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.
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unarist 2017-11-28 04:22:27 +09:00 committed by Eugen Rochko
parent 1c5b0e3334
commit 7fb850e987
4 changed files with 32 additions and 6 deletions

View File

@ -1,6 +1,12 @@
class AddIndexAccountAndReblogOfIdToStatuses < ActiveRecord::Migration[5.1]
def change
commit_db_transaction
add_index :statuses, [:account_id, :reblog_of_id], algorithm: :concurrently
disable_ddl_transaction!
def up
# This index has been superseded by migration 20171125185353
# add_index :statuses, [:account_id, :reblog_of_id], algorithm: :concurrently
end
def down
remove_index :statuses, [:account_id, :reblog_of_id] if index_exists?(:statuses, [:account_id, :reblog_of_id])
end
end

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@ -0,0 +1,7 @@
class AddIndexReblogOfIdAndAccountToStatuses < ActiveRecord::Migration[5.1]
disable_ddl_transaction!
def change
add_index :statuses, [:reblog_of_id, :account_id], algorithm: :concurrently
end
end

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@ -0,0 +1,14 @@
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

View File

@ -10,7 +10,7 @@
#
# It's strongly recommended that you check this file into your version control system.
ActiveRecord::Schema.define(version: 20171125031751) do
ActiveRecord::Schema.define(version: 20171125190735) do
# These are extensions that must be enabled in order to support this database
enable_extension "plpgsql"
@ -409,10 +409,9 @@ ActiveRecord::Schema.define(version: 20171125031751) do
t.bigint "application_id"
t.bigint "in_reply_to_account_id"
t.index ["account_id", "id"], name: "index_statuses_on_account_id_id"
t.index ["account_id", "reblog_of_id"], name: "index_statuses_on_account_id_and_reblog_of_id"
t.index ["conversation_id"], name: "index_statuses_on_conversation_id"
t.index ["in_reply_to_id"], name: "index_statuses_on_in_reply_to_id"
t.index ["reblog_of_id"], name: "index_statuses_on_reblog_of_id"
t.index ["reblog_of_id", "account_id"], name: "index_statuses_on_reblog_of_id_and_account_id"
t.index ["uri"], name: "index_statuses_on_uri", unique: true
end