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author | Yorick Peterse <yorickpeterse@gmail.com> | 2018-02-15 21:34:44 +0300 |
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committer | Yorick Peterse <yorickpeterse@gmail.com> | 2018-02-22 20:55:36 +0300 |
commit | 41bfe82b7a650f21b19a25204dde5a0eaf960d0f (patch) | |
tree | 5c797744a0ac593b8b11f45a30495377ab01b7e4 /lib/gitlab | |
parent | d2e43fbde60589c905aae9d2500c63355ba8fdc4 (diff) |
Optimise searching for users using short queries
This optimises searching for users when using queries consisting out of
one or two characters such as "ab". We optimise such cases by searching
for `LOWER(name)` and `LOWER(username)` instead of using `ILIKE`. Using
`LOWER` produces a _much_ better performing query.
For example, when searching for all users matching the term "a" we'd
produce the following plan:
Limit (cost=637.69..637.74 rows=20 width=805) (actual time=41.983..41.995 rows=20 loops=1)
Buffers: shared hit=8330
-> Sort (cost=637.69..638.61 rows=368 width=805) (actual time=41.982..41.990 rows=20 loops=1)
Sort Key: (CASE WHEN ((name)::text = 'a'::text) THEN 0 WHEN ((username)::text = 'a'::text) THEN 1 WHEN ((email)::text = 'a'::text) THEN 2 ELSE 3 END), name
Sort Method: top-N heapsort Memory: 35kB
Buffers: shared hit=8330
-> Bitmap Heap Scan on users (cost=75.47..627.89 rows=368 width=805) (actual time=9.452..41.305 rows=277 loops=1)
Recheck Cond: (((name)::text ~~* 'a'::text) OR ((username)::text ~~* 'a'::text) OR ((email)::text = 'a'::text))
Rows Removed by Index Recheck: 7601
Heap Blocks: exact=7636
Buffers: shared hit=8327
-> BitmapOr (cost=75.47..75.47 rows=368 width=0) (actual time=8.290..8.290 rows=0 loops=1)
Buffers: shared hit=691
-> Bitmap Index Scan on index_users_on_name_trigram (cost=0.00..38.85 rows=180 width=0) (actual time=4.369..4.369 rows=4071 loops=1)
Index Cond: ((name)::text ~~* 'a'::text)
Buffers: shared hit=360
-> Bitmap Index Scan on index_users_on_username_trigram (cost=0.00..34.41 rows=188 width=0) (actual time=3.896..3.896 rows=4140 loops=1)
Index Cond: ((username)::text ~~* 'a'::text)
Buffers: shared hit=328
-> Bitmap Index Scan on users_email_key (cost=0.00..1.94 rows=1 width=0) (actual time=0.022..0.022 rows=0 loops=1)
Index Cond: ((email)::text = 'a'::text)
Buffers: shared hit=3
Planning time: 3.912 ms
Execution time: 42.171 ms
With the changes in this commit we now produce the following plan
instead:
Limit (cost=13257.48..13257.53 rows=20 width=805) (actual time=1.567..1.579 rows=20 loops=1)
Buffers: shared hit=287
-> Sort (cost=13257.48..13280.93 rows=9379 width=805) (actual time=1.567..1.572 rows=20 loops=1)
Sort Key: (CASE WHEN ((name)::text = 'a'::text) THEN 0 WHEN ((username)::text = 'a'::text) THEN 1 WHEN ((email)::text = 'a'::text) THEN 2 ELSE 3 END), name
Sort Method: top-N heapsort Memory: 35kB
Buffers: shared hit=287
-> Bitmap Heap Scan on users (cost=135.66..13007.91 rows=9379 width=805) (actual time=0.194..1.107 rows=277 loops=1)
Recheck Cond: ((lower((name)::text) = 'a'::text) OR (lower((username)::text) = 'a'::text) OR ((email)::text = 'a'::text))
Heap Blocks: exact=277
Buffers: shared hit=287
-> BitmapOr (cost=135.66..135.66 rows=9379 width=0) (actual time=0.152..0.152 rows=0 loops=1)
Buffers: shared hit=10
-> Bitmap Index Scan on yorick_test_users (cost=0.00..124.75 rows=9377 width=0) (actual time=0.101..0.101 rows=277 loops=1)
Index Cond: (lower((name)::text) = 'a'::text)
Buffers: shared hit=4
-> Bitmap Index Scan on index_on_users_lower_username (cost=0.00..1.94 rows=1 width=0) (actual time=0.035..0.035 rows=1 loops=1)
Index Cond: (lower((username)::text) = 'a'::text)
Buffers: shared hit=3
-> Bitmap Index Scan on users_email_key (cost=0.00..1.94 rows=1 width=0) (actual time=0.014..0.014 rows=0 loops=1)
Index Cond: ((email)::text = 'a'::text)
Buffers: shared hit=3
Planning time: 0.303 ms
Execution time: 1.687 ms
Here we can see the new query is 25 times faster compared to the old
query.
Diffstat (limited to 'lib/gitlab')
-rw-r--r-- | lib/gitlab/sql/pattern.rb | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/lib/gitlab/sql/pattern.rb b/lib/gitlab/sql/pattern.rb index 5f0c98cb5a4..0e3a93aa236 100644 --- a/lib/gitlab/sql/pattern.rb +++ b/lib/gitlab/sql/pattern.rb @@ -25,7 +25,11 @@ module Gitlab query.length >= MIN_CHARS_FOR_PARTIAL_MATCHING end - def fuzzy_arel_match(column, query) + # column - The column name to search in. + # query - The text to search for. + # lower_exact_match - When set to `true` we'll fall back to using + # `LOWER(column) = query` instead of using `ILIKE`. + def fuzzy_arel_match(column, query, lower_exact_match: false) query = query.squish return nil unless query.present? @@ -34,9 +38,17 @@ module Gitlab if words.any? words.map { |word| arel_table[column].matches(to_pattern(word)) }.reduce(:and) else + sanitized_query = sanitize_sql_like(query) + # No words of at least 3 chars, but we can search for an exact # case insensitive match with the query as a whole - arel_table[column].matches(sanitize_sql_like(query)) + if lower_exact_match + Arel::Nodes::NamedFunction + .new('LOWER', [arel_table[column]]) + .eq(sanitized_query) + else + arel_table[column].matches(sanitized_query) + end end end |