diff --git a/docs/manual/options.md b/docs/manual/options.md
index 451b8b5..0683eac 100644
--- a/docs/manual/options.md
+++ b/docs/manual/options.md
@@ -640,7 +640,7 @@ This setting limits the maximum number of bytes queued for retransmission. The d
 
 The unit must be specified explicitly. Recognised units: B (bytes), kB & KiB (2^10 bytes), MB & MiB (2^20 bytes), GB & GiB (2^30 bytes).
 
-The default value is: "50 kB".
+The default value is: "512 kB".
 
 
 #### //CycloneDDS/Domain/Internal/MaxQueuedRexmitMessages
diff --git a/etc/cyclonedds.rnc b/etc/cyclonedds.rnc
index 0d9aa14..1546c23 100644
--- a/etc/cyclonedds.rnc
+++ b/etc/cyclonedds.rnc
@@ -452,7 +452,7 @@ CycloneDDS configuration""" ] ]
         & [ a:documentation [ xml:lang="en" """
 <p>This setting limits the maximum number of bytes queued for retransmission. The default value of 0 is unlimited unless an AuxiliaryBandwidthLimit has been set, in which case it becomes NackDelay * AuxiliaryBandwidthLimit. It must be large enough to contain the largest sample that may need to be retransmitted.</p>
 <p>The unit must be specified explicitly. Recognised units: B (bytes), kB & KiB (2<sup>10</sup> bytes), MB & MiB (2<sup>20</sup> bytes), GB & GiB (2<sup>30</sup> bytes).</p>
-<p>The default value is: "50 kB".</p>""" ] ]
+<p>The default value is: "512 kB".</p>""" ] ]
         element MaxQueuedRexmitBytes {
           memsize
         }?
diff --git a/etc/cyclonedds.xsd b/etc/cyclonedds.xsd
index 749f867..cd2d0f4 100644
--- a/etc/cyclonedds.xsd
+++ b/etc/cyclonedds.xsd
@@ -739,7 +739,7 @@ CycloneDDS configuration</xs:documentation>
       <xs:documentation>
 &lt;p&gt;This setting limits the maximum number of bytes queued for retransmission. The default value of 0 is unlimited unless an AuxiliaryBandwidthLimit has been set, in which case it becomes NackDelay * AuxiliaryBandwidthLimit. It must be large enough to contain the largest sample that may need to be retransmitted.&lt;/p&gt;
 &lt;p&gt;The unit must be specified explicitly. Recognised units: B (bytes), kB &amp; KiB (2&lt;sup&gt;10&lt;/sup&gt; bytes), MB &amp; MiB (2&lt;sup&gt;20&lt;/sup&gt; bytes), GB &amp; GiB (2&lt;sup&gt;30&lt;/sup&gt; bytes).&lt;/p&gt;
-&lt;p&gt;The default value is: "50 kB".&lt;/p&gt;</xs:documentation>
+&lt;p&gt;The default value is: "512 kB".&lt;/p&gt;</xs:documentation>
     </xs:annotation>
   </xs:element>
   <xs:element name="MaxQueuedRexmitMessages" type="xs:integer">
diff --git a/src/core/ddsi/include/dds/ddsi/ddsi_cfgelems.h b/src/core/ddsi/include/dds/ddsi/ddsi_cfgelems.h
index 5a93760..2122812 100644
--- a/src/core/ddsi/include/dds/ddsi/ddsi_cfgelems.h
+++ b/src/core/ddsi/include/dds/ddsi/ddsi_cfgelems.h
@@ -1140,7 +1140,7 @@ static struct cfgelem internal_cfgelems[] = {
       "<p>This element allows configuring the base interval for sending "
       "writer heartbeats and the bounds within which it can vary.</p>"),
     UNIT("duration_inf")),
-  STRING("MaxQueuedRexmitBytes", NULL, 1, "50 kB",
+  STRING("MaxQueuedRexmitBytes", NULL, 1, "512 kB",
     MEMBER(max_queued_rexmit_bytes),
     FUNCTIONS(0, uf_memsize, 0, pf_memsize),
     DESCRIPTION(
diff --git a/src/core/ddsi/src/q_xmsg.c b/src/core/ddsi/src/q_xmsg.c
index 043b32b..ae172c7 100644
--- a/src/core/ddsi/src/q_xmsg.c
+++ b/src/core/ddsi/src/q_xmsg.c
@@ -492,7 +492,7 @@ int nn_xmsg_compare_fragid (const struct nn_xmsg *a, const struct nn_xmsg *b)
 
 size_t nn_xmsg_size (const struct nn_xmsg *m)
 {
-  return m->sz;
+  return m->sz + (m->refd_payload ? (size_t) m->refd_payload_iov.iov_len : 0);
 }
 
 enum nn_xmsg_kind nn_xmsg_kind (const struct nn_xmsg *m)