diff --git a/lib/Db/CacheActorsRequest.php b/lib/Db/CacheActorsRequest.php
index 5d703098..e69afbc1 100644
--- a/lib/Db/CacheActorsRequest.php
+++ b/lib/Db/CacheActorsRequest.php
@@ -64,6 +64,11 @@ class CacheActorsRequest extends CacheActorsRequestBuilder {
 	 * @param Person $actor
 	 */
 	public function save(Person $actor) {
+		$source = $actor->getSource();
+		if (strlen($source) >= CoreRequestBuilder::SOURCE_LENGTH) {
+			$source = 'too_big';
+		}
+
 		$qb = $this->getCacheActorsInsertSql();
 		$qb->setValue('id', $qb->createNamedParameter($actor->getId()))
 		   ->setValue('account', $qb->createNamedParameter($actor->getAccount()))
@@ -82,7 +87,7 @@ class CacheActorsRequest extends CacheActorsRequestBuilder {
 		   ->setValue('name', $qb->createNamedParameter($actor->getName()))
 		   ->setValue('summary', $qb->createNamedParameter($actor->getSummary()))
 		   ->setValue('public_key', $qb->createNamedParameter($actor->getPublicKey()))
-		   ->setValue('source', $qb->createNamedParameter($actor->getSource()))
+		   ->setValue('source', $qb->createNamedParameter($source))
 		   ->setValue('details', $qb->createNamedParameter(json_encode($actor->getDetails())))
 		   ->setValue(
 			   'creation',
diff --git a/lib/Db/CoreRequestBuilder.php b/lib/Db/CoreRequestBuilder.php
index 7176ed8c..8f594ddd 100644
--- a/lib/Db/CoreRequestBuilder.php
+++ b/lib/Db/CoreRequestBuilder.php
@@ -64,6 +64,9 @@ class CoreRequestBuilder {
 	const TABLE_CACHE_DOCUMENTS = 'social_cache_documents';
 
 
+	const SOURCE_LENGTH = 10000;
+
+
 	/** @var IDBConnection */
 	protected $dbConnection;
 
diff --git a/lib/Db/NotesRequest.php b/lib/Db/NotesRequest.php
index 891c7f91..fdd1313b 100644
--- a/lib/Db/NotesRequest.php
+++ b/lib/Db/NotesRequest.php
@@ -66,6 +66,11 @@ class NotesRequest extends NotesRequestBuilder {
 		$dTime = new DateTime();
 		$dTime->setTimestamp($note->getPublishedTime());
 
+		$source = $note->getSource();
+		if (strlen($source) >= CoreRequestBuilder::SOURCE_LENGTH) {
+			$source = 'too_big';
+		}
+
 		$qb = $this->getNotesInsertSql();
 		$qb->setValue('id', $qb->createNamedParameter($note->getId()))
 		   ->setValue('type', $qb->createNamedParameter($note->getType()))
@@ -93,7 +98,7 @@ class NotesRequest extends NotesRequestBuilder {
 		   )
 		   ->setValue('attributed_to', $qb->createNamedParameter($note->getAttributedTo()))
 		   ->setValue('in_reply_to', $qb->createNamedParameter($note->getInReplyTo()))
-		   ->setValue('source', $qb->createNamedParameter($note->getSource()))
+		   ->setValue('source', $qb->createNamedParameter($source))
 		   ->setValue(
 			   'instances', $qb->createNamedParameter(
 			   json_encode($note->getInstancePaths(), JSON_UNESCAPED_SLASHES)
diff --git a/lib/Migration/Version0001Date20181208185242.php b/lib/Migration/Version0001Date20181208185242.php
new file mode 100644
index 00000000..3194f2ee
--- /dev/null
+++ b/lib/Migration/Version0001Date20181208185242.php
@@ -0,0 +1,88 @@
+<?php
+declare(strict_types=1);
+
+
+/**
+ * Nextcloud - Social Support
+ *
+ * This file is licensed under the Affero General Public License version 3 or
+ * later. See the COPYING file.
+ *
+ * @author Maxence Lange <maxence@artificial-owl.com>
+ * @copyright 2018, Maxence Lange <maxence@artificial-owl.com>
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+
+namespace OCA\Social\Migration;
+
+
+use Closure;
+use OCA\Social\Db\CoreRequestBuilder;
+use OCP\DB\ISchemaWrapper;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+
+/**
+ * Class Version0001Date20181208185242
+ *
+ * @package OCA\Social\Migration
+ */
+class Version0001Date20181208185242 extends SimpleMigrationStep {
+
+
+	/**
+	 * @param IOutput $output
+	 * @param Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+	 * @param array $options
+	 *
+	 * @return ISchemaWrapper
+	 * @throws \Doctrine\DBAL\Schema\SchemaException
+	 */
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options
+	): ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		$table = $schema->getTable(CoreRequestBuilder::TABLE_CACHE_ACTORS);
+		$table->changeColumn(
+			'source', [
+						'notnull' => true,
+						'length'  => CoreRequestBuilder::SOURCE_LENGTH,
+					]
+		);
+
+		$table = $schema->getTable(CoreRequestBuilder::TABLE_SERVER_NOTES);
+		$table->changeColumn(
+			'source', [
+						'notnull' => true,
+						'length'  => CoreRequestBuilder::SOURCE_LENGTH,
+					]
+		);
+
+		$table = $schema->getTable(CoreRequestBuilder::TABLE_REQUEST_QUEUE);
+		$table->changeColumn(
+			'activity', [
+						  'notnull' => true,
+						  'length'  => CoreRequestBuilder::SOURCE_LENGTH,
+					  ]
+		);
+
+		return $schema;
+	}
+}