@Kaniz Fatma​ I have read the documentation. The question is not about general guidelines regarding partitions and zordering, it is very specifically about the (potential) benefit of zordering when reading single files. To rephrase: is the only advantage of zordering that it allows the skipping of whole files, or is there also some benefit to it after a file has been selected to be read. Does it allow faster searching inside the selected files, or maybe reading only chunks of the files?