Re: Migration to Postgres training

  • From: Mladen Gogala <gogala.mladen@xxxxxxxxx>
  • To: "Joshua D. Drake" <jd@xxxxxxxxxxxxxxxxx>, oracle-l@xxxxxxxxxxxxx
  • Date: Thu, 8 Aug 2019 16:21:35 -0400

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.


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.


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