DB2 vs PostgreSQL vs SQL Server
Has anyone used all three of these databases? What are your experiences with them? PostgreSQL looks pretty tempting for a project but I'm curious to learn more about it (We're a .NET Shop). I've also heard of quite a lot of people being satisfied with DB2.
Answer
I work in a very large organization that uses DB2 primarily on Linux (Red Hat). We have a number of large databases and have investigated moving to other RDBMS solutions, such as Oracle and SQL Server. I did a lot of work on the SQL server end of that.
We found that SQL server performs much better and requires less tuning than DB2, especially when tables frow larger than 1M records. HADR is also difficult and bulky, to say the least.
We found many differences between DB2 and SQL Server, and too many to list here. I was responsible for doing a lot of the engineering behind code conversion from one platform to another, and can't say I found anything in DB2 to be superior to SQL server, but did find many things I liked better about SQL server. Here are some off the top of my head:
- Better selection data types in SQL Server, such as MONEY and SMALL MONEY.
- Mixed character encoding in SQL Server. Some columns can be ANSI and others UNICODE (char and nchar, respectively). Setting this up in DB2 is neither straightforward nor easy.
- Better tools in SQL server, mainly SSIS for ETL (As opposed to the insanely priced IBM Data Stage).
- SQL server has more forgiving syntax. For example, you don't need semi-colons everywhere. Maybe just a personal preference but I found it much easier to code in T-SQL.
- Many advanced features seem to work better in SQL server. For example, SQL server lets you do page-level compression, where DB2 is limited to row-level compression.
- It was easier to tune SQL Server queries with the SQL Server IDE
There are more, but honestly I suggest that anyone who is considering one over the other should set both up and spend some time working with both systems. Right now it seems like SQL server is a better overall solution, but DB2 may one day take the crown.
Lastly, when dealing with data warehousing, SQL, SSIS, and SSAS made a much better solution than InfoSphere, DataStage, and DB2. I could write a whitepaper on it, but my suggestion here is to set it up on your own and spend a week or to playing with each solution. Microsoft's solution here was faster and cheaper than IBM's. I don't know of any other basis upon which to make a decision.
Platform shouldn't be an issue since databases generally run on their own machines, but there are always those "no microsoft!" and "no linux!" shops around. It's a shame, really. I'd recommend SQL server.