This is just an out of curiosity question. Let’s say you have a database table with 1m rows in it, and you want to often do queries like looking for either male or female, US or non-US, voter or non-voter etc, it’s clearly very efficient to define a bitmap index for the table in which each bit represents one either-or condition.
However, to execute the query, you still have to scan through (probably) all of the index doing a bitand to select matching rows.
My question is is there some kind of bitmap-optimized storage such that the bit ‘channels’ are pre-created in the hardware? I’m envisaging something similar to knitting needles lifting punched cards out of an old library catalog system. In other words, rather than going row by row through memory locations, the chip can just pull out the matching rows electronically because there are hardware connections for each bit channel? I’ve a feeling the brain must work something like this. If I think of ‘all blue objects’, and then restrict that to ‘all long blue objects’ and then ‘all long blue heavy objects’, my brain does it effortlessly and I’m sure it’s not scanning through all the objects I know about every time. It seems like perhaps there is some neurons that provide pathways for different dimensions for quick retrieval. I’m just wondering if there’s anything like this in the hardware world?
Thanks!
Why invent something that’s already there?
Content-addressable memory