diff --git a/autotests/libs/itemappendtest.cpp b/autotests/libs/itemappendtest.cpp
--- a/autotests/libs/itemappendtest.cpp
+++ b/autotests/libs/itemappendtest.cpp
@@ -55,6 +55,7 @@
     QTest::newRow("whitespace") << QStringLiteral("remote id");
     QTest::newRow("quotes") << QStringLiteral("\"remote\" id");
     QTest::newRow("brackets") << QStringLiteral("[remote id]");
+    QTest::newRow("RID length limit") << QStringLiteral("a").repeated(1024);
 }
 
 void ItemAppendTest::testItemAppend()
@@ -399,3 +400,4 @@
     QVERIFY(file.exists());
     QVERIFY(file.remove());
 }
+
diff --git a/src/server/storage/akonadidb.xml b/src/server/storage/akonadidb.xml
--- a/src/server/storage/akonadidb.xml
+++ b/src/server/storage/akonadidb.xml
@@ -67,7 +67,7 @@
     <comment>Contains the schema version of the database.</comment>
     <column name="version" type="int" default="0" allowNull="false"/>
     <column name="generation" type="int" default="0" allowNull="false" />
-    <data columns="version" values="40"/>
+    <data columns="version" values="41"/>
   </table>
 
   <table name="Resource">
@@ -126,7 +126,7 @@
   <table name="PimItem">
     <column name="id" type="qint64" allowNull="false" isAutoIncrement="true" isPrimaryKey="true"/>
     <column name="rev" type="int" default="0" allowNull="false"/>
-    <column name="remoteId" type="QString"/>
+    <column name="remoteId" type="QString" size="1024"/>
     <column name="remoteRevision" type="QString"/>
     <column name="gid" type="QString"/>
     <column name="collectionId" type="qint64" refTable="Collection" refColumn="id"/>
diff --git a/src/server/storage/dbinitializer_p.cpp b/src/server/storage/dbinitializer_p.cpp
--- a/src/server/storage/dbinitializer_p.cpp
+++ b/src/server/storage/dbinitializer_p.cpp
@@ -19,7 +19,9 @@
  ***************************************************************************/
 
 #include "storage/dbinitializer_p.h"
+#include <shared/akranges.h>
 
+using namespace Akonadi;
 using namespace Akonadi::Server;
 
 //BEGIN MySQL
@@ -64,7 +66,10 @@
     }
     columns << references;
 
-    const QString tableProperties = QStringLiteral(" COLLATE=utf8_general_ci DEFAULT CHARSET=utf8");
+    QString tableProperties = QStringLiteral(" COLLATE=utf8_general_ci DEFAULT CHARSET=utf8");
+    if (tableDescription.columns | any([](const auto &col) { return col.type == QLatin1String("QString") && col.size > 255; })) {
+        tableProperties += QStringLiteral(" ROW_FORMAT=DYNAMIC");
+    }
 
     return QStringLiteral("CREATE TABLE %1 (%2) %3").arg(tableDescription.name, columns.join(QStringLiteral(", ")), tableProperties);
 }
diff --git a/src/server/storage/dbupdate.xml b/src/server/storage/dbupdate.xml
--- a/src/server/storage/dbupdate.xml
+++ b/src/server/storage/dbupdate.xml
@@ -346,4 +346,10 @@
     <!-- FIXME: SQLite doesn't allow for a straight-forward migration, but this has never reached
          a release, so we are mostly OK here. //-->
   </update>
+
+  <update version="41" abortOnFailure="true">
+    <!-- Allow for up to 1024-character long indexes, used for PimItem.remoteId //-->
+    <raw-sql backends="mysql">ALTER TABLE PimItemTable ROW_FORMAT=DYNAMIC</raw-sql>
+    <raw-sql backends="mysql">ALTER TABLE PimItemTable MODIFY COLUMN remoteId VARBINARY(1024)</raw-sql>
+  </update>
 </updates>
diff --git a/src/server/storage/mysql-global-mobile.conf b/src/server/storage/mysql-global-mobile.conf
--- a/src/server/storage/mysql-global-mobile.conf
+++ b/src/server/storage/mysql-global-mobile.conf
@@ -58,6 +58,9 @@
 # Size of each log file in a log group (default:5M) larger means less I/O but more time for recovery.
 innodb_log_file_size=2M
 
+# Enable varchar index keys up to 3072 bytes (1024 characters), compared to 768 bytes (255 characters) with normal settings
+innodb_large_prefix=1
+
 # # error log file name, relative to datadir (default:hostname.err)
 log_error=mysql.err