diff --git a/resources/sql/autopatches/20180828.phriction.06.c.documentid.php b/resources/sql/autopatches/20180828.phriction.06.c.documentid.php
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20180828.phriction.06.c.documentid.php
@@ -0,0 +1,20 @@
+<?php
+
+// See T13193. We're about to drop the "documentID" column, which is part of
+// a UNIQUE KEY. In MariaDB, we must first drop the "documentID" key or we get
+// into deep trouble.
+
+// There's no "IF EXISTS" modifier for "ALTER TABLE" so run this as a PHP patch
+// instead of an SQL patch.
+
+$table = new PhrictionContent();
+$conn = $table->establishConnection('w');
+
+try {
+  queryfx(
+    $conn,
+    'ALTER TABLE %T DROP KEY documentID',
+    $table->getTableName());
+} catch (AphrontQueryException $ex) {
+  // Ignore.
+}
diff --git a/resources/sql/autopatches/20180828.phriction.07.documentkey.sql b/resources/sql/autopatches/20180828.phriction.07.documentkey.sql
new file mode 100644
--- /dev/null
+++ b/resources/sql/autopatches/20180828.phriction.07.documentkey.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_phriction.phriction_content
+  ADD UNIQUE KEY `key_version` (documentPHID, version);
diff --git a/src/applications/phriction/storage/PhrictionContent.php b/src/applications/phriction/storage/PhrictionContent.php
--- a/src/applications/phriction/storage/PhrictionContent.php
+++ b/src/applications/phriction/storage/PhrictionContent.php
@@ -34,7 +34,7 @@
         'description' => 'text',
       ),
       self::CONFIG_KEY_SCHEMA => array(
-        'documentID' => array(
+        'key_version' => array(
           'columns' => array('documentPHID', 'version'),
           'unique' => true,
         ),