Make post guids unique

db/migrate/20110317222802_guid_is_unique.rb

@@ -0,0 +1,36 @@
+class GuidIsUnique < ActiveRecord::Migration
+  def self.consolidate_post(guid)
+    post_ids = execute("select posts.id from posts where posts.guid = #{guid}").to_a.flatten!
+    keep_id = post_ids.pop
+    execute("UPDATE comments
+            SET comments.post_id = #{keep_id}
+            WHERE comments.post_id IN (#{post_ids.join(',')})")
+
+    execute("UPDATE posts
+            SET posts.status_message_id = #{keep_id}
+            WHERE posts.status_message_id IN (#{post_ids.join(',')})")
+
+    execute("DELETE post_visibilities WHERE post_visibilities.post_id IN (#{post_ids.join(',')})")
+    execute("DELETE mentions WHERE mentions.post_id IN (#{post_ids.join(',')})")
+    execute("DELETE posts WHERE posts.id IN (#{post_ids.join(',')})")
+  end
+  def self.up
+    sql = <<-SQL
+    SELECT posts.guid FROM posts
+      GROUP BY posts.guid
+        HAVING COUNT(*)>1;
+    SQL
+    duplicated_guids = execute(sql).to_a.flatten!
+
+    duplicated_guids.each do |guid|
+      consolidate_post(guid)
+    end if duplicated_guids
+    remove_index :posts, :guid
+    add_index :posts, :guid, :unique => true
+  end
+
+  def self.down
+    remove_index :posts, :column => :guid
+    add_index :posts, :guid
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20110314043119) do
+ActiveRecord::Schema.define(:version => 20110317222802) do
 
   create_table "aspect_memberships", :force => true do |t|
     t.integer  "aspect_id",  :null => false
@@ -213,7 +213,7 @@ ActiveRecord::Schema.define(:version => 20110314043119) do
   end
 
   add_index "posts", ["author_id"], :name => "index_posts_on_person_id"
-  add_index "posts", ["guid"], :name => "index_posts_on_guid"
+  add_index "posts", ["guid"], :name => "index_posts_on_guid", :unique => true
   add_index "posts", ["mongo_id"], :name => "index_posts_on_mongo_id"
   add_index "posts", ["status_message_id", "pending"], :name => "index_posts_on_status_message_id_and_pending"
   add_index "posts", ["status_message_id"], :name => "index_posts_on_status_message_id"