39 lines
1.6 KiB
Ruby
39 lines
1.6 KiB
Ruby
# This migration creates the `versions` table, the only schema PT requires.
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# All other migrations PT provides are optional.
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class CreateVersions < ActiveRecord::Migration[7.0]
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# The largest text column available in all supported RDBMS is
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# 1024^3 - 1 bytes, roughly one gibibyte. We specify a size
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# so that MySQL will use `longtext` instead of `text`. Otherwise,
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# when serializing very large objects, `text` might not be big enough.
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TEXT_BYTES = 1_073_741_823
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def change
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create_table :versions do |t|
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t.string :item_type, null: false
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t.string :item_id, null: false
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t.string :event, null: false
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t.string :whodunnit
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#t.text :object, limit: TEXT_BYTES
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# Known issue in MySQL: fractional second precision
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# -------------------------------------------------
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#
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# MySQL timestamp columns do not support fractional seconds unless
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# defined with "fractional seconds precision". MySQL users should manually
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# add fractional seconds precision to this migration, specifically, to
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# the `created_at` column.
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# (https://dev.mysql.com/doc/refman/5.6/en/fractional-seconds.html)
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#
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# MySQL users should also upgrade to at least rails 4.2, which is the first
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# version of ActiveRecord with support for fractional seconds in MySQL.
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# (https://github.com/rails/rails/pull/14359)
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#
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# MySQL users should use the following line for `created_at`
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# t.datetime :created_at, limit: 6
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t.datetime :created_at
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end
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add_index :versions, %i(item_type item_id)
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end
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end
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