Monday, June 13

I spent the day reading papers on VAL and planning on how to tackle the querying. VAL querying is very tricky and there are two different ways to go about it, both of which I will be implementing. The first method is to "decode down" which means that if we query two columns of different segment lengths, we essentially translate the column using the longer segment length down into words of the smaller segment lengths. The alternate method is to "decode up" which means doing the opposite (translating the word with a smaller length into an equivalent using a longer length). I want to make sure that I set up my query engine correctly. I brainstormed different tools to facilitate my implementation but what I have decided to do is add a new struct activeWord which contains the aligned information ready for ANDing and ORing between columns of different segment lengths. Essentially, my code will read the next word in the compressed file, translate them into activeWord structs (decoding the appropriate column in the user-selected method of decoding), and then query the activeWord structs together (assuming that they are now correctly aligned).

I need to sleep on all of this to make sure this is how I want to set up my query engine but I'm confident this is the way I will proceed with tomorrow.