I have a series of tables which are going to be queries mostly on two columns. A timestamp table and a metric type column. My plan is to partition by date ranges which means the primary key has to include the timestamp column and the id column As far as I know there is no way to specify an index type for those columns. The metric type is a text column and will not be very selective. It will have somewhere around 200 types of metrics and they will all be short, less than ten characters. Given that there will be a lot of records I was wondering what type of index would be ideal for that column. Seems like hash indexes would be ideal because only comparison will be = and they are smaller than Btrees but for a while they were not recommended. Would hash be the best or would something work better?
