- Patch #715108 by Damien Tournoud, Berdir, Josh Waihi, Crell, chx, justinrandell: Make merge queries more consistent and robust.

1 files changed, 9 insertions, 111 deletions

diff --git a/includes/database/mysql/query.inc b/includes/database/mysql/query.inc
index 63c0fe8e7..584a4a473 100644
--- a/includes/database/mysql/query.inc
+++ b/includes/database/mysql/query.inc
@@ -87,121 +87,19 @@ class InsertQuery_mysql extends InsertQuery {
   }
 }
 
-class MergeQuery_mysql extends MergeQuery {
-
-  public function execute() {
-
-    // A merge query without any key field is invalid.
-    if (count($this->keyFields) == 0) {
-      throw new InvalidMergeQueryException("You need to specify key fields before executing a merge query");
-    }
-
-    // Set defaults.
-    if ($this->updateFields) {
-      $update_fields = $this->updateFields;
-    }
-    else {
-      // When update fields are derived from insert fields, we don't need
-      // placeholders since we can tell MySQL to reuse insert supplied
-      // values using the VALUES(col_name) function.
-      $update_fields = array();
-    }
-
-    $insert_fields = $this->insertFields + $this->keyFields;
-
-    $max_placeholder = 0;
-    $values = array();
-    // We assume that the order here is the same as in __toString(). If that's
-    // not the case, then we have serious problems.
-    foreach ($insert_fields as $value) {
-      $values[':db_insert_placeholder_' . $max_placeholder++] = $value;
-    }
-
-    // Expressions take priority over literal fields, so we process those first
-    // and remove any literal fields that conflict.
-    foreach ($this->expressionFields as $field => $data) {
-      if (!empty($data['arguments'])) {
-        $values += $data['arguments'];
-      }
-      unset($update_fields[$field]);
-    }
-
-    // Because we filter $fields the same way here and in __toString(), the
-    // placeholders will all match up properly.
-    $max_placeholder = 0;
-    foreach ($update_fields as $field => $value) {
-      $values[':db_update_placeholder_' . ($max_placeholder++)] = $value;
-    }
-
-
-    // MySQL's INSERT ... ON DUPLICATE KEY UPDATE queries return 1
-    // (MergeQuery::STATUS_INSERT) for an INSERT operation or 2
-    // (MergeQuery::STATUS_UPDATE) for an UPDATE operation.
-    //
-    // @link http ://dev.mysql.com/doc/refman/5.0/en/mysql-affected-rows.html
-    $this->queryOptions['return'] = Database::RETURN_AFFECTED;
-    return $this->connection->query((string) $this, $values, $this->queryOptions);
-  }
-
-
+class TruncateQuery_mysql extends TruncateQuery {
   public function __toString() {
-    // Create a comments string to prepend to the query.
-    $comments = (!empty($this->comments)) ? '/* ' . implode('; ', $this->comments) . ' */ ' : '';
-
-    // Set defaults.
-    if ($this->updateFields) {
-      $update_fields = $this->updateFields;
+    // TRUNCATE is actually a DDL statement on MySQL, and DDL statements are
+    // not transactional, and result in an implicit COMMIT. When we are in a
+    // transaction, fallback to the slower, but transactional, DELETE.
+    if ($this->connection->inTransaction()) {
+      // Create a comments string to prepend to the query.
+      $comments = (!empty($this->comments)) ? '/* ' . implode('; ', $this->comments) . ' */ ' : '';
+      return $comments . 'DELETE FROM {' . $this->connection->escapeTable($this->table) . '}';
     }
     else {
-      $update_fields = $this->insertFields;
-      // If there are no exclude fields, this is a no-op.
-      foreach ($this->excludeFields as $exclude_field) {
-        unset($update_fields[$exclude_field]);
-      }
-    }
-
-    // If the merge query has no fields to update, add the first key as an
-    // update field so the query will not fail if a duplicate key is found.
-    if (!$update_fields && !$this->expressionFields) {
-      $update_fields = array_slice($this->keyFields, 0, 1, TRUE);
-    }
-
-    $insert_fields = $this->insertFields + $this->keyFields;
-
-    $query = $comments . 'INSERT INTO {' . $this->table . '} (' . implode(', ', array_keys($insert_fields)) . ') VALUES ';
-
-    $max_placeholder = 0;
-    $values = array();
-    // We don't need the $field, but this is a convenient way to count.
-    foreach ($insert_fields as $field) {
-      $values[] = ':db_insert_placeholder_' . $max_placeholder++;
+      return parent::__toString();
     }
-
-    $query .= '(' . implode(', ', $values) . ') ON DUPLICATE KEY UPDATE ';
-
-    // Expressions take priority over literal fields, so we process those first
-    // and remove any literal fields that conflict.
-    $max_placeholder = 0;
-    $update = array();
-    foreach ($this->expressionFields as $field => $data) {
-      $update[] = $field . '=' . $data['expression'];
-      unset($update_fields[$field]);
-    }
-
-    // Build update fields clauses based on caller supplied list, or derived
-    // from insert supplied values using the VALUES(col_name) function.
-    foreach ($update_fields as $field => $value) {
-      if ($this->updateFields) {
-        $update[] = ($field . '=:db_update_placeholder_' . $max_placeholder++);
-      }
-      else {
-        $update[] = ($field . '=VALUES(' . $field . ')');
-      }
-    }
-
-    $query .= implode(', ', $update);
-
-    return $query;
   }
 }