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693c66dfde
The intent of the previous concatenation was to minimize object
allocations, which can end up being a slow killer. However, it turns
out that under MRI 2.4.x, the shove-strings-in-an-array-and-join method
is not only arguably more common but (in this particular case) actually
allocates *fewer* objects than the string concatenation.
Or, at least, that's what I gather by running this:
words = %w(palmettoes nudged hibernation bullish stockade's tightened Hades
Dixie's formalize superego's commissaries Zappa's viceroy's apothecaries
tablespoonful's barons Chennai tollgate ticked expands)
a = Account.first
KeywordMute.transaction do
words.each { |w| KeywordMute.create!(keyword: w, account: a) }
GC.start
s1 = GC.stat
re = String.new.tap do |str|
scoped = KeywordMute.where(account: a)
keywords = scoped.select(:id, :keyword)
count = scoped.count
keywords.find_each.with_index do |kw, index|
str << Regexp.escape(kw.keyword.strip)
str << '|' if index < count - 1
end
end
s2 = GC.stat
puts s1.inspect, s2.inspect
raise ActiveRecord::Rollback
end
vs this:
words = %w( palmettoes nudged hibernation bullish stockade's tightened Hades Dixie's
formalize superego's commissaries Zappa's viceroy's apothecaries tablespoonful's
barons Chennai tollgate ticked expands
)
a = Account.first
KeywordMute.transaction do
words.each { |w| KeywordMute.create!(keyword: w, account: a) }
GC.start
s1 = GC.stat
re = [].tap do |arr|
KeywordMute.where(account: a).select(:keyword, :id).find_each do |m|
arr << Regexp.escape(m.keyword.strip)
end
end.join('|')
s2 = GC.stat
puts s1.inspect, s2.inspect
raise ActiveRecord::Rollback
end
Using rails r, here is a comparison of the total_allocated_objects and
malloc_increase_bytes GC stat data:
total_allocated_objects malloc_increase_bytes
string concat 3200241 -> 3201428 (+1187) 1176 -> 45216 (44040)
array join 3200380 -> 3201299 (+919) 1176 -> 36448 (35272)
|
||
|---|---|---|
| .. | ||
| concerns | ||
| form | ||
| web | ||
| account.rb | ||
| account_domain_block.rb | ||
| account_filter.rb | ||
| account_moderation_note.rb | ||
| application_record.rb | ||
| block.rb | ||
| context.rb | ||
| conversation.rb | ||
| conversation_mute.rb | ||
| custom_emoji.rb | ||
| custom_emoji_filter.rb | ||
| domain_block.rb | ||
| email_domain_block.rb | ||
| export.rb | ||
| favourite.rb | ||
| feed.rb | ||
| follow.rb | ||
| follow_request.rb | ||
| import.rb | ||
| instance.rb | ||
| instance_filter.rb | ||
| keyword_mute.rb | ||
| media_attachment.rb | ||
| mention.rb | ||
| mute.rb | ||
| notification.rb | ||
| preview_card.rb | ||
| remote_follow.rb | ||
| remote_profile.rb | ||
| report.rb | ||
| report_filter.rb | ||
| search.rb | ||
| session_activation.rb | ||
| setting.rb | ||
| site_upload.rb | ||
| status.rb | ||
| status_pin.rb | ||
| stream_entry.rb | ||
| subscription.rb | ||
| tag.rb | ||
| user.rb | ||
| web.rb | ||