Change to truncate table before adding finding_link_url_idx

See https://gitlab.com/gitlab-org/gitlab/-/merge_requests/79637

Changelog: other

db/migrate/20210811193033_add_unique_index_to_vulnerability_finding_links.rb

 # frozen_string_literal: true
 class AddUniqueIndexToVulnerabilityFindingLinks < Gitlab::Database::Migration[1.0]
-  disable_ddl_transaction!
-
-  NAME_URL_INDEX_NAME = 'finding_link_name_url_idx'
-  URL_INDEX_NAME = 'finding_link_url_idx'
+  # This migration has been moved to db/post_migrate/20220201193033_add_unique_index_to_vulnerability_finding_links_with_truncate.rb
+  # Previously, this was causing an bug where there was a conflict between the table cleanup and the index creation.
   def up
-    add_concurrent_index :vulnerability_finding_links, [:vulnerability_occurrence_id, :name, :url], unique: true, name: NAME_URL_INDEX_NAME
-    add_concurrent_index :vulnerability_finding_links, [:vulnerability_occurrence_id, :url], unique: true, where: 'name is null', name: URL_INDEX_NAME
+    # no op
   end
   def down
-    remove_concurrent_index :vulnerability_finding_links, [:vulnerability_occurrence_id, :name, :url], name: NAME_URL_INDEX_NAME
-    remove_concurrent_index :vulnerability_finding_links, [:vulnerability_occurrence_id, :url], name: URL_INDEX_NAME
+    # no op
   end
 end

db/post_migrate/20211104165220_remove_vulnerability_finding_links.rb

 # frozen_string_literal: true
 class RemoveVulnerabilityFindingLinks < Gitlab::Database::Migration[1.0]
-  BATCH_SIZE = 50_000
-  MIGRATION = 'RemoveVulnerabilityFindingLinks'
-
-  disable_ddl_transaction!
+  # This migration has been moved to a TRUNCATE in db/post_migrate/20220201193033_add_unique_index_to_vulnerability_finding_links_with_truncate.rb
+  # Previously, this was causing an bug where there was a conflict between the table cleanup and the index creation.
   def up
-    queue_background_migration_jobs_by_range_at_intervals(
-      define_batchable_model('vulnerability_finding_links'),
-      MIGRATION,
-      2.minutes,
-      batch_size: BATCH_SIZE
-    )
+    # no op
   end
   def down
-    # no ops
+    # no op
   end
 end

db/post_migrate/20211210173137_remove_vulnerability_finding_links_again.rb

 # frozen_string_literal: true
 class RemoveVulnerabilityFindingLinksAgain < Gitlab::Database::Migration[1.0]
-  BATCH_SIZE = 50_000
-  MIGRATION = 'RemoveVulnerabilityFindingLinks'
-
-  disable_ddl_transaction!
+  # This migration has been moved to a TRUNCATE in db/post_migrate/20220201193033_add_unique_index_to_vulnerability_finding_links_with_truncate.rb
+  # Previously, this was causing an bug where there was a conflict between the table cleanup and the index creation.
   def up
-    queue_background_migration_jobs_by_range_at_intervals(
-      define_batchable_model('vulnerability_finding_links'),
-      MIGRATION,
-      2.minutes,
-      batch_size: BATCH_SIZE
-    )
+    # no op
   end
   def down
-    # no ops
+    # no op
   end
 end

db/post_migrate/20220201193033_add_unique_index_to_vulnerability_finding_links_with_truncate.rb

+# frozen_string_literal: true
+
+class AddUniqueIndexToVulnerabilityFindingLinksWithTruncate < Gitlab::Database::Migration[1.0]
+  disable_ddl_transaction!
+
+  NAME_URL_INDEX_NAME = 'finding_link_name_url_idx'
+  URL_INDEX_NAME = 'finding_link_url_idx'
+
+  def up
+    execute('TRUNCATE TABLE vulnerability_finding_links')
+
+    add_concurrent_index :vulnerability_finding_links, [:vulnerability_occurrence_id, :name, :url], unique: true, name: NAME_URL_INDEX_NAME
+    add_concurrent_index :vulnerability_finding_links, [:vulnerability_occurrence_id, :url], unique: true, where: 'name is null', name: URL_INDEX_NAME
+  end
+
+  def down
+    remove_concurrent_index :vulnerability_finding_links, [:vulnerability_occurrence_id, :name, :url], name: NAME_URL_INDEX_NAME
+    remove_concurrent_index :vulnerability_finding_links, [:vulnerability_occurrence_id, :url], name: URL_INDEX_NAME
+  end
+end

db/schema_migrations/20220201193033

+92bbe74c6c3627dd26f709acd2a20f442212eab933f719be815701a3bc429539
\ No newline at end of file