What Is New In PostgreSQL 9.0

Jamie noted a blog that says "PostgreSQL 9.0 beta 2 just got released this week. We may see another beta before 9.0 is finally released, but it looks like PostgreSQL 9.0 will be here probably sometime this month. Robert Treat has a great slide presentation showcasing all the new features."

Comments

Built-in replication

[atomic777]

A better summary of the changes is here.

After years of resisting, one of the more significant changes is the inclusion of WAL shipping-based replication into postgresql core, and the ability to do read-only queries on the standby systems. This will hopefully go a long way towards appeasing mysql users used to the "easy" replication that mysql provides.

Re:Built-in replication

[BSAtHome]

And streaming replication. It makes it a lot easier to have a backup server that is up to date. It makes me happy so I can do partial restores without a lot of fuss.
Now, if only the enterprise apps could find out to reconnect to the database and continue where they left off without crashing and trashing.

Color me skeptical.

[Estanislao Mart�nez]

This bites me occasionally in Oracle where you've got a big query that has lots of tables joined together, and then at some point one of the columns is removed from the select part, and the query performance suddenly goes to hell. Then you have to go through and verify that each table is actually being used (even worse if the column that was removed from the select came from deep joins).

Do you have an actual example? I simply don't see how removing a column from a select clause would make a query slower, unless you're talking about uses of aggregate functions, and even there I'm having a hard time seeing how a removal could make things worse.

The thing that determines how much work the database has to do in order to produce the results is the FROM, the WHERE and the GROUP BY, because those are the ones that determine what's going to be accessed, joined, sorted and how. The SELECT (except for the use of aggregate functions) primarily just decides what information to present from the join results and how to present it.