Dumpin' my brain

SQL server performance tuning - Avoid In statement

2012-02-24T18:22:00.001-08:00

I fixed a slow nested query by replacing an IN statement with a join with a temp table. I believe this trick really works when the inner query is

Before:
Select * From Table1
Where FKID IN (Select ID From Table2 Where...)

After:
Declare @Temp TABLE(ID int)
Insert Into @Temp
Select ID From Table2 Where...

Select *

From Table1 Inner Join @Temp tmp

On Table1.FKID = tmp.ID

Dwolla fees are even lower

2011-12-01T07:43:00.000-08:00

All transactions under $10 are now free. +1 for small business:
http://blog.dwolla.com/all-transactions-under-10-are-now-free-1-for-small-business/

Major changes to the registration process - Dwolla

2011-11-10T17:05:00.000-08:00

Dwolla enhanced registration including better Facebook integration:
Major changes to the registration process - Dwolla

'via Blog this'

Dwolla

2011-10-24T19:00:00.000-07:00

I was really excited when I found out about Dwolla payment service. It offers not only a PayPal like payment gateway for websites, but also a very creative payment option for "offline" merchants in physical stores. The fees are really low compared to any other payment service and the idea that you pay absolutely nothing when you transfer money back and forth from your bank account is just great. Dwolla Spots application on the web or your mobile phone shows you information about nearby merchants.

On the downside, the service works only inside the US. This is something I hope I see changed in the near future. Dwolla does not support credit card payment from and to your online account. That's the whole idea behind Dwolla: skip the "plastic" to reduce costs. You have to transfer funds directly from your bank account.

In general I think Dwolla is great for small to medium businesses. They will be able to save a lot of transaction fees they pay to other payment services. I think it's also ideal to consider using Dwolla for a site accepting donations.

Surely You're Joking, Mr. Feynman!

2011-09-17T09:38:00.000-07:00

I bought this book from Amazon.com for $9.9 a couple of months ago. I'm reading it
slowly since then and it's a really funny book. That guy was really crazy, he tells you stories about working with Einstein in project Manhattan and then how he learnt to flirt with girls in night clubs after making it till college as a shy guy.

A couple of stories gave me the impression he's a bit tough on the emotional side, but that didn't make it any less amusing. I also got the feeling that life back then (40's to 60's) was a lot easier than today. He seemed to have a lot of time to work, play, get married a few times and write down about all that.

I'm not trying to spoil your reading so I'm not gonna say anymore. Surely, I will look for other books for Mr. Feynman in the future.

LEGO

2011-06-12T19:35:00.000-07:00

I haven't played with Lego for years now, and back then I was too young to play with LEGO Technic. Last week, I suddenly couldn't resist buying this one (and it was cheap enough). It has two models included: a Jeep and a "buggy". Second options naturally appeal to me, so I picked the buggy. Building it was completed in like 2 hours, I thought it will be bigger and take more time but not bad for my come back.

And here's the buggy:

In Hartford Connecticut

2011-06-08T20:21:00.000-07:00

I've been in Hartford, CT for a week now, and the first storm blew tonight. Not really a strong one, nothing we don't see back in Egypt. I'm just not used to rain in the summer. Today was also the hottest day this week with temperature reaching 35c.

Update Sep 17th: I wrote this post too soon and never had time to update it. Of course, since then I've seen a lot of weather I never saw before, not to mention hurricane Irene.

Virta Pay Digital Delivery

2011-05-18T16:00:00.000-07:00

Finally, after a long wait, VirtaPay kicked off Digital Delivery project on May 15th. The launch was delayed more than once, but it is good to see it actually working. The project added ability for all registered users to buy and sell digital goods.

I got really mixed up when I was looking for items to test how to buy something. First I was disappointed to find most items for sale are either fake or pirated. Only a couple of hours later, I could see the rating system is working and genuine items are moving closer to the top.

With time, flaws in the process seem to be discovered. The most obvious in my opinion is that after an item gets rated 50 times, it becomes immune to becoming flagged as inappropriate. This is called an "Established Item". Today, VirtaPay announced that many items were removed, but the flagging process is not changed.

Regardless to all that, I find it quite amusing to watch a new born currency and see its value changing with time. I haven't played with Warcraft or Second Life currencies before, so this is all new to me. We'll see what the good old "demand and supply" has to say.

Cluster spot price in Amazon EC2

2011-05-13T16:56:00.000-07:00

Spot pricing is a feature in Amazon EC2 cloud that enables users to bid for machines at prices usually lower than the tag price. Prices change quickly over time and several sites keep track of these changes. Till last month, the powerful cluster instances were not available for spot pricing. This includes cluster CPU instance (cc1.4xlarge) and cluster GPU instance (cg1.4xlarge).

On April 7th, Amazon made the cluster instances available for spot pricing on the US east region. Using spot pricing for these instances roughly saves 65% of cost compared to on demand price (CPU instance at $1.6/hour and GPU instance at $2.1/hour).

I could not find price history for the new instances maintained in any of the sites above, so I created a simple chart to do that. The chart displays instance price at different points in time and also the average of the price.

All time is GMT +2 (CLT)

The chart displays prices at discrete points in time; it does not display all changes between every two points. It can be useful to check how close current price is to the average price. Right now, the average for CPU cluster machines is based on 659 readings and the one for GPU is based on 679 readings. These are all readings available since March 20th 2:00 pm.

Currently the chart is updated manually and I will be working on automating the process. I will keep it available in a separate page in the blog. Stay tuned for another post about how the chart is created.

Sony: 10 million credit card accounts may have been exposed

2011-05-01T15:01:00.000-07:00

Sony apologizes, says 10 million credit card accounts may have been exposed in network attack | Technology | Los Angeles Times:

"Sony has maintained that the company acted as quickly as it could to ascertain the nature of the break-in, hire security experts and assess the scope of the damage. During the news conference, Hirai offered a time line of the events, saying the company was notified of the intrusion on April 19 and shut down the service on April 20 to investigate. It hired three firms to conduct a forensic analysis of its computers."

PayPal alternatives in Egypt - Part 2

2011-04-28T17:39:00.000-07:00

In part one of this post, I listed three online payment services that work in Egypt. I compared between the them to see which one suits my needs. The scenario I'm using is when a user is paying me money using his/her own credit card. You can see the comparison in the table below. The values in the table can be used only for reference because different options are available in each site with different fees.

	2CheckOut.com	AlertPay.com	MoneyBookers.com
Account setup fee	$49 ^*	-	-
Monthly fee	-	-	$19.99 ^**
Fixed transaction fee	$0.45 ^***	$0.25 ^***	$0.35 ^***
% transaction fee	5.5% ^***	4.9% ^***	3.9% ^***
Currency exchange fee	-	2.5%	-
Withdrawal fees	Wire $10 Check $4	Wire $15 Check $4 Credit Card $5	Wire €1.8 ~ $2.7
Users paying money need to sign in	No	Yes	No

^*Sign up is free but account setup fee is to be paid before transactions are made.

^**Only if you use website payment gateway; using payment to email address is free.

^***Default fee; fee actually varies according to account type and/or website content.

Here is a quick example of what your account will be credited if you receive a payment of $10 and $100, assuming the following:

1- Setup and monthly fees are excluded

2- Default transaction fees are applied

3- Money is kept in your online account and not yet withdrawn to bank account

	2CheckOut.com	AlertPay.com	MoneyBookers.com
$10	$9.00	$9.26	$9.26
$100	$94.05	$94.85	$95.75

PayPal alternatives in Egypt

2011-04-10T15:52:00.000-07:00

I did some research looking for PayPal alternatives that work in Egypt. This means you can withdraw money from your online balance into a bank account in Egypt. This can be useful if you want to exchange money with someone outside Egypt (like when you do a freelancing job), or to accept payments on your website.

I found the services below but I still didn't try any of them:

Update: check more details in part 2 of the post.

Update 2: If you're looking for an alternative to PayPal to use it with eBay, then MoneyBookers is the way to go. I tried it and could successfully pay using my account that is linked to my credit card issued in Egypt. The biggest issue with eBay in Egypt remains to be shipping availability and cost.

VirtaPay

2011-04-04T14:15:00.000-07:00

VirtaPay is a virtual currency site. I've been a member for some time now and kept wondering if it will actually go live or will just be another prank. They have a very active reward program for "early bird" users. The down side is that until now, you can't do much with money you earn.

This is about to change in the following days with the introduction of "Digital Delivery" project. This will enable users to buy digital content using their credit. If this actually works as expected, I'll be able to stop wondering.

http://www.virtapay.com/

Egypt...

2011-03-27T14:42:00.000-07:00

Yes, this is where this blog is coming from.

While I'm not interested in blogging about politics and current events (and believe me there is a lot going on these days in here), some of the contents of the blog will be about life in Egypt.

Wikipedia:

http://en.wikipedia.org/wiki/Egypt

Country profile by BBC:

http://news.bbc.co.uk/2/hi/europe/country_profiles/737642.stm

Map:

http://maps.google.com/maps?q=egypt&ie=UTF8&hq=&hnear=Egypt&ll=29.916852,31.201172&spn=19.740509,43.286133&z=5

My brain dump

2011-03-26T15:11:00.000-07:00

I thought this blog would be helpful to dump some thoughts and ideas. Maybe somebody finds them helpful or at least I'll know where to find them later :)