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PostgreSQL 9.0 Released
poet writes "Today the PostgreSQL Global Development Group released PostgreSQL 9.0. This release marks a major milestone in the PostgreSQL ecosystem, with added features such as streaming replication (including DDL), Hot Standby and other nifty items like DO. The release notes list all the new features, and the guide explains them in greater detail. You can download a copy now."
Congratulations to all the Postgres developers and a big thank you from me for an amazing job! Postgres is a wonderful RDBMS and one of the best free software projects there is. Rock on!
Football Odds
LMAO... unless my sarcasm detector is malfunctioning, comparing Postgres to MySQL is extraordinarily absurd... like comparing megaliths to legos.
The Admin and the Engineer
Please tell me you're kidding. Anyone suggesting MySql for real work should just be laughed at.
Business logic never belongs in the DB. Even triggers are suspect. They can be horribly inefficient.
The fact that triggers *can* be inefficient is no reason not to use them when there's a good implementation and competent DBAs to make sure they *aren't*. Also, business logic never belongs in the DB? To the contrary- a lot of business logic is sets of rules to maintain consistency between various things. That sort of logic is *precisely* what belongs in the DB, rather than scattered throughout a variety of applications running on top of it.
The ringing of the division bell has begun... -PF
Part of the reason MySQL gets treated as a toy is its release discipline- or lack thereof. At least one of the 5.x releases came out with *known* data-loss bugs; that's just not even remotely acceptable in a database, and that's the sort of impression that's hard to shake: people aren't just going to look at subsequent releases and go "oh, well, they say they're paying more attention this time, I guess that's good enough".
The ringing of the division bell has begun... -PF
you just created a job! perhaps an entire department! great idea! well, for people that need jobs... not for people that need to pay to get something implemented correctly done for a price, or developers that take pride in the the perfection of their work and require no such additional external verification or confirmation.
I can imagine the headlines now: "Two DBA's shot each other dead yesterday morning after they fell out over the maintainability of column-based conditional triggers. A police officer at the scene remarked: 'If only they had been using MySQL with the default ISAM tables which support no such functionality, then none of this would have happened."
:D
I love the arguments in C++ and DB stories. They're so much better than watching two people slug it out over a football team in a bar.
Aide-toi, le Ciel t'aidera - Jeanne D'Arc.
The problem wasn't that the databse was used in a wrong way.
While the database platform may have been a problem, the first, biggest problem wasn't the hardware. It was (bolded for effect): business logic does not belong in your DB, excepting a handful of cases.
I wouldn't normally have replied -- I agree with your point about hardware -- but this deserves to be underscored because so many people fundamentally do not get it.
I work for a company that was just bought out. Our new parent company develops a well known (in its industry) enterprise desktop application. The entirety of their business logic is written in the DB.
It's a maintenance nightmare, difficult to integrate with outside systems, and the system does not scale. Scalability is kicking their ass... because they can't.
Our company spends much less on hardware (and software, cheers for PostgreSQL), and our application is a billion times easier to develop and maintain. We use triggers - but only a handful.
People develop middle layers for a reason. Better code organization and flow control, much, much better speed, scalability, and flexibility.
Use a DB for what it's good at (ACID, data integrity).
~Dalcius
Rome wasn't burnt in a day.
A sincere thank you for the reply.
Respectfully, I believe you're going down a bad road. For a small application, and a developer who isn't asleep at the wheel, what you're suggesting can work OK; I imagine it hasn't been a problem for you.
Generally, for everything else, it tends to blow up down the road. And even for smaller projects, the benefits of keeping your logic out of the DB (faster, cleaner, clearer, easier to learn, easier to update) are significant.
I sincerely want to make an effort to be useful to folks who may not have worked with larger projects before. Please take this post in that spirit. It's a long, and I hope informative, post.
Make your code's intent clear ... alternatively, write logic in the right context
The biggest problem is code intent and flow control. Databases model data, GUIs model user actions, but neither necessarily model business logic. You've got business logic code for that -- like your permissions handling.
Code has a logic-centric view. Databases have a data-centric view. If you write logic in the DB, you're abstracting what you're writing from what you're actually trying to accomplish.
Error handling is a great example for flow control. Trapping an error in the DB, correctly identifying the problem and bubbling it up in a user-appropriate way in a clean fashion, as you said, is difficult.
Keep your code together
Another big problem is finding all the right code. For a newbie or a dev who hasn't looked at a bit of code in 6 months, this is very important.
Breaking your code up into different buckets based on what data it modifies makes your logic - your flow - hard to follow for anyone who isn't intimately familiar with the project.
Consider two implementations for a feature:
1) Application code triggers an update to three tables. A bunch of magic spread across several triggers on those three different tables and written in (depending on your implementation) three different schema files, or one huge file with your entire schema, updates three additional tables. E.G.: "most complex updates are performed using triggers and rules"
2) One function in one file that, in a transaction, updates six tables.
Which is easier to follow? From which implementation can you get a clear vision of the intent of the code? Which is easier to skim? If a new developer looks at your code, in which implementation is he more likely to miss something the feature touches?
Don't make interoperability harder
If you push logic into your DB, interoperability becomes harder, not easier. Before, you had just data, and two different applications could use it differently and have different requirements -- as long as what they did was consistent with the data model (your schema).
Now, with logic in the DB, anyone wanting to share your data has to work around your triggers, or co-opt them, or write entirely new triggers, procedures, and generally muck up your application to accomplish their goals.
Keep your platform flexible
Pushing logic into the DB, you may have made it easier to switch languages (although you still have a bunch of "front end" code you'd have to convert/maintain), but now it is much harder to switch databases. What was once merely data is now jumbled up with your application. If Oracle, MSSQL, etc. becomes a necessity, you're not just switching databases, you'll likely be refactoring significant chunks of your app.
Most business needs won't demand you switch languages (worst case, cross-compile or use IPC). Some business needs will demand you switch databases -- my company is now porting our app to MSSQL.
Your database is likely your bottleneck
In my experience, the first serious scalability problems most apps encounter are in the database. And the solution is always "more hardware." Beefier machines.
Then comes horizontal scaling ("moar serve
~Dalcius
Rome wasn't burnt in a day.