diff --git a/keyserver/src/fetchers/message-fetchers.js b/keyserver/src/fetchers/message-fetchers.js
--- a/keyserver/src/fetchers/message-fetchers.js
+++ b/keyserver/src/fetchers/message-fetchers.js
@@ -275,24 +275,60 @@
   const truncationStatuses = {};
 
   const viewerID = viewer.id;
-  const query = SQL`
-    SELECT * FROM (
-      SELECT x.id, x.content, x.time, x.type, x.user AS creatorID,
-        x.creation, x.subthread_permissions, x.uploadID, x.uploadType,
-        x.uploadSecret, x.uploadExtra,
-        @num := if(
-          @thread = x.thread,
-          if(@message = x.id, @num, @num + 1),
-          1
-        ) AS number,
-        @message := x.id AS messageID,
-        @thread := x.thread AS threadID
-      FROM (SELECT @num := 0, @thread := '', @message := '') init
-      JOIN (
-        SELECT m.id, m.thread, m.user, m.content, m.time, m.type,
-          m.creation, stm.permissions AS subthread_permissions,
+  const dbType = await getDBType();
+
+  let query;
+  if (dbType === 'mysql5.7') {
+    query = SQL`
+      SELECT * FROM (
+        SELECT x.id, x.content, x.time, x.type, x.user AS creatorID,
+          x.creation, x.subthread_permissions, x.uploadID, x.uploadType,
+          x.uploadSecret, x.uploadExtra,
+          @num := if(
+            @thread = x.thread,
+            if(@message = x.id, @num, @num + 1),
+            1
+          ) AS number,
+          @message := x.id AS messageID,
+          @thread := x.thread AS threadID
+        FROM (SELECT @num := 0, @thread := '', @message := '') init
+        JOIN (
+          SELECT m.id, m.thread, m.user, m.content, m.time, m.type,
+            m.creation, stm.permissions AS subthread_permissions,
+            up.id AS uploadID, up.type AS uploadType, up.secret AS uploadSecret,
+            up.extra AS uploadExtra
+          FROM messages m
+          LEFT JOIN uploads up ON up.container = m.id
+          LEFT JOIN memberships mm
+            ON mm.thread = m.thread AND mm.user = ${viewerID}
+          LEFT JOIN memberships stm ON m.type = ${messageTypes.CREATE_SUB_THREAD}
+            AND stm.thread = m.content AND stm.user = ${viewerID}
+          WHERE JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE AND
+    `;
+    query.append(selectionClause);
+    // - We specify a ridiculously high LIMIT here to force MariaDB to maintain
+    //   the ORDER BY. Otherwise the query optimizer will assume that the order
+    //   doesn't matter because the outer query doesn't have an ORDER BY.
+    // - Setting an ORDER BY on the outer query won't work because our quirky
+    //   counting logic in the SELECT would be executed before the ORDER, on the
+    //   unsorted results from the inner query.
+    // - More details available here:
+    //   https://mariadb.com/kb/en/why-is-order-by-in-a-from-subquery-ignored/
+    query.append(SQL`
+          ORDER BY m.thread, m.time DESC
+          LIMIT 18446744073709551615
+        ) x
+      ) y
+      WHERE y.number <= ${numberPerThread}
+    `);
+  } else {
+    query = SQL`
+      WITH thread_window AS (
+        SELECT m.id, m.thread AS threadID, m.user AS creatorID, m.content,
+          m.time, m.type, m.creation, stm.permissions AS subthread_permissions,
           up.id AS uploadID, up.type AS uploadType, up.secret AS uploadSecret,
-          up.extra AS uploadExtra
+          up.extra AS uploadExtra,
+          ROW_NUMBER() OVER (PARTITION BY threadID ORDER BY time DESC) n
         FROM messages m
         LEFT JOIN uploads up ON up.container = m.id
         LEFT JOIN memberships mm
@@ -300,23 +336,14 @@
         LEFT JOIN memberships stm ON m.type = ${messageTypes.CREATE_SUB_THREAD}
           AND stm.thread = m.content AND stm.user = ${viewerID}
         WHERE JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE AND
-  `;
-  query.append(selectionClause);
-  // - We specify a ridiculously high LIMIT here to force MariaDB to maintain
-  //   the ORDER BY. Otherwise the query optimizer will assume that the order
-  //   doesn't matter because the outer query doesn't have an ORDER BY.
-  // - Setting an ORDER BY on the outer query won't work because our quirky
-  //   counting logic in the SELECT would be executed before the ORDER, on the
-  //   unsorted results from the inner query.
-  // - More details available here:
-  //   https://mariadb.com/kb/en/why-is-order-by-in-a-from-subquery-ignored/
-  query.append(SQL`
-        ORDER BY m.thread, m.time DESC
-        LIMIT 18446744073709551615
-      ) x
-    ) y
-    WHERE y.number <= ${numberPerThread}
-  `);
+    `;
+    query.append(selectionClause);
+    query.append(SQL`
+      )
+      SELECT * FROM thread_window WHERE n <= ${numberPerThread};
+    `);
+  }
+
   const [result] = await dbQuery(query);
   const derivedMessages = await fetchDerivedMessages(result, viewer);
   const messages = await parseMessageSQLResult(result, derivedMessages, viewer);