Re: Migration to Postgres training

From: Mladen Gogala <>
Date: Thu, 8 Aug 2019 16:21:35 -0400
Message-ID: <>

On 8/8/19 2:44 PM, Joshua D. Drake wrote:
> If you are looking for a single in box solution to solve all your
> needs, it is true that Postgres won't necessarily service your needs.
> However, to address the two specific points:
> No "in-memory": PostgreSQL has unlogged tables. It also works
> wonderfully with any number of in-memory solutions such as redis or
> memcache

It's not the same: the in-memory solution developed by IBM and Oracle maintains both the classic block/row storage and columnar storage in memory. So called in-memory technique is not just a bigger cache, it's a data warehouse technology. Unlogged tables or memcached are simply buffering techniques.

> Partitioning: This gets better every release. Version 10 was o.k., 11
> was much better, and 12 is even better. Pretty much the only thing
> missing as of 12 is the global indexes. However, you can have Primary
> Keys per partition with 12.

I'll have to check it up. I have played with Pg11 but not with Pg12. However, the lack of global indexes is a crucial feature.

> It all depends on your specific needs but PostgreSQL can usually
> service 100% of 95% of Oracle users needs.
> JD

That's a very brave statement. How did you come up with those numbers? Does PgSQL have its own version of TDE? How about fine-grained auditing? Do you have a tool like EM Express built into the database? How do compare your backups to rman backups?

Don't get me wrong, Postgres is a nice OSS database but is not as feature rich as Oracle. Not even remotely so. I have been doing projects where people expressed the desire to get off  Oracle and start using something else. Postgres was in play with 2 companies, but I've had the most of success with DB2 which can match Oracle on feature by feature basis and is significantly cheaper. I like Postgres, but so called migration projects should be done vewy, vewy cawefully.

Received on Thu Aug 08 2019 - 22:21:35 CEST

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