Ühel kenal päeval, T, 2006-10-24 kell 00:20, kirjutas Bruce Momjian:
> Here is a new replication documentation section I want to add for 8.2:
>
> ftp://momjian.us/pub/postgresql/mypatches/replication
This is how data partitioning is currently described there
> Data Partitioning
> -----------------
>
> Data partitioning splits the database into data sets. To achieve
> replication, each data set can only be modified by one server. For
> example, data can be partitioned by offices, e.g. London and Paris.
> While London and Paris servers have all data records, only London can
> modify London records, and Paris can only modify Paris records. Such
> partitioning is usually accomplished in application code, though rules
> and triggers can help enforce partitioning and keep the read-only data
> sets current. Slony can also be used in such a setup. While Slony
> replicates only entire tables, London and Paris can be placed in
> separate tables, and inheritance can be used to access from both tables
> using a single table name.
Maybe another use of partitioning should also be mentioned. That is ,
when partitioning is used to overcome limitations of single servers
(especially IO and memory, but also CPU), and only a subset of data is
stored and processed on each server.
As an example of this type of partitioning you could mention Bizgres MPP
(a PG-based commercial product, http://www.greenplum.com ), which
partitions data to use I/O and CPU of several DB servers for processing
complex OLAP queries, and Pl_Proxy
( http://pgfoundry.org/projects/plproxy/ ) which does the same for OLTP
loads.
I think the "official" term for this kind of "replication" is
Shared-Nothing Clustering.
--
----------------
Hannu Krosing
Database Architect
Skype Technologies OÜ
Akadeemia tee 21 F, Tallinn, 12618, Estonia
Skype me: callto:hkrosing
Get Skype for free: http://www.skype.com
