gitlab-org--gitlab-foss/app/models/snippet.rb
Yorick Peterse d171ff6016
Rewrite SnippetsFinder to improve performance
This completely rewrites the SnippetsFinder class from the ground up in
order to improve its performance. The old code was beyond salvaging. It
was complex, included various Rails 5 workarounds, comments that
shouldn't be necessary, and most important of all: it produced a really
poorly performing database query.

As a result, I opted for rewriting the finder from scratch, instead of
trying to patch the existing code. Instead of trying to reuse as many
existing methods as possible, I opted for defining new methods
specifically meant for the SnippetsFinder. This requires some extra code
here and there, but allows us to have much more control over the
resulting SQL queries. It is these changes that then allow us to produce
a _much_ more efficient query.

To illustrate how bad the old query was, we will use my own snippets as
an example. Currently I have 52 snippets, most of which are global ones.
To retrieve these, you would run the following Ruby code:

    user = User.find_by(username: 'yorickpeterse')

    SnippetsFinder.new(user, author: user).execute

On GitLab.com the resulting query will take between 10 and 15 seconds to
run, producing the query plan found at
https://explain.depesz.com/s/Y5IX. Apart from the long execution time,
the total number of buffers (the sum of all shared hits) is around 185
GB, though the real number is probably (hopefully) much lower as I doubt
simply summing these numbers produces the true total number of buffers
used.

The new query's plan can be found at https://explain.depesz.com/s/wHdN,
and this query takes between 10 and 100-ish milliseconds to run. The
total number of buffers used is only about 30 MB.

Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/52639
2018-11-05 14:28:29 +01:00

218 lines
5.6 KiB
Ruby

# frozen_string_literal: true
class Snippet < ActiveRecord::Base
include Gitlab::VisibilityLevel
include Redactable
include CacheMarkdownField
include Noteable
include Participable
include Referable
include Sortable
include Awardable
include Mentionable
include Spammable
include Editable
include Gitlab::SQL::Pattern
include FromUnion
cache_markdown_field :title, pipeline: :single_line
cache_markdown_field :description
cache_markdown_field :content
redact_field :description
# Aliases to make application_helper#edited_time_ago_with_tooltip helper work properly with snippets.
# See https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10392/diffs#note_28719102
alias_attribute :last_edited_at, :updated_at
alias_attribute :last_edited_by, :updated_by
# If file_name changes, it invalidates content
alias_method :default_content_html_invalidator, :content_html_invalidated?
def content_html_invalidated?
default_content_html_invalidator || file_name_changed?
end
default_value_for(:visibility_level) { Gitlab::CurrentSettings.default_snippet_visibility }
belongs_to :author, class_name: 'User'
belongs_to :project
has_many :notes, as: :noteable, dependent: :destroy # rubocop:disable Cop/ActiveRecordDependent
delegate :name, :email, to: :author, prefix: true, allow_nil: true
validates :author, presence: true
validates :title, presence: true, length: { maximum: 255 }
validates :file_name,
length: { maximum: 255 }
validates :content, presence: true
validates :visibility_level, inclusion: { in: Gitlab::VisibilityLevel.values }
# Scopes
scope :are_internal, -> { where(visibility_level: Snippet::INTERNAL) }
scope :are_private, -> { where(visibility_level: Snippet::PRIVATE) }
scope :are_public, -> { where(visibility_level: Snippet::PUBLIC) }
scope :public_and_internal, -> { where(visibility_level: [Snippet::PUBLIC, Snippet::INTERNAL]) }
scope :fresh, -> { order("created_at DESC") }
scope :inc_relations_for_view, -> { includes(author: :status) }
participant :author
participant :notes_with_associations
attr_spammable :title, spam_title: true
attr_spammable :content, spam_description: true
def self.with_optional_visibility(value = nil)
if value
where(visibility_level: value)
else
all
end
end
def self.only_global_snippets
where(project_id: nil)
end
def self.only_include_projects_visible_to(current_user = nil)
levels = Gitlab::VisibilityLevel.levels_for_user(current_user)
joins(:project).where('projects.visibility_level IN (?)', levels)
end
def self.only_include_projects_with_snippets_enabled(include_private: false)
column = ProjectFeature.access_level_attribute(:snippets)
levels = [ProjectFeature::ENABLED, ProjectFeature::PUBLIC]
levels << ProjectFeature::PRIVATE if include_private
joins(project: :project_feature)
.where(project_features: { column => levels })
end
def self.only_include_authorized_projects(current_user)
where(
'EXISTS (?)',
ProjectAuthorization
.select(1)
.where('project_id = snippets.project_id')
.where(user_id: current_user.id)
)
end
def self.for_project_with_user(project, user = nil)
return none unless project.snippets_visible?(user)
if user && project.team.member?(user)
project.snippets
else
project.snippets.public_to_user(user)
end
end
def self.visible_to_or_authored_by(user)
where(
'snippets.visibility_level IN (?) OR snippets.author_id = ?',
Gitlab::VisibilityLevel.levels_for_user(user),
user.id
)
end
def self.reference_prefix
'$'
end
# Pattern used to extract `$123` snippet references from text
#
# This pattern supports cross-project references.
def self.reference_pattern
@reference_pattern ||= %r{
(#{Project.reference_pattern})?
#{Regexp.escape(reference_prefix)}(?<snippet>\d+)
}x
end
def self.link_reference_pattern
@link_reference_pattern ||= super("snippets", /(?<snippet>\d+)/)
end
def to_reference(from = nil, full: false)
reference = "#{self.class.reference_prefix}#{id}"
if project.present?
"#{project.to_reference(from, full: full)}#{reference}"
else
reference
end
end
def self.content_types
[
".rb", ".py", ".pl", ".scala", ".c", ".cpp", ".java",
".haml", ".html", ".sass", ".scss", ".xml", ".php", ".erb",
".js", ".sh", ".coffee", ".yml", ".md"
]
end
def blob
@blob ||= Blob.decorate(SnippetBlob.new(self), nil)
end
def hook_attrs
attributes
end
def file_name
super.to_s
end
def sanitized_file_name
file_name.gsub(/[^a-zA-Z0-9_\-\.]+/, '')
end
def visibility_level_field
:visibility_level
end
def notes_with_associations
notes.includes(:author)
end
def check_for_spam?
visibility_level_changed?(to: Snippet::PUBLIC) ||
(public? && (title_changed? || content_changed?))
end
def spammable_entity_type
'snippet'
end
class << self
# Searches for snippets with a matching title or file name.
#
# This method uses ILIKE on PostgreSQL and LIKE on MySQL.
#
# query - The search query as a String.
#
# Returns an ActiveRecord::Relation.
def search(query)
fuzzy_search(query, [:title, :file_name])
end
# Searches for snippets with matching content.
#
# This method uses ILIKE on PostgreSQL and LIKE on MySQL.
#
# query - The search query as a String.
#
# Returns an ActiveRecord::Relation.
def search_code(query)
fuzzy_search(query, [:content])
end
def parent_class
::Project
end
end
end