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799a45a291
The `notifications.id` column is the most probable column to run out of values. This is because it is an `int` column that has only 2147483647 values and many notifications are generated on a regular basis in an active community. This commit migrates the column to `bigint`. These migrations do not use `ALTER TABLE ... COLUMN ... TYPE` in order to avoid the `ACCESS EXCLUSIVE` lock on the entire table. Instead, they create a new `bigint` column, copy the values to the new column and then sets the new column as primary key. Related columns (see `user_badges`, `shelved_notifications`) will be migrated in a follow-up commit.
40 lines
1.2 KiB
Ruby
40 lines
1.2 KiB
Ruby
# frozen_string_literal: true
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class CopyNotificationsIdIndexes < ActiveRecord::Migration[7.0]
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disable_ddl_transaction!
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def up
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# Short-circuit if the table has been migrated already
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result =
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execute(
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"SELECT data_type FROM information_schema.columns WHERE table_name = 'notifications' AND column_name = 'id' LIMIT 1",
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)
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data_type = result[0]["data_type"]
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return if data_type.downcase == "bigint"
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# Copy existing indexes and suffix them with `_bigint`
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results =
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execute(
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"SELECT indexname, indexdef FROM pg_indexes WHERE tablename = 'notifications' AND indexdef SIMILAR TO '%\\mid\\M%'",
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)
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results.each do |res|
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indexname, indexdef = res["indexname"], res["indexdef"]
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indexdef = indexdef.gsub(/\b#{indexname}\b/, "#{indexname}_bigint")
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indexdef =
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indexdef.gsub(
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/\bCREATE (UNIQUE )?INDEX\b/,
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"CREATE \\1INDEX CONCURRENTLY",
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) if !Rails.env.test?
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indexdef = indexdef.gsub(/\bid\b/, "new_id")
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execute "DROP INDEX #{Rails.env.test? ? "" : "CONCURRENTLY"} IF EXISTS #{indexname}_bigint"
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execute(indexdef)
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end
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end
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def down
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raise ActiveRecord::IrreversibleMigration
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end
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end
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