
|
to be a complete or thorough treatment of the topics it covers.
|
|
</para>
|
|
|
|
<para>
|
|
After you have worked through this tutorial you might want to move
|
|
on to reading <xref linkend="sql"> to gain a more formal knowledge
|
|
of the SQL language, or <xref linkend="client-interfaces"> for
|
|
information about developing applications for
|
|
<productname>PostgreSQL</productname>. Those who set up and
|
|
manage their own server should also read <xref linkend="admin">.
|
|
</para>
|
|
</partintro>
|
|
|
|
&start;
|
|
&query;
|
|
&advanced;
|
|
|
|
</part>
|
|
|
|
<part id="sql">
|
|
<title>The SQL Language</title>
|
|
|
|
<partintro>
|
|
<para>
|
|
This part describes the use of the <acronym>SQL</acronym> language
|
|
in <productname>PostgreSQL</productname>. We start with
|
|
describing the general syntax of <acronym>SQL</acronym>, then
|
|
explain how to create the structures to hold data, how to populate
|
|
the database, and how to query it. The middle part lists the
|
|
available data types and functions for use in
|
|
<acronym>SQL</acronym> commands. The rest treats several
|
|
aspects that are important for tuning a database for optimal
|
|
performance.
|
|
</para>
|
|
|
|
<para>
|
|
The information in this part is arranged so that a novice user can
|
|
follow it start to end to gain a full understanding of the topics
|
|
without having to refer forward too many times. The chapters are
|
|
intended to be self-contained, so that advanced users can read the
|
|
chapters individually as they choose. The information in this
|
|
part is presented in a narrative fashion in topical units.
|
|
Readers looking for a complete description of a particular command
|
|
should see <xref linkend="reference">.
|
|
</para>
|
|
|
|
<para>
|
|
Readers of this part should know how to connect to a
|
|
<productname>PostgreSQL</> database and issue
|
|
<acronym>SQL</acronym> commands. Readers that are unfamiliar with
|
|
these issues are encouraged to read <xref linkend="tutorial">
|
|
first. <acronym>SQL</acronym> commands are typically entered
|
|
using the <productname>PostgreSQL</> interactive terminal
|
|
<application>psql</application>, but other programs that have
|
|
similar functionality can be used as well.
|
|
</para>
|
|
</partintro>
|
|
|
|
&syntax;
|
|
&ddl;
|
|
&dml;
|
|
&queries;
|
|
&datatype;
|
|
&func;
|
|
&typeconv;
|
|
&indices;
|
|
&textsearch;
|
|
&mvcc;
|
|
&perform;
|
|
|
|
</part>
|
|
|
|
<part id="admin">
|
|
<title>Server Administration</title>
|
|
|
|
<partintro>
|
|
<para>
|
|
This part covers topics that are of interest to a
|
|
<productname>PostgreSQL</> database administrator. This includes
|
|
installation of the software, set up and configuration of the
|
|
server, management of users and databases, and maintenance tasks.
|
|
Anyone who runs a <productname>PostgreSQL</> server, even for
|
|
personal use, but especially in production, should be familiar
|
|
with the topics covered in this part.
|
|
</para>
|
|
|
|
<para>
|
|
The information in this part is arranged approximately in the
|
|
order in which a new user should read it. But the chapters are
|
|
self-contained and can be read individually as desired. The
|
|
information in this part is presented in a narrative fashion in
|
|
topical units. Readers looking for a complete description of a
|
|
particular command should see <xref linkend="reference">.
|
|
</para>
|
|
|
|
<para>
|
|
The first few chapters are written so they can be understood
|
|
without prerequisite knowledge, so new users who need to set
|
|
up their own server can begin their exploration with this part.
|
|
The rest of this part is about tuning and management; that material
|
|
assumes that the reader is familiar with the general use of
|
|
the <productname>PostgreSQL</> database system. Readers are
|
|
encouraged to look at <xref linkend="tutorial"> and <xref
|
|
linkend="sql"> for additional information.
|
|
</para>
|
|
</partintro>
|
|
|
|
&installation;
|
|
&installw;
|
|
&runtime;
|
|
&config;
|
|
&client-auth;
|
|
&user-manag;
|
|
&manage-ag;
|
|
&charset;
|
|
&maintenance;
|
|
&backup;
|
|
&high-availability;
|
|
&recovery-config;
|
|
&monitoring;
|
|
&diskusage;
|
|
&wal;
|
|
®ress;
|
|
|
|
</part>
|
|
|
|
<part id="client-interfaces">
|
|
<title>Client Interfaces</title>
|
|
|
|
<partintro>
|
|
<para>
|
|
This part describes the client programming interfaces distributed
|
|
with <productname>PostgreSQL</>. Each of these chapters can be
|
|
read independently. Note that there are many other programming
|
|
interfaces for client programs that are distributed separately and
|
|
contain their own documentation (<xref linkend="external-projects">
|
|
lists some of the more popular ones). Readers of this part should be
|
|
familiar with using <acronym>SQL</acronym> commands to manipulate
|
|
and query the database (see <xref linkend="sql">) and of course
|
|
with the programming language that the interface uses.
|
|
</para>
|
|
</partintro>
|
|
|
|
&libpq;
|
|
&lobj;
|
|
&ecpg;
|
|
&infoschema;
|
|
|
|
</part>
|
|
|
|
<part id="server-programming">
|
|
<title>Server Programming</title>
|
|
|
|
<partintro>
|
|
<para>
|
|
This part is about extending the server functionality with
|
|
user-defined functions, data types, triggers, etc. These are
|
|
advanced topics which should probably be approached only after all
|
|
the other user documentation about <productname>PostgreSQL</> has
|
|
been understood. Later chapters in this part describe the server-side
|
|
programming languages available in the
|
|
<productname>PostgreSQL</productname> distribution as well as
|
|
general issues concerning server-side programming languages. It
|
|
is essential to read at least the earlier sections of <xref
|
|
linkend="extend"> (covering functions) before diving into the
|
|
material about server-side programming languages.
|
|
</para>
|
|
</partintro>
|
|
|
|
&extend;
|
|
&trigger;
|
|
&event-trigger;
|
|
&rules;
|
|
|
|
&xplang;
|
|
&plsql;
|
|
&pltcl;
|
|
&plperl;
|
|
&plpython;
|
|
|
|
&spi;
|
|
&bgworker;
|
|
&logicaldecoding;
|
|
&replication-origins;
|
|
|
|
</part>
|
|
|
|
&reference;
|
|
|
|
<part id="internals">
|
|
<title>Internals</title>
|
|
|
|
<partintro>
|
|
<para>
|
|
This part contains assorted information that might be of use to
|
|
<productname>PostgreSQL</> developers.
|
|
</para>
|
|
</partintro>
|
|
|
|
&arch-dev;
|
|
&catalogs;
|
|
&protocol;
|
|
&sources;
|
|
&nls;
|
|
&plhandler;
|
|
&fdwhandler;
|
|
&custom-scan;
|
|
&geqo;
|
|
&indexam;
|
|
&gist;
|
|
&spgist;
|
|
&gin;
|
|
&brin;
|
|
&storage;
|
|
&bki;
|
|
&planstats;
|
|
|
|
</part>
|
|
|
|
<part id="appendixes">
|
|
<title>Appendixes</title>
|
|
|
|
&errcodes;
|
|
&datetime;
|
|
&keywords;
|
|
&features;
|
|
&release;
|
|
&contrib;
|
|
&external-projects;
|
|
&sourcerepo;
|
|
&docguide;
|
|
&acronyms;
|
|
|
|
</part>
|
|
|
|
&biblio;
|
|
<![%include-index;[&bookindex;]]>
|
|
<![%include-xslt-index;[<index id="bookindex"></index>]]>
|
|
|
|
</book>
|