On 23 April 2014 23:30, Josh Berkus <josh@agliodbs.com> wrote:
> Well, the question is, can we do anything practically useful with CE/LD
> as it is in 9.4 right now?
Yes, you can. An accurate, complete and usable mechanism for
extracting changesets that is likely to be used in many interesting
ways for integrating PostgreSQL into larger solutions and enterprises.
> If no, the we hold off until we have the
> complete set of stuff. If so, we announce it now, and announce the
> additional features in 9.4/10.0.
Define "complete set of stuff".
Hopefully the more obvious logical replication facilities will be in
core by 9.5, but there are many possible features associated with
these technologies and many of those will never be in core because
they relate to integration with other software, much of it with
incompatible licencing.
Having an API that enables out-of-core solutions is more powerful and
useful to PostgreSQL users than having it in-core. It would be a
mistake to regard what we have as incomplete. We can expect rapid
development of solutions around this.
This is different to Mat Views because the initial implementation of
that lacked an important aspect of usability (in that it exclusively
locked the mat view while it was refreshed, making it unusable in
production for highly available systems). No doubt we will discover
some useful additional features of CE/LD, but the main parts are very
usable and performant.
So my description for advocacy of CE/LD is
* Changeset Extraction API - high performance mechanism for reading a
stream of changes from the database, enabling integration with other
software servers. This is the core technology that will be built on in
later releases to add Online Upgrades, Logical Replication and
eventually Sharded and Massively Parallel systems. Downstream
developers are invited to use the new API to enable deep integration
of PostgreSQL into complex/enterprise data processing environments.
This important new technology solidifies PostgreSQL role as database
of choice for front line production systems that can feed data
efficiently throughout the enterprise.
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services