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gitlab-org--gitlab-foss/db/migrate/20181005125926_add_index_to...

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Enhance performance of counting local Uploads Add an index to the `store` column on `uploads`. This makes counting local uploads faster. Also, there is no longer need to check for objects with `store = NULL`. See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/18557 --- ### Query plans Query: ```sql SELECT COUNT(*) FROM "uploads" WHERE ("uploads"."store" = ? OR "uploads"."store" IS NULL) ``` #### Without index ``` gitlabhq_production=# EXPLAIN ANALYZE SELECT uploads.* FROM uploads WHERE (uploads.store = 1 OR uploads.store IS NULL); QUERY PLAN --------------------------------------------------------------------------------------------------------------- Seq Scan on uploads (cost=0.00..601729.54 rows=578 width=272) (actual time=6.170..2308.256 rows=545 loops=1) Filter: ((store = 1) OR (store IS NULL)) Rows Removed by Filter: 4411957 Planning time: 38.652 ms Execution time: 2308.454 ms (5 rows) ``` #### Add index ``` gitlabhq_production=# create index uploads_tmp1 on uploads (store); CREATE INDEX ``` #### With index ``` gitlabhq_production=# EXPLAIN ANALYZE SELECT uploads.* FROM uploads WHERE (uploads.store = 1 OR uploads.store IS NULL); QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------- Bitmap Heap Scan on uploads (cost=11.46..1238.88 rows=574 width=272) (actual time=0.155..0.577 rows=545 loops=1) Recheck Cond: ((store = 1) OR (store IS NULL)) Heap Blocks: exact=217 -> BitmapOr (cost=11.46..11.46 rows=574 width=0) (actual time=0.116..0.116 rows=0 loops=1) -> Bitmap Index Scan on uploads_tmp1 (cost=0.00..8.74 rows=574 width=0) (actual time=0.095..0.095 rows=545 loops=1) Index Cond: (store = 1) -> Bitmap Index Scan on uploads_tmp1 (cost=0.00..2.44 rows=1 width=0) (actual time=0.020..0.020 rows=0 loops=1) Index Cond: (store IS NULL) Planning time: 0.274 ms Execution time: 0.637 ms (10 rows) ``` Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/6070
2018-10-05 13:59:58 +00:00
# frozen_string_literal: true
Add version 4.2 to all existing migrations DB schema generated by a migration may look different in rails 4 and 5 (because rails 5 may use different default values). For this reason it's important to explicitly set for which rails version a migration was written for. See https://stackoverflow.com/questions/35929869/activerecordmigration-deprecation-warning-asks-for-rails-version-but-im-no/35930912#35930912
2018-11-13 07:27:31 +00:00
class AddIndexToUploadsStore < ActiveRecord::Migration[4.2]
Enhance performance of counting local Uploads Add an index to the `store` column on `uploads`. This makes counting local uploads faster. Also, there is no longer need to check for objects with `store = NULL`. See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/18557 --- ### Query plans Query: ```sql SELECT COUNT(*) FROM "uploads" WHERE ("uploads"."store" = ? OR "uploads"."store" IS NULL) ``` #### Without index ``` gitlabhq_production=# EXPLAIN ANALYZE SELECT uploads.* FROM uploads WHERE (uploads.store = 1 OR uploads.store IS NULL); QUERY PLAN --------------------------------------------------------------------------------------------------------------- Seq Scan on uploads (cost=0.00..601729.54 rows=578 width=272) (actual time=6.170..2308.256 rows=545 loops=1) Filter: ((store = 1) OR (store IS NULL)) Rows Removed by Filter: 4411957 Planning time: 38.652 ms Execution time: 2308.454 ms (5 rows) ``` #### Add index ``` gitlabhq_production=# create index uploads_tmp1 on uploads (store); CREATE INDEX ``` #### With index ``` gitlabhq_production=# EXPLAIN ANALYZE SELECT uploads.* FROM uploads WHERE (uploads.store = 1 OR uploads.store IS NULL); QUERY PLAN ------------------------------------------------------------------------------------------------------------------------------- Bitmap Heap Scan on uploads (cost=11.46..1238.88 rows=574 width=272) (actual time=0.155..0.577 rows=545 loops=1) Recheck Cond: ((store = 1) OR (store IS NULL)) Heap Blocks: exact=217 -> BitmapOr (cost=11.46..11.46 rows=574 width=0) (actual time=0.116..0.116 rows=0 loops=1) -> Bitmap Index Scan on uploads_tmp1 (cost=0.00..8.74 rows=574 width=0) (actual time=0.095..0.095 rows=545 loops=1) Index Cond: (store = 1) -> Bitmap Index Scan on uploads_tmp1 (cost=0.00..2.44 rows=1 width=0) (actual time=0.020..0.020 rows=0 loops=1) Index Cond: (store IS NULL) Planning time: 0.274 ms Execution time: 0.637 ms (10 rows) ``` Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/6070
2018-10-05 13:59:58 +00:00
include Gitlab::Database::MigrationHelpers
DOWNTIME = false
disable_ddl_transaction!
def up
add_concurrent_index :uploads, :store
end
def down
remove_concurrent_index :uploads, :store
end
end