On 06/23/2011 10:28 PM, Stephen Frost wrote:
Next, PG doesn't even use the same basic technology as Oracle regarding
how transaction isolation and versioning works. Oracle using rollback
segments to store 'old' rows in, while PG uses a Multi-Version
Concurrency Control (MVCC) system. They're fundamentally different
things, so the notion that PG is somehow a 'reverse engineered' Oracle
is complete bunk.
I stole some inspiration from this comment for my own response, which I just posted to the site. I'll save a copy here in case the author becomes so embarrassed by his mistakes he deletes it:
The idea that PostgreSQL is reverse engineered from Oracle is ridiculous. Just a look at the vast differences in the MVCC implementation of the two; Oracle's redo logs vs. PostgreSQL WAL are completely difference designs.
As for there being no unique features in PostgreSQL, that's completely wrong too. A good example is how deep the
transactional DDL features go--Oracle has started to catch up recently, but PostgreSQL still has a lead there. The ability extend the type system and indexes with your own custom items are also better in PostgreSQL than any other database. This is why the PostGIS add-on (built using the type extension facility) is busy displacing installations of the weaker Oracle Spatial at installations all over the world right now.
As for support, there are half a dozen companies in the world you can buy PostgreSQL support from at a fraction of the rate Oracle charges for it. I routinely fix bugs in the database itself within hours of report for my customers, as part of a service contract, which is an option on top of the free community support. Because PostgreSQL is open-source, there are multiple vendors available who provide this service. With Oracle as a closed source product, there can only be one who is capable of offering this quality of support. And that single source vendor has quite a history of squeezing as many dollars out of its customers as its can. Since there is choice among PostgreSQL support companies, you'll never get into that position with it.
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Greg Smith 2ndQuadrant US greg@2ndQuadrant.com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us
"PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books
