diff --git a/question/engine/bank.php b/question/engine/bank.php
index 5ccc2c19d20..ad4e4930ae1 100644
--- a/question/engine/bank.php
+++ b/question/engine/bank.php
@@ -42,6 +42,8 @@ require_once(dirname(__FILE__) . '/../type/questiontypebase.php');
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 abstract class question_bank {
+    const MAX_SUMMARY_LENGTH = 65000;
+
     /** @var array question type name => question_type subclass. */
     private static $questiontypes = array();
 
diff --git a/question/engine/datalib.php b/question/engine/datalib.php
index 2f41b12d7ff..9d94731f57a 100644
--- a/question/engine/datalib.php
+++ b/question/engine/datalib.php
@@ -89,6 +89,11 @@ class question_engine_data_mapper {
         $record->minfraction = $qa->get_min_fraction();
         $record->flagged = $qa->is_flagged();
         $record->questionsummary = $qa->get_question_summary();
+        if (textlib::strlen($record->questionsummary) > question_bank::MAX_SUMMARY_LENGTH) {
+            // It seems some people write very long quesions! MDL-30760
+            $record->questionsummary = textlib::substr($record->questionsummary,
+                    0, question_bank::MAX_SUMMARY_LENGTH - 3) . '...';
+        }
         $record->rightanswer = $qa->get_right_answer_summary();
         $record->responsesummary = $qa->get_response_summary();
         $record->timemodified = time();
diff --git a/question/engine/upgrade/upgradelib.php b/question/engine/upgrade/upgradelib.php
index 6f0aac88c08..7e682f0ed9c 100644
--- a/question/engine/upgrade/upgradelib.php
+++ b/question/engine/upgrade/upgradelib.php
@@ -245,6 +245,11 @@ class question_engine_attempt_upgrader {
             $qa = $qas[$questionid];
             $qa->questionusageid = $attempt->uniqueid;
             $qa->slot = $i;
+            if (textlib::strlen($qa->questionsummary) > question_bank::MAX_SUMMARY_LENGTH) {
+                // It seems some people write very long quesions! MDL-30760
+                $qa->questionsummary = textlib::substr($qa->questionsummary,
+                        0, question_bank::MAX_SUMMARY_LENGTH - 3) . '...';
+            }
             $this->insert_record('question_attempts', $qa);
             $layout[$questionkeys[$questionid]] = $qa->slot;
 
diff --git a/question/type/multianswer/questiontype.php b/question/type/multianswer/questiontype.php
index 32f36c1ee77..c9cb5df8363 100644
--- a/question/type/multianswer/questiontype.php
+++ b/question/type/multianswer/questiontype.php
@@ -404,7 +404,7 @@ function qtype_multianswer_extract_question($text) {
                     && preg_match('~'.NUMERICAL_ALTERNATIVE_REGEX.'~',
                             $altregs[ANSWER_ALTERNATIVE_REGEX_ANSWER], $numregs)) {
                 $wrapped->answer[] = $numregs[NUMERICAL_CORRECT_ANSWER];
-                if ($numregs[NUMERICAL_ABS_ERROR_MARGIN]) {
+                if (array_key_exists(NUMERICAL_ABS_ERROR_MARGIN, $numregs)) {
                     $wrapped->tolerance["$answerindex"] =
                     $numregs[NUMERICAL_ABS_ERROR_MARGIN];
                 } else {