Hubert Zhang created HAWQ-210: --------------------------------- Summary: Improve data locality when table size is small Key: HAWQ-210 URL: https://issues.apache.org/jira/browse/HAWQ-210 Project: Apache HAWQ Issue Type: Improvement Components: Core Reporter: Hubert Zhang Assignee: Lei Chang
Currently, data locality is based on a heuristic greedy algotirhm. First consider continue blocks for a vseg and then non continue blocks and finally non local blocks. But when a file contains several continue blocks but each vseg could only process one blocks due to avg size. In this case continue blocks are assigned to different vsegs one by one, and they are to be treated as non continue blocks. In this improvement, we try to add continue infomation to help choosing the right vseg in non continue blocks allocation stages. The main idea is to go through the blocks in a file, and find the host which include the max number of blocks in this file. We call this host as INSERT HOST. When assigning non continue blocks, we prefer INSERT HOST to other hosts when they are all local read. -- This message was sent by Atlassian JIRA (v6.3.4#6332)