diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml
index 42f01c515f9..86da84fce70 100644
--- a/doc/src/sgml/high-availability.sgml
+++ b/doc/src/sgml/high-availability.sgml
@@ -39,9 +39,9 @@
Some solutions deal with synchronization by allowing only one
server to modify the data. Servers that can modify data are
called read/write, master or primary servers.
- Servers that track changes in the master are called standby
+ Servers that track changes in the primary are called standby
or secondary servers. A standby server that cannot be connected
- to until it is promoted to a master server is called a warm
+ to until it is promoted to a primary server is called a warm
standby server, and one that can accept connections and serves read-only
queries is called a hot standby server.
@@ -165,10 +165,10 @@ protocol to make nodes agree on a serializable transactional order.
Logical replication allows a database server to send a stream of data
modifications to another server. PostgreSQL
logical replication constructs a stream of logical data modifications
- from the WAL. Logical replication allows the data changes from
- individual tables to be replicated. Logical replication doesn't require
- a particular server to be designated as a primary or a replica but allows
- data to flow in multiple directions. For more information on logical
+ from the WAL. Logical replication allows replication of data changes on
+ a per-table basis. In addition, a server that is publishing its own
+ changes can also subscribe to changes from another server, allowing data
+ to flow in multiple directions. For more information on logical
replication, see . Through the
logical decoding interface (),
third-party extensions can also provide similar functionality.
@@ -177,22 +177,24 @@ protocol to make nodes agree on a serializable transactional order.
- Trigger-Based Master-Standby Replication
+ Trigger-Based Primary-Standby Replication
- A master-standby replication setup sends all data modification
- queries to the master server. The master server asynchronously
- sends data changes to the standby server. The standby can answer
- read-only queries while the master server is running. The
- standby server is ideal for data warehouse queries.
+ A trigger-based replication setup typically funnels data modification
+ queries to a designated primary server. Operating on a per-table basis,
+ the primary server sends data changes (typically) asynchronously to the
+ standby servers. Standby servers can answer queries while the primary is
+ running, and may allow some local data changes or write activity. This
+ form of replication is often used for offloading large analytical or data
+ warehouse queries.
- Slony-I is an example of this type of replication, with per-table
- granularity, and support for multiple standby servers. Because it
- updates the standby server asynchronously (in batches), there is
- possible data loss during fail over.
+ Slony-I is an example of this type of
+ replication, with per-table granularity, and support for multiple standby
+ servers. Because it updates the standby server asynchronously (in
+ batches), there is possible data loss during fail over.
@@ -215,14 +217,10 @@ protocol to make nodes agree on a serializable transactional order.
random(), CURRENT_TIMESTAMP, and
sequences can have different values on different servers.
This is because each server operates independently, and because
- SQL queries are broadcast (and not actual modified rows). If
+ SQL queries are broadcast rather than actual data changes. If
this is unacceptable, either the middleware or the application
- must query such values from a single server and then use those
- values in write queries. Another option is to use this replication
- option with a traditional primary-standby setup, i.e., data modification
- queries are sent only to the primary and are propagated to the
- standby servers via primary-standby replication, not by the replication
- middleware. Care must also be taken that all
+ must determine such values from a single source and then use those
+ values in write queries. Care must also be taken that all
transactions either commit or abort on all servers, perhaps
using two-phase commit (
and ).
@@ -351,7 +349,7 @@ protocol to make nodes agree on a serializable transactional order.
- Allows multiple master servers
+ Allows multiple primary servers