Re: moving to PostgreSQL from MS-SQL and from Oracle, looking for feature comparison information

Yuri Budilov wrote:
> My employer is evaluating PostgreSQL as a possible replacement for Oracle 11g R2 and
> MS-SQL 2008 R2 for some systems.
> I am completely new to PostgreSQL but experienced in MS-SQL and also in Oracle 11g R2.
> We need to establish what PostgreSQL is good at and not so good at - so we can decide where to use it.
> The OS will be 64-bit Linux (probably Red Hat Linux or Oracle Linux).
>
> Are there any documents comparing these products in terms of features?
> That would save me asking a lot of questions and save me weeks or months of reading of PostgreSQL manuals.

Some general remarks, since Maxim already answered your specific questions:

I am not aware if a document that compares the features, but I would like to
caution in this respect: if you come from another system, you are likely to
start searching for features that are similar to what you know from there, and
end up being disappointed if you cannot find them.
It is often not helpful to look for one-on-one feature comparison, as the same
problems are often solved in quite different ways on different systems.

One example: coming from Oracle, you might be appalled by PostgreSQL's
lack of synonyms. However, if you think the PostgreSQL way, you would view
synonyms as a band-aid for Oracle's lack of a schema search path.

Another familiar eyebrow-raiser is PostgreSQL's lack of stored procedures -
but it seems like that hasn't been a problem for practical application, a
function returning "void" usually does the trick.

Since you come from proprietary databases, I would divide the pros and cons
in two categories:

a) Features of open source software in general:
- You are empowered to analyze and fix your problems yourself, or pay
people of your choosing to do it.
- Development, design choices and decision processes happen "in the open"
and can be followed and influenced by everybody.
- You have to do more work to integrate the software with other parts of
your landscape (backup software, high availability, client software, ...).

b) PostgreSQL features:
- Excellent documentation.
- Excellent extensibility (functions in several programming languages,
packaged extensions (PGXN), user-defined types, ...).
- High code quality.
- Not owned by a single company. Hence, cannot be bought, and there is
little danger for half-baked solutions to be shipped because of customer
or marketing pressure.
- Unusually strict about correct encoding and implicit type casting.
- Excellent support on the mailing lists (you can talk to the developers, and
bugs are often fixed in a matter of days).

Since you mentioned the documentation, I'd encourage you to spend the time
to read through the manual. You will find it worth reading, particularly if
you plan to use PostgreSQL at your company.

Yours,
Laurenz Albe