Migrations: delete contexts with BaseMigrator

Due to the lengthiness of this task, the migration has been adapted into
a BaseMigrator migration, running in the background instead.
This commit is contained in:
Hélène 2022-08-15 01:15:23 +02:00
parent bb02ee99f5
commit 88c1c76d3e
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6 changed files with 173 additions and 6 deletions

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@ -673,6 +673,8 @@ config :pleroma, :features, improved_hashtag_timeline: :auto
config :pleroma, :populate_hashtags_table, fault_rate_allowance: 0.01
config :pleroma, :delete_context_objects, fault_rate_allowance: 0.01
config :pleroma, :env, Mix.env()
config :http_signatures,

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@ -495,6 +495,27 @@ config :pleroma, :config_description, [
}
]
},
%{
group: :pleroma,
key: :delete_context_objects,
type: :group,
description: "`delete_context_objects` background migration settings",
children: [
%{
key: :fault_rate_allowance,
type: :float,
description:
"Max accepted rate of objects that failed in the migration. Any value from 0.0 which tolerates no errors to 1.0 which will enable the feature even if context object deletion failed for all records.",
suggestions: [0.01]
},
%{
key: :sleep_interval_ms,
type: :integer,
description:
"Sleep interval between each chunk of processed records in order to decrease the load on the system (defaults to 0 and should be keep default on most instances)."
}
]
},
%{
group: :pleroma,
key: :instance,

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@ -238,7 +238,8 @@ defmodule Pleroma.Application do
defp background_migrators do
[
Pleroma.Migrators.HashtagsTableMigrator
Pleroma.Migrators.HashtagsTableMigrator,
Pleroma.Migrators.ContextObjectsDeletionMigrator
]
end

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@ -42,4 +42,5 @@ defmodule Pleroma.DataMigration do
end
def populate_hashtags_table, do: get_by_name("populate_hashtags_table")
def delete_context_objects, do: get_by_name("delete_context_objects")
end

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@ -0,0 +1,139 @@
# Pleroma: A lightweight social networking server
# Copyright © 2017-2022 Pleroma Authors <https://pleroma.social/>
# SPDX-License-Identifier: AGPL-3.0-only
defmodule Pleroma.Migrators.ContextObjectsDeletionMigrator do
defmodule State do
use Pleroma.Migrators.Support.BaseMigratorState
@impl Pleroma.Migrators.Support.BaseMigratorState
defdelegate data_migration(), to: Pleroma.DataMigration, as: :delete_context_objects
end
use Pleroma.Migrators.Support.BaseMigrator
alias Pleroma.Migrators.Support.BaseMigrator
alias Pleroma.Object
@doc "This migration removes objects created exclusively for contexts, containing only an `id` field."
@impl BaseMigrator
def feature_config_path, do: [:features, :delete_context_objects]
@impl BaseMigrator
def fault_rate_allowance, do: Config.get([:delete_context_objects, :fault_rate_allowance], 0)
@impl BaseMigrator
def perform do
data_migration_id = data_migration_id()
max_processed_id = get_stat(:max_processed_id, 0)
Logger.info("Deleting context objects from `objects` (from oid: #{max_processed_id})...")
query()
|> where([object], object.id > ^max_processed_id)
|> Repo.chunk_stream(100, :batches, timeout: :infinity)
|> Stream.each(fn objects ->
object_ids = Enum.map(objects, & &1.id)
results = Enum.map(object_ids, &delete_context_object(&1))
failed_ids =
results
|> Enum.filter(&(elem(&1, 0) == :error))
|> Enum.map(&elem(&1, 1))
chunk_affected_count =
results
|> Enum.filter(&(elem(&1, 0) == :ok))
|> length()
for failed_id <- failed_ids do
_ =
Repo.query(
"INSERT INTO data_migration_failed_ids(data_migration_id, record_id) " <>
"VALUES ($1, $2) ON CONFLICT DO NOTHING;",
[data_migration_id, failed_id]
)
end
_ =
Repo.query(
"DELETE FROM data_migration_failed_ids " <>
"WHERE data_migration_id = $1 AND record_id = ANY($2)",
[data_migration_id, object_ids -- failed_ids]
)
max_object_id = Enum.at(object_ids, -1)
put_stat(:max_processed_id, max_object_id)
increment_stat(:iteration_processed_count, length(object_ids))
increment_stat(:processed_count, length(object_ids))
increment_stat(:failed_count, length(failed_ids))
increment_stat(:affected_count, chunk_affected_count)
put_stat(:records_per_second, records_per_second())
persist_state()
# A quick and dirty approach to controlling the load this background migration imposes
sleep_interval = Config.get([:delete_context_objects, :sleep_interval_ms], 0)
Process.sleep(sleep_interval)
end)
|> Stream.run()
end
@impl BaseMigrator
def query do
# Context objects have no activity type, and only one field, `id`.
# Only those context objects are without types.
from(
object in Object,
where: fragment("(?)->'type' IS NULL", object.data),
select: %{
id: object.id
}
)
end
@spec delete_context_object(integer()) :: {:ok | :error, integer()}
defp delete_context_object(id) do
result =
%Object{id: id}
|> Repo.delete()
|> elem(0)
{result, id}
end
@impl BaseMigrator
def retry_failed do
data_migration_id = data_migration_id()
failed_objects_query()
|> Repo.chunk_stream(100, :one)
|> Stream.each(fn object ->
with {res, _} when res != :error <- delete_context_object(object.id) do
_ =
Repo.query(
"DELETE FROM data_migration_failed_ids " <>
"WHERE data_migration_id = $1 AND record_id = $2",
[data_migration_id, object.id]
)
end
end)
|> Stream.run()
put_stat(:failed_count, failures_count())
persist_state()
force_continue()
end
defp failed_objects_query do
from(o in Object)
|> join(:inner, [o], dmf in fragment("SELECT * FROM data_migration_failed_ids"),
on: dmf.record_id == o.id
)
|> where([_o, dmf], dmf.data_migration_id == ^data_migration_id())
|> order_by([o], asc: o.id)
end
end

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@ -3,13 +3,16 @@ defmodule Pleroma.Repo.Migrations.DataMigrationDeleteContextObjects do
require Logger
@doc "This migration removes objects created exclusively for contexts, containing only an `id` field."
def up do
dt = NaiveDateTime.utc_now()
def change do
Logger.warn(
"This migration can take a very long time to execute, depending on your database size. Please be patient, Pleroma-tan is doing her best!\n"
execute(
"INSERT INTO data_migrations(name, inserted_at, updated_at) " <>
"VALUES ('delete_context_objects', '#{dt}', '#{dt}') ON CONFLICT DO NOTHING;"
)
end
execute("DELETE FROM objects WHERE (data->>'type') IS NULL;")
def down do
execute("DELETE FROM data_migrations WHERE name = 'delete_context_objects';")
end
end