pgpool2.git / summary / log / commit / refs
commit ecd4b04a4e7664c04675bd22b7e02c79d02d3611
Author: Tatsuo Ishii <ishii@sraoss.co.jp>
Date: Mon Feb 01 10:25:24 2021 +0000
Rewrite introduction to Pgpool-II.
Change the meaning of "pool" and make it clear that what are the
essential features of Pgpool-II.
doc.ja/src/sgml/intro.sgml | 149 +++++++++++++++++++++++----------------------
doc/src/sgml/intro.sgml | 121 ++++++++++++++++++------------------
2 files changed, 137 insertions(+), 133 deletions(-)
diff --git a/doc.ja/src/sgml/intro.sgml b/doc.ja/src/sgml/intro.sgml
index 41dadb491..fe713d859 100644
--- a/doc.ja/src/sgml/intro.sgml
+++ b/doc.ja/src/sgml/intro.sgml
@@ -107,78 +107,106 @@
<para>
<!--
- <productname>Pgpool-II</productname> is a proxy software that sits
- between <productname>PostgreSQL</productname> servers and a
- <productname>PostgreSQL</productname> database client. It provides
- the following features:
+ <productname>Pgpool-II</productname> manages a
+ <firstterm>pool</firstterm> of
+ <productname>PostgreSQL</productname> servers to achieve some
+ features that are not available with single
+ <productname>PostgreSQL</productname> installation. The fearures
+ include:
-->
- <productname>Pgpool-II</productname>は、<productname>PostgreSQL</productname>サーバと<productname>PostgreSQL</productname>データベースクライアントの間に位置するプロキシソフトウェアです。
- 以下のような機能を提供します。
+ <productname>Pgpool-II</productname>は<productname>PostgreSQL</productname>の<firstterm>pool</firstterm>を管理することによって、単一の<productname>PostgreSQL</productname>構成では得られない以下のような機能を提供します。
<variablelist>
<varlistentry>
- <!--
- <term>Connection Pooling</term>
- -->
- <term>コネクションプーリング</term>
+<!--
+ <term>High Availability</term>
+-->
+ <term>高可用性</term>
<listitem>
<para>
- <!--
- <productname>Pgpool-II</productname> maintains established
- connections to the <productname>PostgreSQL</productname>
- servers, and reuses them whenever a new connection with the
- same properties (i.e. user name, database, protocol version, and other connection parameters if any)
- comes in. It reduces the connection overhead, and improves
- system's overall throughput.
- -->
- <productname>Pgpool-II</productname>は、<productname>PostgreSQL</productname>サーバへの確立された接続を維持し、プロパティ（つまりユーザ名、データベース、プロトコルバージョン、他に指定されていれば接続パラメータも）が同じ新規のコネクションが到着する度に再利用します。
- コネクションオーバヘッドを軽減することによって、システム全体のスループットを改善します。
+<!--
+ <productname>Pgpool-II</productname> provides a high
+ availability (HA) feature by using multiple
+ <productname>PostgreSQL</productname> servers so that it
+ automatically removes broken server from the server pool to
+ continue the database task. This is called <firstterm>automatic
+ failover</firstterm>. Also <productname>Pgpool-II</productname>
+ offers an HA feature for <productname>Pgpool-II</productname>
+ itself, called <firstterm>Watchdog</firstterm> (see <xref
+ linkend="tutorial-watchdog"> for more details). Moreover
+ <productname>Pgpool-II</productname> hires sophoiscated
+ <firstterm>quorum</firstterm> algorithm to aovid false positive
+ errors and split brain problem to make the whole HA system
+ highly reliable. See <xref
+ linkend="config-watchdog-failover-behavior"> for more details.
+-->
+ <productname>Pgpool-II</productname>は複数の<productname>PostgreSQL</productname>サーバを使い、故障したサーバを自動的に取り除くことによってデータベースの仕事を継続して高可用性 (HA)機能を提供します。
+ これは<firstterm>自動フェイルオーバ</firstterm>と呼ばれます。
+ また、<productname>Pgpool-II</productname>は<productname>Pgpool-II</productname>自身のHA機能を提供しており、これを<firstterm>Watchdog</firstterm>と呼びます (詳細は<xref linkend="tutorial-watchdog">をご覧ください。)
+ 更に<productname>Pgpool-II</productname>は洗練された<firstterm>クォーラム(quorum)</firstterm>アルゴリズムを採用しており、偽陽性エラーとスプリットブレイン問題を回避することが可能で、HAシステム全体が非常に信頼性の高いものになっています。
+ 詳細は<xref linkend="config-watchdog-failover-behavior">をご覧ください。
</para>
</listitem>
</varlistentry>
<varlistentry>
- <!--
- <term>Load Balancing</term>
- -->
+<!--
+ <term>Load balancing</term>
+-->
<term>負荷分散</term>
<listitem>
<para>
- <!--
- If a database is replicated (because running in either
- replication mode or native replication mode), performing a SELECT
- query on any server will return the same result. <productname>Pgpool-II</productname>
- takes advantage of the replication feature in order to reduce
- the load on each PostgreSQL server. It does that by
- distributing SELECT queries among available servers, improving
- the system's overall throughput. In an ideal scenario, read
- performance could improve proportionally to the number of
- PostgreSQL servers. Load balancing works best in a scenario
- where there are a lot of users executing many read-only
- queries at the same time.
- -->
- （レプリケーションモードあるいはマスタースレーブモードで動作しているので）データベースがレプリケーションされている場合は、どのサーバにSELECTを発行しても同じ結果が得られます。
- <productname>Pgpool-II</productname>は、個々のPostgreSQLサーバの負荷を軽減するために、レプリケーションを利用します。
- SELECTクエリをサーバに分散させ、システム全体のスループットを改善します。
- 理想的には、PostgreSQLサーバの数に比例して検索性能が向上します。
- 多数のユーザが検索のみのクエリを同時に発行するようなシナリオで、負荷分散は最大の効果を発揮します。
+<!--
+ <productname>Pgpool-II</productname> distributes read queries
+ over multiple <productname>PostgreSQL</productname> servers to
+ gain higher performance. This feature is called <firstterm>load
+ balancing</firstterm>. Write queries are sent to either the
+ primary server (in streaming replication mode) or all servers
+ (in native replication mode and snapshot isolation mode). See
+ <xref linkend="running-mode"> for more details about these
+ mode. In any case, <productname>Pgpool-II</productname>
+ automatically distinguish the read queries from the write
+ queries.
+-->
+ <productname>Pgpool-II</productname>は読み込みクエリを複数の<productname>PostgreSQL</productname>サーバに分散させて性能向上させることがで
+きます。
+ これは<firstterm>負荷分散</firstterm>と呼ばれます。書き込みクエリはプライマリサーバ(ストリーミングレプリケーションモード時)かすべてのサーバ(ネィティブレプリケーションモードあるいはスナップショットアイソレーションモード）に送られます。
+ これらのモードの詳細は<xref linkend="running-mode">をご覧ください。
+ どの場合でも、<productname>Pgpool-II</productname>は自動的に読み込みクエリと書き込みクエリの違いを判断します。
</para>
</listitem>
</varlistentry>
+ </variablelist>
+ </para>
+ <para>
+<!--
+ Besides these essential features, Pgpool-II also provides useful
+ features such as:
+-->
+ これらの基本的な機能以外に、<productname>Pgpool-II</productname>は以下の機能を提供します。
+ </para>
+ <para>
+ <variablelist>
<varlistentry>
- <term>自動フェイルオーバ</term>
+
+ <!--
+ <term>Connection Pooling</term>
+ -->
+ <term>コネクションプーリング</term>
<listitem>
<para>
<!--
- If one of database servers goes down or becomes unrechable,
- <productname>Pgpool-II</productname> will detaches it and continues operations using rest
- of database servers. There are some sophiscated features which
- help the automated fail over including timeout and retries.
+ <productname>Pgpool-II</productname> maintains established
+ connections to the <productname>PostgreSQL</productname>
+ servers, and reuses them whenever a new connection with the
+ same properties (i.e. user name, database, protocol version, and other connection parameters if any)
+ comes in. It reduces the connection overhead, and improves
+ system's overall throughput.
-->
- データベースサーバのどれかがダウンしたり、到達できなくなったときは、<productname>Pgpool-II</productname>はそのサーバを切り離し、残ったサーバで運用を継続します。
- 自動フェイルオーバの助けになるような、タイムアウト、リトライといった洗練された機能もあります。
+ <productname>Pgpool-II</productname>は、<productname>PostgreSQL</productname>サーバへの確立された接続を維持し、プロパティ（つまりユーザ名、データベース、プロトコルバージョン、他に指定されていれば接続パラメータも）が同じ新規のコネクションが到着する度に再利用します。
+ コネクションオーバヘッドを軽減することによって、システム全体のスループットを改善します。
</para>
</listitem>
</varlistentry>
@@ -204,31 +232,6 @@
</listitem>
</varlistentry>
- <varlistentry>
- <term>レプリケーション</term>
- <listitem>
- <para>
- <!--
- <productname>Pgpool-II</productname> can manage
- multiple <productname>PostgreSQL</productname>
- servers. Activating the replication feature makes it possible
- to create a real time backup on 2 or
- more <productname>PostgreSQL</productname> clusters, so that
- the service can continue without interruption if one of those
- clusters fails. <productname>Pgpool-II</productname> has
- built-in replication (native replication). However user can
- use external replication features including streaming
- replication of <productname>PostgreSQL</productname>.
- -->
- <productname>Pgpool-II</productname>は複数の<productname>PostgreSQL</productname>サーバを管理することができます。
- レプリケーション機能を有効にすることにより、2つあるいはそれ以上の<productname>PostgreSQL</productname>クラスタのリアルタイムバックアップを作成できます。
- これによって、クラスタの一つがダウンしても、中断なしにサービスを継続できます。
- <productname>Pgpool-II</productname>には、組み込みレプリケーション（ネィティブレプリケーション）機能があります。
- しかし、<productname>PostgreSQL</productname>のストリーミングレプリケーションのような、外部のレプリケーション機能を使うこともできます。
- </para>
- </listitem>
- </varlistentry>
-
<varlistentry>
<term>限度を超えた接続の制限</term>
<listitem>
diff --git a/doc/src/sgml/intro.sgml b/doc/src/sgml/intro.sgml
index c0a8c6f05..d9e786722 100644
--- a/doc/src/sgml/intro.sgml
+++ b/doc/src/sgml/intro.sgml
@@ -74,54 +74,73 @@
<title> What is <productname>Pgpool-II</productname>?</title>
<para>
- <productname>Pgpool-II</productname> is a proxy software that sits
- between <productname>PostgreSQL</productname> servers and a
- <productname>PostgreSQL</productname> database client. It provides
- the following features:
+ <productname>Pgpool-II</productname> manages a
+ <firstterm>pool</firstterm> of
+ <productname>PostgreSQL</productname> servers to achieve some
+ features that are not available with single
+ <productname>PostgreSQL</productname> installation. The fearures
+ include:
<variablelist>
<varlistentry>
- <term>Connection Pooling</term>
+ <term>High Availability</term>
<listitem>
<para>
- <productname>Pgpool-II</productname> maintains established
- connections to the <productname>PostgreSQL</productname>
- servers, and reuses them whenever a new connection with the
- same properties (i.e. user name, database, protocol version, and other connection parameters if any)
- comes in. It reduces the connection overhead, and improves
- system's overall throughput.
+ <productname>Pgpool-II</productname> provides a high
+ availability (HA) feature by using multiple
+ <productname>PostgreSQL</productname> servers so that it
+ automatically removes broken server from the server pool to
+ continue the database task. This is called <firstterm>automatic
+ failover</firstterm>. Also <productname>Pgpool-II</productname>
+ offers an HA feature for <productname>Pgpool-II</productname>
+ itself, called <firstterm>Watchdog</firstterm> (see <xref
+ linkend="tutorial-watchdog"> for more details). Moreover
+ <productname>Pgpool-II</productname> hires sophoiscated
+ <firstterm>quorum</firstterm> algorithm to aovid false positive
+ errors and split brain problem to make the whole HA system
+ highly reliable. See <xref
+ linkend="config-watchdog-failover-behavior"> for more details.
</para>
</listitem>
</varlistentry>
<varlistentry>
- <term>Load Balancing</term>
+ <term>Load balancing</term>
<listitem>
<para>
- If a database is replicated (because running in either
- replication mode or native replication mode), performing a SELECT
- query on any server will return the same result. <productname>Pgpool-II</productname>
- takes advantage of the replication feature in order to reduce
- the load on each PostgreSQL server. It does that by
- distributing SELECT queries among available servers, improving
- the system's overall throughput. In an ideal scenario, read
- performance could improve proportionally to the number of
- PostgreSQL servers. Load balancing works best in a scenario
- where there are a lot of users executing many read-only
- queries at the same time.
+ <productname>Pgpool-II</productname> distributes read queries
+ over multiple <productname>PostgreSQL</productname> servers to
+ gain higher performance. This feature is called <firstterm>load
+ balancing</firstterm>. Write queries are sent to either the
+ primary server (in streaming replication mode) or all servers
+ (in native replication mode and snapshot isolation mode). See
+ <xref linkend="running-mode"> for more details about these
+ mode. In any case, <productname>Pgpool-II</productname>
+ automatically distinguish the read queries from the write
+ queries.
</para>
</listitem>
</varlistentry>
+ </variablelist>
+ </para>
+ <para>
+ Besides these essential features, <productname>Pgpool-II</productname> also provides useful
+ features such as:
+ </para>
+ <para>
+ <variablelist>
<varlistentry>
- <term>Automated fail over</term>
+ <term>Connection Pooling</term>
<listitem>
<para>
- If one of the database servers goes down or becomes unreachable,
- <productname>Pgpool-II</productname> will detach it and will continue operations by using the rest
- of database servers. There are some sophisticated features that
- help the automated failover including timeouts and retries.
+ <productname>Pgpool-II</productname> maintains established
+ connections to the <productname>PostgreSQL</productname>
+ servers, and reuses them whenever a new connection with the
+ same properties (i.e. user name, database, protocol version, and other connection parameters if any)
+ comes in. It reduces the connection overhead, and improves
+ system's overall throughput.
</para>
</listitem>
</varlistentry>
@@ -139,24 +158,6 @@
</listitem>
</varlistentry>
- <varlistentry>
- <term>Replication</term>
- <listitem>
- <para>
- <productname>Pgpool-II</productname> can manage
- multiple <productname>PostgreSQL</productname>
- servers. Activating the replication feature makes it possible
- to create a real time backup on 2 or
- more <productname>PostgreSQL</productname> clusters, so that
- the service can continue without interruption if one of those
- clusters fails. <productname>Pgpool-II</productname> has
- built-in replication (native replication). However user can
- use external replication features including streaming
- replication of <productname>PostgreSQL</productname>.
- </para>
- </listitem>
- </varlistentry>
-
<varlistentry>
<term>Limiting Exceeding Connections</term>
<listitem>
@@ -222,21 +223,21 @@
</para>
<para>
- <productname>Pgpool-II</productname> works on Linux, Solaris,
- FreeBSD, and most of the UNIX-like architectures. Windows is not
+ <productname>Pgpool-II</productname> works on Linux, FreeBSD, and
+ most of the UNIX-like architectures. Windows is not
supported. Supported PostgreSQL server's versions are 7.4 and
- higher. You must also make
- sure that all of your <productname>PostgreSQL</productname>
- servers are using the same major version. In addition to this, we
- do not recommend mixing
- different <productname>PostgreSQL</productname> installation with
- different build options: including supporting SSL or not, to use
- --disable-integer-datetimes or not, different block size. These
- might affect part of functionality
- of <productname>Pgpool-II</productname>. The difference of
- <productname>PostgreSQL</productname> minor versions is not
- usually a problem. However we do not test every occurrence of
- minor versions and we recommend to use exact same minor version of
+ higher (some of the features may not work with older versions of
+ <productname>PostgreSQL</productname>). You must also make sure
+ that all of your <productname>PostgreSQL</productname> servers are
+ using the same major version. In addition to this, we do not
+ recommend mixing different <productname>PostgreSQL</productname>
+ installation with different build options: including supporting SSL
+ or not, to use --disable-integer-datetimes or not, different block
+ size. These might affect part of functionality of
+ <productname>Pgpool-II</productname>. The difference of
+ <productname>PostgreSQL</productname> minor versions is not usually
+ a problem. However we do not test every occurrence of minor
+ versions and we recommend to use exact same minor version of
<productname>PostgreSQL</productname>.
</para>
[parent: e46546b26bb6]