Policy on PostgreSQL spin-offs

Question

greenplum and postgresql needs to be cleaned up. My suggestion is that we not permit double-tagging. postgresql should not exist on greenplum questions. The architectures are totally different,

And, from the docs:

Greenplum Database is based on PostgreSQL open-source technology. It is essentially several PostgreSQL database instances acting together as one cohesive database management system (DBMS). It is based on PostgreSQL 8.2.15, and in most cases is very similar to PostgreSQL with regard to SQL support, features, configuration options, and end-user functionality. Database users interact with Greenplum Database as they would a regular PostgreSQL DBMS.

That means that essentially we're talking about a fork that occurred so long ago, that the version from which they forked on is no longer even supported upstream. It was released on 2009-12-14. That's over seven years ago. PostgreSQL only supports 9.2+. At the very least, this should not be tagged PostgreSQL. Ideally, I would like it to not be tagged postgresql-8.2 either but because no one uses that tag, I agree the issue is somewhat moot.

This was inspired from this question which is tagged, and titled PostgreSQL however it has nothing to do with PostgreSQL. It's a Greenplum question, and it has that tag too.

The tag wiki for postgresql says the tag is supposed to be for all versions of Postgres. Simply put, Greenplum is a fork. It was never a version of PostgreSQL.

Answer 1

I agree — a greenplum question shouldn't also be tagged postgres.

From the Greenplum website:

Originally based on PostgreSQL

Apart from that there is hardly a mention, and I assume it will diverge more and more over time.

Also, from Wikipedia:

The primary competitors for Pivotal Greenplum Database, are the other MPP database systems provided by major industry vendors such as Teradata, Amazon Redshift, Azure Data Warehouse and IBM Netezza. Additional competition comes from other smaller competitors, column-oriented databases such as HP Vertica and data warehousing vendors with, non MPP architecture, such as Oracle Exadata, IBM DB2, and Hadoop distributions such as Cloudera and Hortonworks.

So it's not really likely that there'll be a huge crossover of Postgres experts interested in Greenplum questions.

Answer 2

In my experience, greenplum is similar enough to postgresql that many questions will have answers that are equally applicable to both.

Yes, there is a risk that someone might ask a question whose answer hangs on a significant difference, and I have done that - posted a question that I did not know was Greenplum specific - and yes, that might have wasted the attention of someone who only knows PostgreSQL. Hopefully, though, such questions might be interesting to people who don't use Greenplum, I am always interested to learn things about database platforms that I am not currently using.

As long as people are encouraged to tag a question as PostgreSQL only if they believe that the question is equally relevant to either, then I believe that this policy should be advisory only. PostgreSQL tags certainly should be removed if it becomes apparent that the solution is only related either to Greenplum or the very old PostgreSQL base on which it is built.