Question

I have a 2 row table pertaining of a number, and that numbers cube. Right now, I have about 13 million numbers inserted, and that’s growing very, very quickly.

Is there a faster way to output simple tables quicker than using a command like SELECT * FROM table?

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My second question pertains to the selection of a range of numbers. As stated above, I have a large database growing extremely fast to hold numbers and their cubes. If you’re wondering, I’m trying to find the 3 numbers that will sum up to 33 when cubed. So, I’m doing this by using a server/client program to send a range of numbers to a client so they can do the equations on said range of numbers.

So, for example, let’s say that the first client chimes in. I give him a range of 0, 100. He than goes off to compute the numbers and report back to tell the server if he found the triplet. If he didn’t the loop will just continue.

When the client is doing the calculations for the numbers by itself, it goes extremely slow. So, I have decided to use a database to store the cubed numbers so the client does not have to do the calculations. The problem is, I don’t know how to access only a range of numbers. For example, if the client had the range 0-100, it would need to access the cubes of all numbers from 0-100.

What is the select command that will return a range of numbers?

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The engine I am using for the table is MyISAM.

Answer 1

If your table “mytable” has two columns

number     cube
  0         0
  1         1
  2         8
  3         27

the query command will be (Assuming the start of the range is 100 and the end is 200):

select number, cube from mytable where number between 100 and 200 order by number;

If you want this query to be as fast as possible, make sure of the following:

• number is an index. Thus you don’t need to do a table scan to find the start of your range.
• the index you create is clustered. Clustered indexes are way faster for
  scans like this as the leaf in the index is the record (in comparison, the leaf in a
  non-clustered index is a pointer to the record which may be in a completely different
  part of the disk). As well, the clustered index
  forces a sorted structure on the
  data. Thus you may be able to read all 100
  records from a single block.

Of course, adding an index will make writing to the table slightly slower. As well, I am assuming you are writing to the table in order (i.e. 0,1,2,3,4 etc. not 10,5,100,3 etc.). Writes to tables with clustered indexes are very slow if you write to the table in a random order (as the DB has to keep moving records to fit the new ones in).