User search: Remove trigram and refactor the module

- Remove trigram as it tends to rank garbage results highly, resulting
in it prioritized above fts, which gives actually decent results. ACKed
by kaniini and lain on irc.
- Remove a test for handling misspelled requests, since we no longer have
trigram
- Remove a test for searching users with `nil` display names, because it
is unrealistic, we don't accept usernames that are not >1 char strings
- Make rank boosting for followers/followees sane again, previous values
resulted in garbage matches getting on top just because the users are
followers/followees
This commit is contained in:
rinpatch 2019-10-16 12:52:47 +03:00
parent 4123c9db07
commit 713b2187b9
2 changed files with 50 additions and 119 deletions

View File

@ -4,7 +4,6 @@
defmodule Pleroma.User.Search do
alias Pleroma.Pagination
alias Pleroma.Repo
alias Pleroma.User
import Ecto.Query
@ -23,18 +22,10 @@ def search(query_string, opts \\ []) do
maybe_resolve(resolve, for_user, query_string)
{:ok, results} =
Repo.transaction(fn ->
Ecto.Adapters.SQL.query(
Repo,
"select set_limit(#{@similarity_threshold})",
[]
)
results =
query_string
|> search_query(for_user, following)
|> Pagination.fetch_paginated(%{"offset" => offset, "limit" => result_limit}, :offset)
end)
results
end
@ -56,15 +47,52 @@ defp search_query(query_string, for_user, following) do
|> base_query(following)
|> filter_blocked_user(for_user)
|> filter_blocked_domains(for_user)
|> search_subqueries(query_string)
|> union_subqueries
|> distinct_query()
|> boost_search_rank_query(for_user)
|> fts_subquery(query_string)
|> subquery()
|> where([u], u.search_rank > @similarity_threshold)
|> boost_search_rank(for_user)
|> order_by(desc: :search_rank)
|> maybe_restrict_local(for_user)
end
@nickname_regex ~r/^[a-zA-Z0-9.!#$%&'*+\/=?^_`{|}~\-@]+$/
defp fts_subquery(query, query_string) do
{nickname_weight, name_weight} =
if String.match?(query_string, @nickname_regex) do
{"A", "B"}
else
{"B", "A"}
end
query_string = to_tsquery(query_string)
from(
u in query,
select_merge: %{
search_rank:
fragment(
"""
ts_rank_cd((setweight(to_tsvector('simple', ?), ?) || setweight(to_tsvector('simple', ?), ?)), to_tsquery('simple', ?))
""",
u.name,
^name_weight,
u.nickname,
^nickname_weight,
^query_string
)
}
)
end
defp to_tsquery(query_string) do
String.trim_trailing(query_string, "@" <> local_domain())
|> String.replace(~r/[!-\/|@|[-`|{-~|:-?]+/, " ")
|> String.trim()
|> String.split()
|> Enum.map(&(&1 <> ":*"))
|> Enum.join(" | ")
end
defp base_query(_user, false), do: User
defp base_query(user, true), do: User.get_followers_query(user)
@ -87,21 +115,6 @@ defp filter_blocked_domains(query, %User{info: %{domain_blocks: domain_blocks}})
defp filter_blocked_domains(query, _), do: query
defp union_subqueries({fts_subquery, trigram_subquery}) do
from(s in trigram_subquery, union_all: ^fts_subquery)
end
defp search_subqueries(base_query, query_string) do
{
fts_search_subquery(base_query, query_string),
trigram_search_subquery(base_query, query_string)
}
end
defp distinct_query(q) do
from(s in subquery(q), order_by: s.search_type, distinct: s.id)
end
defp maybe_resolve(true, user, query) do
case {limit(), user} do
{:all, _} -> :noop
@ -126,9 +139,9 @@ defp limit, do: Pleroma.Config.get([:instance, :limit_to_local_content], :unauth
defp restrict_local(q), do: where(q, [u], u.local == true)
defp boost_search_rank_query(query, nil), do: query
defp local_domain, do: Pleroma.Config.get([Pleroma.Web.Endpoint, :url, :host])
defp boost_search_rank_query(query, for_user) do
defp boost_search_rank(query, %User{} = for_user) do
friends_ids = User.get_friends_ids(for_user)
followers_ids = User.get_followers_ids(for_user)
@ -137,8 +150,8 @@ defp boost_search_rank_query(query, for_user) do
search_rank:
fragment(
"""
CASE WHEN (?) THEN 0.5 + (?) * 1.3
WHEN (?) THEN 0.5 + (?) * 1.2
CASE WHEN (?) THEN (?) * 1.5
WHEN (?) THEN (?) * 1.3
WHEN (?) THEN (?) * 1.1
ELSE (?) END
""",
@ -154,70 +167,5 @@ defp boost_search_rank_query(query, for_user) do
)
end
@spec fts_search_subquery(User.t() | Ecto.Query.t(), String.t()) :: Ecto.Query.t()
defp fts_search_subquery(query, term) do
processed_query =
String.trim_trailing(term, "@" <> local_domain())
|> String.replace(~r/[!-\/|@|[-`|{-~|:-?]+/, " ")
|> String.trim()
|> String.split()
|> Enum.map(&(&1 <> ":*"))
|> Enum.join(" | ")
from(
u in query,
select_merge: %{
search_type: ^0,
search_rank:
fragment(
"""
ts_rank_cd(
setweight(to_tsvector('simple', regexp_replace(?, '\\W', ' ', 'g')), 'A') ||
setweight(to_tsvector('simple', regexp_replace(coalesce(?, ''), '\\W', ' ', 'g')), 'B'),
to_tsquery('simple', ?),
32
)
""",
u.nickname,
u.name,
^processed_query
)
},
where:
fragment(
"""
(setweight(to_tsvector('simple', regexp_replace(?, '\\W', ' ', 'g')), 'A') ||
setweight(to_tsvector('simple', regexp_replace(coalesce(?, ''), '\\W', ' ', 'g')), 'B')) @@ to_tsquery('simple', ?)
""",
u.nickname,
u.name,
^processed_query
)
)
|> User.restrict_deactivated()
end
@spec trigram_search_subquery(User.t() | Ecto.Query.t(), String.t()) :: Ecto.Query.t()
defp trigram_search_subquery(query, term) do
term = String.trim_trailing(term, "@" <> local_domain())
from(
u in query,
select_merge: %{
# ^1 gives 'Postgrex expected a binary, got 1' for some weird reason
search_type: fragment("?", 1),
search_rank:
fragment(
"similarity(?, trim(? || ' ' || coalesce(?, '')))",
^term,
u.nickname,
u.name
)
},
where: fragment("trim(? || ' ' || coalesce(?, '')) % ?", u.nickname, u.name, ^term)
)
|> User.restrict_deactivated()
end
defp local_domain, do: Pleroma.Config.get([Pleroma.Web.Endpoint, :url, :host])
defp boost_search_rank(query, _for_user), do: query
end

View File

@ -74,12 +74,6 @@ test "finds users, ranking by similarity" do
assert [u4.id, u3.id, u1.id] == Enum.map(User.search("lain@ple", for_user: u1), & &1.id)
end
test "finds users, handling misspelled requests" do
u1 = insert(:user, %{name: "lain"})
assert [u1.id] == Enum.map(User.search("laiin"), & &1.id)
end
test "finds users, boosting ranks of friends and followers" do
u1 = insert(:user)
u2 = insert(:user, %{name: "Doe"})
@ -163,17 +157,6 @@ test "find all users for unauthenticated users when `limit_to_local_content` is
Pleroma.Config.put([:instance, :limit_to_local_content], :unauthenticated)
end
test "finds a user whose name is nil" do
_user = insert(:user, %{name: "notamatch", nickname: "testuser@pleroma.amplifie.red"})
user_two = insert(:user, %{name: nil, nickname: "lain@pleroma.soykaf.com"})
assert user_two ==
User.search("lain@pleroma.soykaf.com")
|> List.first()
|> Map.put(:search_rank, nil)
|> Map.put(:search_type, nil)
end
test "does not yield false-positive matches" do
insert(:user, %{name: "John Doe"})