chinwagsocial/db/migrate/20171125190735_remove_old_reblog_index_on_statuses.rb
unarist 7fb850e987 Merge indexes for reblog on statuses table (#5831)
We added an index for `[account_id, reblog_of_id]`, but we already have a similar index for `reblog_of_id`. Those index will be bigger according to statuses count. For example, `reblog_of_id` index uses 800MB for 10GB statuses table.

So this patch swaps indexed columns like `[reblog_of_id, account_id]`, then it will covers both usage with single index.

Since those index creation may take a while, I've also disabled previous index creation.
2017-11-27 20:22:27 +01:00

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Ruby

class RemoveOldReblogIndexOnStatuses < ActiveRecord::Migration[5.1]
disable_ddl_transaction!
def up
# This index may not exists (see migration 20171122120436)
remove_index :statuses, [:account_id, :reblog_of_id] if index_exists?(:statuses, [:account_id, :reblog_of_id])
remove_index :statuses, :reblog_of_id
end
def down
add_index :statuses, :reblog_of_id, algorithm: :concurrently
end
end