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Comment Re:Sas bandwidth constrained??? (Score 1) 158

RAID by itself does only increase the number of in-flight IOs, but it almost always comes with that most magical of pixie dust, the battery-backed cache.

The other point that I'll make is that often the only writes your RDBMS is waiting on are log writes, which are sequential anyway.

In any case - I'll cede your point that spinning rust will likely NEVER scale as well as NAND.

Comment Re:Sas bandwidth constrained??? (Score 1) 158

Yeah. The relevant metric for databases really is $/IOPS, not $/GB.

So, off the cuff, I figure you need a 700-disk array of 146GB drives to do this much storage at RAID 10 ( or 0+1 for you pedants ). That's a lot of random IO capacity. I don't know how poorly IOPS scale for systems at this magnitude, but I'd be surprised if the SSD solution was 10x IOPS over 700 15k spindles. Maybe 2-5x?

Comment Always be saving. Dont ask. (Score 2, Interesting) 404

Asking about saving is the wrong question. Saving shouldn't be a question. A document's current state should be persisted at the drop of a hat and that means undo info as well.

A small faction at MS gets this.

Android, as a platform and as recommended dev practice, gets this. Many great IPhone apps get this.

An app should expect to be terminated rudely and abruptly at any time. You'll impress the hell out of your users if you follow this rule.

Comment Re:don't use swap, doofs (Score 1) 298

...and now I find myself agreeing with pretty much everything you just said.

When performance counts, there is absolutely, positively zero substitute for understanding the workload at hand and the hardware it will run on.

Comment Re:don't use swap, doofs (Score 2, Informative) 298

In no way whatsoever did he say 'remember swap is slow; try not to use it.'

That's as wrong as the idiotic summary.

Here's a relevant quote:

A 300-GB backing store, memory mapped on a machine with no more than 16 GB of RAM, is quite typical. The user paid for 64 bits of address space, and I am not afraid to use it.

The article is about redesigning binary heaps to account for non-linear access times between nodes due to swap. This point is critical. He's NOT avoiding swap, he's planning for it.

Comment Re:other then features... (Score 2, Interesting) 213

Above and beyond SQL-92/SQL-99, PostgreSQL does a good job of implementing the non-optional parts of SQL:2003 and SQL:2008 as well, and in that regard are competitive with or better than the commercial alternatives.

PL/SQL is probably unlikely to ever be available in the Open Source PostgreSQL product, but it is a feature of EnterpriseDB, which is a PostgreSQL superset.

INSERT..ON DUPLICATE KEY UPDATE is IIRC similar to the new SQL:2003 MERGE statement, which is on the TODO list for PostgreSQL.

CLUSTER is a subset of Oracle's index-organized tables / SQL Server's clustered index features.

One of the truly innovative features that is arriving is exclusion constraints. If you've ever had to implement a scheduling system that deals with concurrent updates, you'll recognize that PostgreSQL has an absolutely killer feature that makes it trivial to solve the concurrent range-excluded searched update problem without messy application code. This feature is pure gold.

Designing a performance-intensive application that is portable across multiple databases is a frustrating, difficult task. Starting with ANSI/ISO syntax is indeed a great way to base your design, but the devil is truly in the details. ORMs can hurt as much as they help.

Comment Re:At the Risk of Sounding Like an Apologist (Score 1) 832

[...] but he sure thought up some neat ideas for a universe that John Scalzi will never come close to.

That's pretty unfair.

Scalzi may not have had the mass-market success or big screen treatment of Lucas, but turning senior citizens into killing machines is one of many 'neat' ideas. Have you actually read him?

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