2 ms·
After skimming the paper, I'm fairly confident it's not the same at all. We only managed the theoretical side of a scenario where there would be multiple TB har
by hvidgaard 11y ago
After skimming the paper, I'm fairly confident it's not the same at all. We only managed the theoretical side of a scenario where there would be multiple TB hard drives, on multiple machines. Any efficient algorithm would work in a scanning manner, and not seek backwards beyond what could be kept in ram. We did simulate this, and the result was quite clear, IO matters.
From the paper the following 3 quotes highlight exactly why they where CPU bound:
> We found that if we instead ran queries on uncompressed data, most queries became I/O bound
> is an artifact of the decision to write Spark in Scala, which is based on Java: after being read from disk, data must be deserialized from a byte buffer to a Java object
> for some queries, as much as half of the CPU time is spent deserializing and decompressing data