Searching against a large list of people at the same time in Postgres

Question

I have a list of people that varies between 2-5k entries that has this general format:

firstname1 lastname1, firstname2 lastname2, firstname3 lastname3 ...

I have a user_table which contains about 250-300k entries with a firstname and lastname column. What I'm trying to do is let users input that list of names into a field, and return all users in the database with matching names. My first instinct was to create a view called name_search that looks like this ->

create view name_search as (
  select
    id,
    to_tsvector(concat(firstname, ' ', lastname)) as search_field
  from user_table
)

Then I can search against it by turning all the names in the comma separated list into a string like this

const queryString = "(firstname1 <-> lastname1) | (firstname2 <-> lastname2) | (firstname3 <-> lastname3) ..."

then I can pass that string into this query

select
  *
from name_search 
where search_field @@ to_tsquery(queryString)

I'm leaving out some of the details like escaping the string etc etc. but my issue is that this is horribly slow. I was wondering if someone could help me create a solution to this that is faster.

Answer 1

I don't see a case for full text search here.
You can provide your input string as is to this query:

SELECT t.id, firstname, lastname
FROM   user_table t
JOIN  (
   SELECT split_part(fullname, ' ', 1) AS firstname
        , split_part(fullname, ' ', 2) AS lastname
   FROM   unnest(string_to_array('firstname1 lastname1, firstname2 lastname2, firstname3 lastname3', ', ')) fullname
   ) input USING (firstname, lastname);

An index on (firstname, lastname) should help performance while the input list isn't too long. For retrieving more than a couple percent of all rows, a sequential scan is faster anyway.

Related:

• Split comma separated column data into additional columns
• PostgreSQL importing thousands of columns as an array
• How do I insert a row which contains a foreign key?