Question

I have the following 3 tables:

publications (primary key = article)

article | title | pubType 

authors (primary key = *author_name*)

author_name | author_somethingelse

pub_author_map

article | author_name 

Given a value for pubType, I need to select information about the articles, including authors. To do this, I have

SELECT p.article, p.title, p.dateTime, pam.author_name FROM publications p 
LEFT JOIN pub_author_map pam ON pam.article = p.article
LEFT JOIN authors a ON a.author_name = pam.author_name
WHERE p.pubType = '$pubType' ORDER BY p.article LIMIT 10

Even with a LIMIT 10, this query clocked in at about 29s. There are 1500 rows in publications and 3000 rows in pub_author_map.

How can I optimize the above query?

Answer 1

Add indicies

• pub_author_map on column article

• publications on column pubType

for example like this.

CREATE INDEX pub_author_idx_1 
    ON pub_author_map (article);

CREATE INDEX publications_idx_1
    ON publications (pubType);