20bits - Latest Comments in General

Re: Facebook Users Are Fans of Entertainment

Nick O'Neill — Tue, 20 May 2008 03:17:07 -0000

Hey Jesse,

I'm writing a post on this now ... should be up by morning

Re: Facebook Users Are Fans of Entertainment

jfarmer — Tue, 20 May 2008 02:01:19 -0000

Thanks! Send it to your friends. :)

Re: Facebook Users Are Fans of Entertainment

daveambrose — Tue, 20 May 2008 01:10:10 -0000

Fantastic.

Re: Facebook Bans Google Friend Connect

jfarmer — Fri, 16 May 2008 16:57:05 -0000

John,

I actually agree, in part. Facebook is trying their hardest to hold
onto the monolith they've constructed. That's certainly something
they have that Google doesn't.

But you're right in that they think they have more control than they
do. The Microsoft-style lock-in isn't there yet and Facebook has
given away its hand. They can't even emulate Microsoft correctly
— you stay open until everyone is using your platform and then
cripple everyone else.

Part of it is that these old strategies just aren't as feasible as
they once were. On the network people move too fast to lock them
down.

The tighter the grip the quicker their users will slip through their fingers.

Re: Facebook Bans Google Friend Connect

John Furrier — Fri, 16 May 2008 16:24:43 -0000

You have the right read on the 'press their competitive advantage" - but i'd submit to you that they don't have that yet. In fact Facebook came across like Netscape not Microsoft. Facebook thinks they have sustainability in their platform - not yet. It's a false sense of security on their part. They aren't at the Microsoft levels of leverage yet. In their mind they are but not in competitive strategy.

It's Google who has the leverage not Facebook.

Here's my post

http://furrier.org/2008/05/15/facebook-just-pul...

Re: Interview Questions: Two Bowling Balls

rouli — Thu, 15 May 2008 13:48:27 -0000

Actually it can be proven that 14 is the best (integer) you can get. Proving this can be another interview question :)

Re: Interview Questions: Database Indexes

Jacque Confortis — Thu, 15 May 2008 06:00:19 -0000

Perhaps the most important attribute of a B-Tree is that it is a balanced data structure. This is the primary reason that O(log n) operations exist for insert, delete, and search.

Re: Interview Questions: Database Indexes

Neil — Wed, 14 May 2008 18:59:24 -0000

Another important point to mention is when indexes are NOT a good idea. You shouldn't just blindly add indexes for any fields mentioned in a query's WHERE clause. Aside from the insert/update cost and disk space consumption, the optimizer may rightly decide not to use the index in the first place if the fraction of the rows in the table that are satisfied by the WHERE clause is relatively high (say, 5% or more of all the rows in the table). This is because scanning an index requires extra I/O, and random I/O at that.

Another interesting interview question is "how would you build a system that can use multiple indexes on a *single* table to answer a single query"? (That is, given WHERE a = k1 OR b = k2, how do you make use of indexes on both a and b?)

Re: Interview Questions: Database Indexes

jfarmer — Wed, 14 May 2008 14:27:45 -0000

Glad to hear it! Are you interested in just more database-related articles or something more general?

Re: Interview Questions: Database Indexes

Bryan Migliorisi — Wed, 14 May 2008 14:10:49 -0000

I am a developer who is learning MySQL (and general DBA type stuff) and this was great! I hope you continue to pump out this kinda stuff. I am adding you to my Google Reader.

Re: Interview Questions: Database Indexes

jfarmer — Tue, 13 May 2008 23:33:38 -0000

Yeah, he wanted you to talk about B-trees, hashes, bitmaps, R-trees, etc. I would've just asked him to clarify. Circumspect interview questions are stupid — ask what you want to know.

Re: Interview Questions: Database Indexes

Hung — Tue, 13 May 2008 22:20:01 -0000

I've been asked this in a phone interview before. Went through the whole "makes your queries faster but there's slows down inserts and deletes" stuff fine. But then the interviewer started asking about "types" of indexes. I replied I just knew about the indexing type, and perhaps the "unique" index type of mysql. I can't really figure out if he was trying to get me to talk about the other type (primary key) or the actual methods of indexing (b-tree vs hashing). It didn't seem too essential to the position I was interviewing for anyway.

Re: Interview Questions: Database Indexes

jfarmer — Tue, 13 May 2008 21:54:59 -0000

Testing DIsqus comments. Let's see if it works!

Re: Interview Questions: Database Indexes

jfarmer — Tue, 13 May 2008 01:04:05 -0000

Moo moo moo

Re: Interview Questions: Database Indexes

jfarmer — Tue, 13 May 2008 01:03:46 -0000

Test