point index_trgm_users_name_active_only at the right column

fixes CNVS-30740

Change-Id: I2463a0add13cead70f89524132b6b6eac640e945
Reviewed-on: https://gerrit.instructure.com/86769
Reviewed-by: Cody Cutrer <cody@instructure.com>
Product-Review: Alex Boyd <aboyd@instructure.com>
QA-Review: Alex Boyd <aboyd@instructure.com>
Tested-by: Jenkins

db/migrate/20160730111234_add_user_active_only_gist_indexes.rb

@@ -1,17 +1,19 @@
 class AddUserActiveOnlyGistIndexes < ActiveRecord::Migration
   disable_ddl_transaction!
-  tag :predeploy
+  tag :postdeploy
 
   def self.up
     if schema = connection.extension_installed?(:pg_trgm)
       concurrently = " CONCURRENTLY" if connection.open_transactions == 0
-      execute("CREATE INDEX#{concurrently} index_trgm_users_name_active_only ON #{User.quoted_table_name} USING gist(LOWER(short_name) #{schema}.gist_trgm_ops) WHERE workflow_state IN ('registered', 'pre_registered')")
+      # next line indexes the wrong column, so it's nuked and another migration adds the right one and fixes up
+      # people who already ran this migration
+      # execute("CREATE INDEX#{concurrently} index_trgm_users_name_active_only ON #{User.quoted_table_name} USING gist(LOWER(short_name) #{schema}.gist_trgm_ops) WHERE workflow_state IN ('registered', 'pre_registered')")
       execute("CREATE INDEX#{concurrently} index_trgm_users_short_name_active_only ON #{User.quoted_table_name} USING gist(LOWER(short_name) #{schema}.gist_trgm_ops) WHERE workflow_state IN ('registered', 'pre_registered')")
     end
   end
 
   def self.down
-    remove_index :users, name: 'index_trgm_users_name_active_only'
+    remove_index :users, name: 'index_trgm_users_name_active_only' if index_exists?(:users, 'index_trgm_users_name_active_only')
     remove_index :users, name: 'index_trgm_users_short_name_active_only'
   end
 end

db/migrate/20160803022917_fix_user_active_only_gist_indexes.rb

@@ -0,0 +1,22 @@
+class FixUserActiveOnlyGistIndexes < ActiveRecord::Migration
+  disable_ddl_transaction!
+  tag :postdeploy
+
+  def self.up
+    if schema = connection.extension_installed?(:pg_trgm)
+      remove_index :users, name: 'index_trgm_users_name_active_only' if index_exists?(:users, 'index_trgm_users_name_active_only')
+
+      concurrently = " CONCURRENTLY" if connection.open_transactions == 0
+      execute("CREATE INDEX#{concurrently} index_trgm_users_name_active_only ON #{User.quoted_table_name} USING gist(LOWER(name) #{schema}.gist_trgm_ops) WHERE workflow_state IN ('registered', 'pre_registered')")
+    end
+  end
+
+  def self.down
+    if schema = connection.extension_installed?(:pg_trgm)
+      remove_index :users, name: 'index_trgm_users_name_active_only' if index_exists?(:users, 'index_trgm_users_name_active_only')
+
+      concurrently = " CONCURRENTLY" if connection.open_transactions == 0
+      execute("CREATE INDEX#{concurrently} index_trgm_users_name_active_only ON #{User.quoted_table_name} USING gist(LOWER(short_name) #{schema}.gist_trgm_ops) WHERE workflow_state IN ('registered', 'pre_registered')")
+    end
+  end
+end