Postgres索引？

Question

I am a newbie in postgres. I have a column named host (string varchar2) in a table which has around 20 million rows. How do I use indexing to optimize my search to find particular host. Also, this column will be updated daily do I need to write trigger indexing at particular interval? If yes, how do I do that? (For Records I am using Ruby and Rails 3)

Answer 1

Assuming you're doing exact matches, you should just be able to create the index and leave it:

CREATE INDEX host_index ON table_name (host)

The query optimizer should just use that automatically.

You may wish to specify other options such as the collation to use.

See the PostgreSQL docs for CREATE INDEX for more information.

Answer 2

我建议使用BRIN Index因为它是从PostgreSQL 9.5引入的，而不是传统的btree索引。

Answer 3

For text search, it is recommended that you use GIN or GiST index types.

https://www.postgresql.org/docs/9.5/static/textsearch-indexes.html

Another possibility is that if you were only performing exact matching in the host column, ie, no inequality comparisons ( > , < ) and partial matching ( like , wildcard) involved, you may consider converting host to a hash integer to speed up the search significantly.