diff --git a/app/models/site_setting.rb b/app/models/site_setting.rb
index 92252160a10..ee20d17616a 100644
--- a/app/models/site_setting.rb
+++ b/app/models/site_setting.rb
@@ -153,7 +153,7 @@ class SiteSetting < ActiveRecord::Base
 
       # cf. http://docs.aws.amazon.com/general/latest/gr/rande.html#s3_region
       if SiteSetting.s3_endpoint == "https://s3.amazonaws.com"
-        if SiteSetting.Upload.s3_region == 'cn-north-1' || SiteSetting.Upload.s3_region == 'cn-northwest-1'
+        if SiteSetting.Upload.s3_region.start_with?("cn-")
           "//#{bucket}.s3.#{SiteSetting.Upload.s3_region}.amazonaws.com.cn"
         else
           "//#{bucket}.s3.dualstack.#{SiteSetting.Upload.s3_region}.amazonaws.com"
diff --git a/lib/db_helper.rb b/lib/db_helper.rb
index 04c9f8d3fb3..19cdfe5d814 100644
--- a/lib/db_helper.rb
+++ b/lib/db_helper.rb
@@ -1,60 +1,91 @@
 class DbHelper
 
-  REMAP_SQL ||= "
+  REMAP_SQL ||= <<~SQL
     SELECT table_name, column_name
       FROM information_schema.columns
      WHERE table_schema = 'public'
        AND is_updatable = 'YES'
        AND (data_type LIKE 'char%' OR data_type LIKE 'text%')
-  ORDER BY table_name, column_name"
+  ORDER BY table_name, column_name
+  SQL
 
-  def self.remap(from, to, anchor_left: false, anchor_right: false, exclude_tables: [])
-    results = DB.query(REMAP_SQL).to_a
+  def self.remap(from, to, anchor_left: false, anchor_right: false, excluded_tables: [])
     like = "#{anchor_left ? '' : "%"}#{from}#{anchor_right ? '' : "%"}"
+    text_columns = Hash.new { |h, k| h[k] = [] }
 
-    remappable_columns = {}
-
-    results.each do |result|
-      remappable_columns[result.table_name] ||= []
-      remappable_columns[result.table_name] << result.column_name
+    DB.query(REMAP_SQL).each do |r|
+      text_columns[r.table_name] << r.column_name
     end
 
-    exclude_tables = exclude_tables.map(&:to_s)
+    text_columns.each do |table, columns|
+      next if excluded_tables.include?(table)
 
-    remappable_columns.each do |table_name, column_names|
-      next if exclude_tables.include?(table_name)
-      set_clause = column_names.map do |column_name|
-        "#{column_name} = REPLACE(#{column_name}, :from, :to)"
+      set = columns.map do |column|
+        "#{column} = REPLACE(#{column}, :from, :to)"
       end.join(", ")
 
-      where_clause = column_names.map do |column_name|
-        "#{column_name} LIKE :like"
+      where = columns.map do |column|
+        "#{column} IS NOT NULL AND #{column} LIKE :like"
       end.join(" OR ")
 
       DB.exec(<<~SQL, from: from, to: to, like: like)
-        UPDATE #{table_name}
-        SET #{set_clause}
-        WHERE #{where_clause}
+        UPDATE #{table}
+           SET #{set}
+         WHERE #{where}
       SQL
     end
 
     SiteSetting.refresh!
   end
 
-  def self.find(needle, anchor_left = false, anchor_right = false)
-    connection = ActiveRecord::Base.connection.raw_connection
-    text_columns = connection.async_exec(REMAP_SQL).to_a
-    args = ["#{anchor_left ? '' : "%"}#{needle}#{anchor_right ? '' : "%"}"]
-    found = {}
+  def self.regexp_replace(pattern, replacement, flags: "gi", match: "~*", excluded_tables: [])
+    text_columns = Hash.new { |h, k| h[k] = [] }
 
-    text_columns.each do |rc|
-      table_name = rc["table_name"]
-      column_name = rc["column_name"]
-      result = connection.async_exec("SELECT #{column_name} FROM #{table_name} WHERE #{column_name} LIKE $1", args) rescue nil
-      if result&.ntuples > 0
-        found["#{table_name}.#{column_name}"] = result.map { |r| r[column_name] }
+    DB.query(REMAP_SQL).each do |r|
+      text_columns[r.table_name] << r.column_name
+    end
+
+    text_columns.each do |table, columns|
+      next if excluded_tables.include?(table)
+
+      set = columns.map do |column|
+        "#{column} = REGEXP_REPLACE(#{column}, :pattern, :replacement, :flags)"
+      end.join(", ")
+
+      where = columns.map do |column|
+        "#{column} IS NOT NULL AND #{column} #{match} :pattern"
+      end.join(" OR ")
+
+      puts pattern, replacement, flags, match
+
+      DB.exec(<<~SQL, pattern: pattern, replacement: replacement, flags: flags, match: match)
+        UPDATE #{table}
+           SET #{set}
+         WHERE #{where}
+      SQL
+    end
+
+    SiteSetting.refresh!
+  end
+
+  def self.find(needle, anchor_left: false, anchor_right: false, excluded_tables: [])
+    found = {}
+    like = "#{anchor_left ? '' : "%"}#{needle}#{anchor_right ? '' : "%"}"
+
+    DB.query(REMAP_SQL).each do |r|
+      next if excluded_tables.include?(r.table_name)
+
+      rows = DB.query(<<~SQL, like: like)
+        SELECT #{r.column_name}
+          FROM #{r.table_name}
+         WHERE #{r.column_name} LIKE :like
+      SQL
+
+      if rows.size > 0
+        found["#{r.table_name}.#{r.column_name}"] = rows.map { |row| row.send(r.column_name) }
       end
     end
+
     found
   end
 
diff --git a/lib/file_store/base_store.rb b/lib/file_store/base_store.rb
index bdc48562448..9043205c88b 100644
--- a/lib/file_store/base_store.rb
+++ b/lib/file_store/base_store.rb
@@ -98,7 +98,7 @@ module FileStore
 
     def get_path_for(type, id, sha, extension)
       depth = get_depth_for(id)
-      tree = File.join(*sha[0, depth].split(""), "")
+      tree = File.join(*sha[0, depth].chars, "")
       "#{type}/#{depth + 1}X/#{tree}#{sha}#{extension}"
     end
 
@@ -107,8 +107,7 @@ module FileStore
         if upload.extension
           ".#{upload.extension}"
         else
-          # Maintain backward compatibility before Jobs::MigrateUploadExtensions
-          # runs
+          # Maintain backward compatibility before Jobs::MigrateUploadExtensions runs
           File.extname(upload.original_filename)
         end
 
diff --git a/lib/s3_helper.rb b/lib/s3_helper.rb
index c3dad0694c0..708c2321334 100644
--- a/lib/s3_helper.rb
+++ b/lib/s3_helper.rb
@@ -24,8 +24,7 @@ class S3Helper
 
   def upload(file, path, options = {})
     path = get_path_for_s3_upload(path)
-    obj = s3_bucket.object(path)
-    obj.upload_file(file, options)
+    s3_bucket.object(path).upload_file(file, options)
     path
   end
 
@@ -93,7 +92,6 @@ class S3Helper
   end
 
   def update_lifecycle(id, days, prefix: nil, tag: nil)
-
     filter = {}
 
     if prefix
@@ -171,14 +169,15 @@ class S3Helper
   end
 
   def object(path)
-    path = get_path_for_s3_upload(path)
-    s3_bucket.object(path)
+    s3_bucket.object(get_path_for_s3_upload(path))
   end
 
   def self.s3_options(obj)
-    opts = { region: obj.s3_region,
-             endpoint: SiteSetting.s3_endpoint,
-             force_path_style: SiteSetting.s3_force_path_style }
+    opts = {
+      region: obj.s3_region,
+      endpoint: SiteSetting.s3_endpoint,
+      force_path_style: SiteSetting.s3_force_path_style
+    }
 
     unless obj.s3_use_iam_profile
       opts[:access_key_id] = obj.s3_access_key_id
diff --git a/lib/tasks/uploads.rake b/lib/tasks/uploads.rake
index cf175150227..b722d1c755f 100644
--- a/lib/tasks/uploads.rake
+++ b/lib/tasks/uploads.rake
@@ -203,9 +203,6 @@ end
 ################################################################################
 
 task "uploads:migrate_to_s3" => :environment do
-  require "file_store/s3_store"
-  require "file_store/local_store"
-
   ENV["RAILS_DB"] ? migrate_to_s3 : migrate_to_s3_all_sites
 end
 
@@ -214,93 +211,180 @@ def migrate_to_s3_all_sites
 end
 
 def migrate_to_s3
-  # make sure s3 is enabled
-  if !SiteSetting.Upload.enable_s3_uploads
-    puts "You must enable s3 uploads before running that task"
-    return
-  end
-
   db = RailsMultisite::ConnectionManagement.current_db
 
-  puts "Migrating uploads to S3 (#{SiteSetting.Upload.s3_upload_bucket}) for '#{db}'..."
+  dry_run = !!ENV["DRY_RUN"]
 
-  # will throw an exception if the bucket is missing
-  s3 = FileStore::S3Store.new
-  local = FileStore::LocalStore.new
+  puts "*" * 30 + " DRY RUN " + "*" * 30 if dry_run
+  puts "Migrating uploads to S3 for '#{db}'..."
 
-  exclude_tables = %i{
-    incoming_emails
-    stylesheet_cache
-    search_logs
-    post_search_data
-    notifications
-    email_logs
-  }
+  if Upload.where("url NOT LIKE '//%' AND url NOT LIKE '/uploads/#{db}/original/_X/%'").exists?
+    puts <<~TEXT
+      Some uploads were not migrated to the new scheme. Please run these commands in the rails console
 
-  # Migrate all uploads
-  file_uploads = Upload.where.not(sha1: nil).where("url NOT LIKE '#{s3.absolute_base_url}%'")
-  image_uploads = file_uploads.where("lower(extension) NOT IN (?)", FileHelper.supported_images.to_a)
+      SiteSetting.migrate_to_new_scheme = true
+      Jobs::MigrateUploadScheme.new.execute(nil)
+    TEXT
+    exit 1
+  end
 
-  [image_uploads, file_uploads].each do |uploads|
-    uploads.find_in_batches(batch_size: 100) do |batch|
-      batch.each do |upload|
-        now = Process.clock_gettime(Process::CLOCK_MONOTONIC)
-        # remove invalid uploads
-        if upload.url.blank?
-          upload.destroy!
-          next
-        end
-        # store the old url
-        from = upload.url
-        # retrieve the path to the local file
-        path = local.path_for(upload)
-        # make sure the file exists locally
-        if !path || !File.exists?(path)
-          puts "#{from} does not exist locally"
-          next
-        end
+  unless GlobalSetting.use_s3?
+    puts <<~TEXT
+      Please provide the following environment variables
+        - DISCOURSE_S3_BUCKET
+        - DISCOURSE_S3_REGION
+        - DISCOURSE_S3_ACCESS_KEY_ID
+        - DISCOURSE_S3_SECRET_ACCESS_KEY
+    TEXT
+    exit 2
+  end
 
-        begin
-          file = File.open(path)
-          content_type = `file --mime-type -b #{path}`.strip
-          to = s3.store_upload(file, upload, content_type)
-        rescue => e
-          puts "Encountered an error while migrating #{upload.url}: #{e.class}: #{e.message}"
-          next
-        ensure
-          file&.close
-        end
+  if SiteSetting.Upload.s3_cdn_url.blank?
+    puts "Please provide the 'DISCOURSE_S3_CDN_URL' environment variable"
+    exit 3
+  end
 
-        # remap the URL
-        DbHelper.remap(from, to, exclude_tables: exclude_tables)
-        upload.optimized_images.destroy_all
-        puts "Migrating #{from} --> #{to} took #{Process.clock_gettime(Process::CLOCK_MONOTONIC) - now} seconds"
-      end
+  s3 = Aws::S3::Client.new(
+    region: GlobalSetting.s3_region,
+    access_key_id: GlobalSetting.s3_access_key_id,
+    secret_access_key: GlobalSetting.s3_secret_access_key,
+  )
 
-      [
-        Discourse.asset_host,
-        Discourse.base_url_no_prefix
-      ].each do |from|
-        now = Process.clock_gettime(Process::CLOCK_MONOTONIC)
-        from = "#{from}#{SiteSetting.Upload.s3_base_url}"
-        to = SiteSetting.s3_cdn_url
-        DbHelper.remap(from, to, exclude_tables: exclude_tables)
-        puts "Remapping #{from} --> #{to} took #{Process.clock_gettime(Process::CLOCK_MONOTONIC) - now} seconds"
+  begin
+    s3.head_bucket(bucket: GlobalSetting.s3_bucket)
+  rescue Aws::S3::Errors::NotFound
+    puts "Bucket '#{GlobalSetting.s3_bucket}' not found. Creating it..."
+    s3.create_bucket(bucket: GlobalSetting.s3_bucket) unless dry_run
+  end
+
+  puts "Uploading files to S3..."
+  print " - Listing local files"
+
+  local_files = []
+  IO.popen("cd public && find uploads/#{db}/original -type f").each do |file|
+    local_files << file.chomp
+    putc "." if local_files.size % 1000 == 0
+  end
+
+  puts " => #{local_files.size} files"
+  print " - Listing S3 files"
+
+  s3_objects = []
+  prefix = Rails.configuration.multisite ? "#{db}/original/" : "original/"
+  options = { bucket: GlobalSetting.s3_bucket, prefix: prefix }
+
+  loop do
+    response = s3.list_objects_v2(options)
+    s3_objects.concat(response.contents)
+    putc "."
+    break if response.next_continuation_token.blank?
+    options[:continuation_token] = response.next_continuation_token
+  end
+
+  puts " => #{s3_objects.size} files"
+  print " - Syncing files to S3"
+
+  synced = 0
+  failed = []
+
+  local_files.each do |file|
+    path = File.join("public", file)
+    name = File.basename(path)
+    etag = Digest::MD5.file(path).hexdigest
+
+    if s3_object = s3_objects.find { |obj| file.ends_with?(obj.key) }
+      next if File.size(path) == s3_object.size && s3_object.etag[etag]
+    end
+
+    options = {
+      acl: "public-read",
+      body: File.open(path, "rb"),
+      bucket: GlobalSetting.s3_bucket,
+      content_type: MiniMime.lookup_by_filename(name)&.content_type,
+      key: file[file.index(prefix)..-1],
+    }
+
+    if !FileHelper.is_supported_image?(name)
+      options[:content_disposition] = %Q{attachment; filename="#{name}"}
+    end
+
+    if dry_run
+      puts "#{file} => #{options[:key]}"
+      synced += 1
+    elsif s3.put_object(options).etag[etag]
+      putc "."
+      synced += 1
+    else
+      putc "X"
+      failed << path
+    end
+  end
+
+  puts
+
+  if failed.size > 0
+    puts "Failed to upload #{failed.size} files"
+    puts failed.join("\n")
+  elsif s3_objects.size + synced >= local_files.size
+    puts "Updating the URLs in the database..."
+
+    excluded_tables = %w{
+      email_logs
+      incoming_emails
+      notifications
+      post_search_data
+      search_logs
+      stylesheet_cache
+      user_auth_token_logs
+      user_auth_tokens
+      web_hooks_events
+    }
+
+    from = "/uploads/#{db}/original/(\\dX/(?:[a-f0-9]/)*[a-f0-9]{40}[a-z0-9\\.]*)"
+    to = "#{SiteSetting.Upload.s3_base_url}/#{prefix}\\1"
+
+    if dry_run
+      puts "REPLACING '#{from}' WITH '#{to}'"
+    else
+      DbHelper.regexp_replace(from, to, excluded_tables: excluded_tables)
+    end
+
+    # Uploads that were on base hostname will now be on S3 CDN
+    from = "#{Discourse.base_url}#{SiteSetting.Upload.s3_base_url}"
+    to = SiteSetting.Upload.s3_cdn_url
+
+    if dry_run
+      puts "REMAPPING '#{from}' TO '#{to}'"
+    else
+      DbHelper.remap(from, to, excluded_tables: excluded_tables)
+    end
+
+    if Discourse.asset_host.present?
+      # Uploads that were on local CDN will now be on S3 CDN
+      from = "#{Discourse.asset_host}#{SiteSetting.Upload.s3_base_url}"
+      to = SiteSetting.Upload.s3_cdn_url
+
+      if dry_run
+        puts "REMAPPING '#{from}' TO '#{to}'"
+      else
+        DbHelper.remap(from, to, excluded_tables: excluded_tables)
       end
     end
   end
+
+  puts "Done!"
 end
 
 ################################################################################
-#                                  clean_up                                   #
+#                                  clean_up                                    #
 ################################################################################
 
 task "uploads:clean_up" => :environment do
-  if ENV["RAILS_DB"]
-    clean_up_uploads
-  else
-    RailsMultisite::ConnectionManagement.each_connection { clean_up_uploads }
-  end
+  ENV["RAILS_DB"] ? clean_up_uploads : clean_up_uploads_all_sites
+end
+
+def clean_up_uploads_all_sites
+  RailsMultisite::ConnectionManagement.each_connection { clean_up_uploads }
 end
 
 def clean_up_uploads
diff --git a/spec/lib/db_helper_spec.rb b/spec/lib/db_helper_spec.rb
index e9d796257cf..ef9105ca030 100644
--- a/spec/lib/db_helper_spec.rb
+++ b/spec/lib/db_helper_spec.rb
@@ -36,7 +36,7 @@ RSpec.describe DbHelper do
     it 'allows tables to be excluded from scanning' do
       post = Fabricate(:post, cooked: "test")
 
-      DbHelper.remap("test", "something else", exclude_tables: %w{posts})
+      DbHelper.remap("test", "something else", excluded_tables: %w{posts})
 
       expect(post.reload.cooked).to eq('test')
     end