Postgres索引

Question

I am a newbie in Postgres.

We have implemented SCD type-2 in our project using Postgres. The input file is a full refresh file with approximately 30 million records daily.

Account number is the key column.

The approximate number of new records will be 20K/day. If a record is missing from the source, then that record is closed with an End date in the target. The approximate number of records being closed- 10k/day

The run time for the query is increasing steadily. Will indexing help speed up the process?

Any suggestion on the index to be used?

Answer 1

Are those 30 million records stored as each row in the database? Well if it is so, then indexing (creating and maintaining) that many records will also be a burden to the database to some extent. However, there's this new index that PostgreSQL has introduced called BRIN Index which might help you a bit. I had written a blog about this some months ago. You can have a look over it and obviously research over it more.

http://blog.bajratechnologies.com/2016/09/16/Postgres-BRIN-Index/

Answer 2

You'll have too look at the execution plans of the slow queries to be able to determine if indexes will help and what indexes you should create.

The correct index often helps a lot with a query, and with a read-only database you can create as many as you need.

You should make sure that any indexes are created after you load the table, since indexes slow down insert a lot. Either drop and recreate the table before the daily load or truncate and drop all the indexes.