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| author | Bruce Momjian <bruce@momjian.us> | 2019-10-07 18:06:08 -0400 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2019-10-07 18:06:08 -0400 |
| commit | 47eec34e4674e327ba7c2c57dda19241c889859e (patch) | |
| tree | 2610a8970d017a214bf5a7361ccaabd6f59fc32c /doc/src | |
| parent | cae078f3f98fa3614b12719d276db376df95d473 (diff) | |
| download | postgresql-47eec34e4674e327ba7c2c57dda19241c889859e.tar.gz postgresql-47eec34e4674e327ba7c2c57dda19241c889859e.zip | |
docs: Improve A?synchronous Multimaster Replication descr.
The docs for sync and async multimaster replication were unclear about
when to use it, and when it has benefits; this change clarifies that.
Reported-by: juha-pekka.eloranta@reaktor.fi
Discussion: https://postgr.es/m/156856543824.1274.12180817186798859836@wrigleys.postgresql.org
Backpatch-through: 9.4
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/high-availability.sgml | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index 43bcb2a6efd..a42541f4200 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -237,7 +237,8 @@ protocol to make nodes agree on a serializable transactional order. <listitem> <para> - For servers that are not regularly connected, like laptops or + For servers that are not regularly connected or have slow + communication links, like laptops or remote servers, keeping data consistent among servers is a challenge. Using asynchronous multimaster replication, each server works independently, and periodically communicates with @@ -256,9 +257,8 @@ protocol to make nodes agree on a serializable transactional order. In synchronous multimaster replication, each server can accept write requests, and modified data is transmitted from the original server to every other server before each transaction - commits. Heavy write activity can cause excessive locking, - leading to poor performance. In fact, write performance is - often worse than that of a single server. Read requests can + commits. Heavy write activity can cause excessive locking and + commit delays, leading to poor performance. Read requests can be sent to any server. Some implementations use shared disk to reduce the communication overhead. Synchronous multimaster replication is best for mostly read workloads, though its big |