Being Cellfish

Stuff I wished I've found in some blog (and sometimes did)

April, 2010

Change of Address
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  • Being Cellfish

    7 tips for faster SQL queries (are really just 5)


    I like when people make lists of things and decide on how many things they want in the list before they actually make the list. Usually it means a few items on the list are not so good. And by coincidence I have found another list like that which is related to SQL and I'm seeing a pattern...

    1. Use CASE when possible instead of UPDATE - Interestingly enough the first item on the list is one of the two I think could have been left out. This is just double-dipping and not knowing when to use temp tables.
    2. Don't blindly reuse code - This is a weird performance tip for me. This is just common developer sense. So it turns out the first two things in my opinion are the ones that should never have been on the list.
    3. Do pull only tables you need - A good tip but I thought everybody knew this already...
    4. Don't double-dip - I like the choice of wording here! It's a funny way to say don't use two queries of you can do it in one and don't query the same thing multiple times.
    5. Do know when to use temp tables - I'm letting this slip through the cracks even though this is just one way of dealing with double-dipping.
    6. Do pre-stage data - A simple way to gain performance but also error prone if done without great care.
    7. Do delete and updates in batches - There are two sides to this one; if you have a big update/delete you want to split it up in smaller batches and if you have a lot of small (i.e. single) update/deletes you should execute them in batches.
  • Being Cellfish

    Team Dojo 11


    This time we decided to start a little larger project that we will work on over several dojos. This lead to more design discussions and less coding than usual but hopefully it'll pay off the next time. Interestingly enough we did one mistake that I think is common when doing TDD; focus too much on low level details. In the retrospect we decided to continue next time by adding more tests at a higher abstraction level. That will hopefully help us make better design decisions than starting with the smallest building blocks which was what happened today.

    And if you wonder what the big project is? Something inspired by CRobots but written in C#.

  • Being Cellfish

    Comment Driven Development


    It took a little more than a year for CDD to catch on... Or actually it's a new variant of CDD but who cares? Still very informative.

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