Xaprb

5 Responses to “Duplicate index checker version 1.9 released”

1. 1 Roland Bouman
   Oct 1st, 2006 at 8:58 pm

   Hi Baron,

   great to hear you got round the bug…let’s hope it gets fixed anyway :)

   By the way, what’s your take on the column prefixes? I bumped into that when I was well into writing my article and at that point I just felt like “…oh no, not another complicating factor…”. For example, we could have:

   table (col1 varchar(1000), col2 char(1))
   
   index1 (col1(100))
   index2 (col1(1),col2)

   And if it get’s as insane as this it is likely that index1 is more selective than index2. In the end, that’s what determines the performance, and the ‘left-prefix’ criterion is just a simple and mostly effective measure for the selectivity.

2. 2 Xaprb
   Oct 2nd, 2006 at 7:37 am

   I thought about prefixes but decided not to go there. I could, though. I guess it wouldn’t be too hard to take out the parenthesized prefix notation and leave just the column names.

   Now that I think about it, I bet my regular expression breaks and doesn’t get all the column names when there’s a parenthesized prefix. I should look into this.

3. 3 Xaprb
   Oct 4th, 2006 at 7:46 pm

   Yes, prefixes made it break silently. I fixed that, and in the process made it ignore column prefixes entirely. Now these key definitions end up being exactly the same, so they will be reported as duplicates:

     PRIMARY KEY  (`day`,`account`),
     KEY `day` (`day`(12),`account`),
     KEY `day` (`day`,`account`(5)),

   Of course, they’re not really duplicates, or might not be anyway, but my whole philosophy with this tool is “catch enough problems to be helpful, then report them and let the DBA figure it out.”

4. 4 john
   Oct 5th, 2006 at 6:09 pm

   Yeah, well this whole idea isn’t very helpful to me. I need the thing to make it not do that stuff. If you could fix that it will help my employees be much more efficient. See, I run a large enterprise company that deals in interactive software that uses databases. We have a large Access database that we administrate. Let me know if you want to work for us, we could make a good offer.

5. 5 Xaprb
   Oct 5th, 2006 at 6:43 pm

   Hello my brother, I love you too :-)

   [Note: “john” above really is my brother, whose name isn’t John.]

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