Add Index on posts.(type,status) and posts.create_time to Accelerate Query

Created by: wtune

Problem

Missing index on table posts column create_time and (type, status) might make the underlying query slow. From PostService、BasePostService and other related file, we can find that we always read posts by type(DiscriminatorColumn, 0 for posts and 1 for sheet) and status order by create_time and sometimes insert or update, so adding index on these column can improve the query efficiency significantly.

Possible Solution

Add Index on posts.(type,status) and posts.create_time