GraphQL - Preload parent in group epics query (!43323) · Merge requests · GitLab.org / GitLab

Eugenia Grieff requested to merge 210553-improve-performance-of-graphql-groupepics-query-2 into master Sep 24, 2020

What does this MR do?

Fixes N+1 queries for the parent field in group epics by using the Lookahead feature to preload the field. After this change, we can see the number of queries against the epics table reduced:

Query

{
  group(fullPath: "gitlab-org") {
    epics {
      edges {
        node {
          parent {
	    title
          }
        }
      }
    }
  }
}

Before preloading field

Started POST "/api/graphql" for 127.0.0.1 at 2020-09-24 15:13:45 +0100
Processing by GraphqlController#execute as */*
  Parameters: {"query"=>"query {\n  group(fullPath: \"gitlab-org\") {\n    epics {\n      edges {\n        node {\n          iid\n          parent {\n             title\n          }\n        }\n      }\n    }\n  }\n}", "variables"=>"[FILTERED]", "graphql"=>{"query"=>"query {\n  group(fullPath: \"gitlab-org\") {\n    epics {\n      edges {\n        node {\n          iid\n          parent {\n             title\n          }\n        }\n      }\n    }\n  }\n}", "variables"=>"[FILTERED]"}}
  [1m[36mUser Load (0.7ms)[0m  [1m[34mSELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2[0m  [["id", 1], ["LIMIT", 1]]
  ↳ lib/gitlab/graphql/loaders/full_path_model_loader.rb:18:in `block in find'
  [1m[36mLicense Load (0.3ms)[0m  [1m[34mSELECT "licenses".* FROM "licenses" ORDER BY "licenses"."id" DESC LIMIT $1[0m  [["LIMIT", 100]]
  ↳ ee/app/models/license.rb:258:in `load_license'
  [1m[36mIpRestriction Load (0.3ms)[0m  [1m[34mSELECT "ip_restrictions".* FROM "ip_restrictions" WHERE "ip_restrictions"."group_id" = $1[0m  [["group_id", 22]]
  ↳ ee/lib/gitlab/ip_restriction/enforcer.rb:31:in `allows_address?'
  [1m[36mGroup Load (0.6ms)[0m  [1m[34mSELECT "namespaces".* FROM "namespaces" WHERE "namespaces"."type" = $1 AND "namespaces"."id" = $2 LIMIT $3[0m  [["type", "Group"], ["id", 22], ["LIMIT", 1]]
  ↳ ee/app/finders/epics_finder.rb:142:in `block in group'
  [1m[36mEpic Load (1.9ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."group_id" IN (WITH RECURSIVE "base_and_descendants" AS ((SELECT "namespaces".* FROM "namespaces" WHERE "namespaces"."type" = 'Group' AND "namespaces"."id" = 22)
UNION
(SELECT "namespaces".* FROM "namespaces", "base_and_descendants" WHERE "namespaces"."type" = 'Group' AND "namespaces"."parent_id" = "base_and_descendants"."id")) SELECT "namespaces"."id" FROM "base_and_descendants" AS "namespaces") ORDER BY "epics"."id" DESC LIMIT $1[0m  [["LIMIT", 2000]]
  ↳ lib/gitlab/graphql/pagination/keyset/connection.rb:100:in `nodes'
  [1m[36mGroup Load (0.5ms)[0m  [1m[34mSELECT "namespaces".* FROM "namespaces" WHERE "namespaces"."type" = $1 AND "namespaces"."id" = $2[0m  [["type", "Group"], ["id", 22]]
  ↳ lib/gitlab/graphql/pagination/keyset/connection.rb:100:in `nodes'
  [1m[36mEpic Load (0.3ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."id" = $1[0m  [["id", 80]]
  ↳ lib/gitlab/graphql/loaders/batch_model_loader.rb:21:in `block (2 levels) in find'
  [1m[36mEpic Load (0.4ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."id" = $1[0m  [["id", 0]]
  ↳ lib/gitlab/graphql/loaders/batch_model_loader.rb:21:in `block (2 levels) in find'
  [1m[36mEpic Load (0.4ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."id" = $1[0m  [["id", 78]]
  ↳ lib/gitlab/graphql/loaders/batch_model_loader.rb:21:in `block (2 levels) in find'
  [1m[36mEpic Load (0.5ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."id" IN ($1, $2)[0m  [["id", 0], ["id", 76]]
  ↳ lib/gitlab/graphql/loaders/batch_model_loader.rb:21:in `block (2 levels) in find'
  [1m[36mEpic Load (0.4ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."id" IN ($1, $2)[0m  [["id", 0], ["id", 74]]
  ↳ lib/gitlab/graphql/loaders/batch_model_loader.rb:21:in `block (2 levels) in find'
  [1m[36mEpic Load (0.4ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."id" IN ($1, $2)[0m  [["id", 0], ["id", 70]]
  ↳ lib/gitlab/graphql/loaders/batch_model_loader.rb:21:in `block (2 levels) in find'
  [1m[36mEpic Load (0.5ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."id" = $1[0m  [["id", 71]]
  ↳ lib/gitlab/graphql/loaders/batch_model_loader.rb:21:in `block (2 levels) in find'
  [1m[36mEpic Load (0.4ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."id" IN ($1, $2)[0m  [["id", 0], ["id", 64]]
  ↳ lib/gitlab/graphql/loaders/batch_model_loader.rb:21:in `block (2 levels) in find'
  [1m[36mEpic Load (0.4ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."id" IN ($1, $2, $3)[0m  [["id", 64], ["id", 0], ["id", 53]]
  ↳ lib/gitlab/graphql/loaders/batch_model_loader.rb:21:in `block (2 levels) in find'
  [1m[36mEpic Load (0.5ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."id" IN ($1, $2, $3)[0m  [["id", 53], ["id", 0], ["id", 47]]
  ↳ lib/gitlab/graphql/loaders/batch_model_loader.rb:21:in `block (2 levels) in find'
  [1m[36mEpic Load (0.5ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."id" IN ($1, $2, $3)[0m  [["id", 47], ["id", 0], ["id", 41]]
  ↳ lib/gitlab/graphql/loaders/batch_model_loader.rb:21:in `block (2 levels) in find'
  [1m[36mEpic Load (0.5ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."id" IN ($1, $2, $3)[0m  [["id", 41], ["id", 0], ["id", 1]]
  ↳ lib/gitlab/graphql/loaders/batch_model_loader.rb:21:in `block (2 levels) in find'
Completed 200 OK in 2690ms (Views: 1.0ms | ActiveRecord: 58.3ms | Elasticsearch: 0.0ms | Allocations: 2202355)

After preloading field

Started POST "/api/graphql" for 127.0.0.1 at 2020-09-24 15:15:39 +0100
Processing by GraphqlController#execute as */*
  Parameters: {"query"=>"query {\n  group(fullPath: \"gitlab-org\") {\n    epics {\n      edges {\n        node {\n          iid\n          parent {\n             title\n          }\n        }\n      }\n    }\n  }\n}", "variables"=>"[FILTERED]", "graphql"=>{"query"=>"query {\n  group(fullPath: \"gitlab-org\") {\n    epics {\n      edges {\n        node {\n          iid\n          parent {\n             title\n          }\n        }\n      }\n    }\n  }\n}", "variables"=>"[FILTERED]"}}
  ↳ lib/gitlab/graphql/loaders/full_path_model_loader.rb:18:in `block in find'
  [1m[36mLicense Load (0.3ms)[0m  [1m[34mSELECT "licenses".* FROM "licenses" ORDER BY "licenses"."id" DESC LIMIT $1[0m  [["LIMIT", 100]]
  ↳ ee/app/models/license.rb:258:in `load_license'
  [1m[36mIpRestriction Load (0.6ms)[0m  [1m[34mSELECT "ip_restrictions".* FROM "ip_restrictions" WHERE "ip_restrictions"."group_id" = $1[0m  [["group_id", 22]]
  ↳ ee/lib/gitlab/ip_restriction/enforcer.rb:31:in `allows_address?'
  [1m[36mGroup Load (0.6ms)[0m  [1m[34mSELECT "namespaces".* FROM "namespaces" WHERE "namespaces"."type" = $1 AND "namespaces"."id" = $2 LIMIT $3[0m  [["type", "Group"], ["id", 22], ["LIMIT", 1]]
  ↳ ee/app/finders/epics_finder.rb:142:in `block in group'
  [1m[36mEpic Load (1.7ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."group_id" IN (WITH RECURSIVE "base_and_descendants" AS ((SELECT "namespaces".* FROM "namespaces" WHERE "namespaces"."type" = 'Group' AND "namespaces"."id" = 22)
UNION
(SELECT "namespaces".* FROM "namespaces", "base_and_descendants" WHERE "namespaces"."type" = 'Group' AND "namespaces"."parent_id" = "base_and_descendants"."id")) SELECT "namespaces"."id" FROM "base_and_descendants" AS "namespaces") ORDER BY "epics"."id" DESC LIMIT $1[0m  [["LIMIT", 2000]]
  ↳ lib/gitlab/graphql/pagination/keyset/connection.rb:100:in `nodes'
  [1m[36mGroup Load (0.4ms)[0m  [1m[34mSELECT "namespaces".* FROM "namespaces" WHERE "namespaces"."type" = $1 AND "namespaces"."id" = $2[0m  [["type", "Group"], ["id", 22]]
  ↳ lib/gitlab/graphql/pagination/keyset/connection.rb:100:in `nodes'
  [1m[36mEpic Load (0.5ms)[0m  [1m[34mSELECT "epics".* FROM "epics" WHERE "epics"."id" IN ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11)[0m  [["id", 80], ["id", 78], ["id", 76], ["id", 74], ["id", 70], ["id", 71], ["id", 64], ["id", 53], ["id", 47], ["id", 41], ["id", 1]]
  ↳ lib/gitlab/graphql/pagination/keyset/connection.rb:100:in `nodes'
Completed 200 OK in 2765ms (Views: 1.0ms | ActiveRecord: 52.6ms | Elasticsearch: 0.0ms | Allocations: 2150721)

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Edited Sep 29, 2020 by Eugenia Grieff

GraphQL - Preload parent in group epics query