diff --git a/experiment/src/org/labkey/experiment/api/ExperimentServiceImpl.java b/experiment/src/org/labkey/experiment/api/ExperimentServiceImpl.java
index 367d743da66..cd4d69cbd2e 100644
--- a/experiment/src/org/labkey/experiment/api/ExperimentServiceImpl.java
+++ b/experiment/src/org/labkey/experiment/api/ExperimentServiceImpl.java
@@ -1263,11 +1263,14 @@ public void indexDataClass(ExpDataClassImpl dataClass, SearchService.TaskIndexin
             if (table == null)
                 return;
 
-            // Index the data class if it has never been indexed OR it has changed since it was last indexed
+            indexDataClassData(dataClass, q);
+
+            // GitHub Issue 783: Server lockup when updating data class domain design
+            // Index DataClass after data indexing, to avoid holding locks on exp.DataClass table for too long
             SQLFragment sql = new SQLFragment("SELECT * FROM ")
                     .append(getTinfoDataClass(), "dc")
                     .append(" WHERE dc.LSID = ?").add(dataClass.getLSID())
-                    .append(" AND (dc.lastIndexed IS NULL OR dc.lastIndexed < ?)")
+                    .append(" AND (dc.lastIndexed IS NULL OR dc.lastIndexed < ?)") // Index the data class if it has never been indexed OR it has changed since it was last indexed
                     .add(dataClass.getModified());
 
             DataClass dClass = new SqlSelector(getExpSchema().getScope(), sql).getObject(DataClass.class);
@@ -1276,8 +1279,6 @@ public void indexDataClass(ExpDataClassImpl dataClass, SearchService.TaskIndexin
                 ExpDataClassImpl impl = new ExpDataClassImpl(dClass);
                 impl.index(q, table);
             }
-
-            indexDataClassData(dataClass, q);
         });
     }
 
@@ -8046,7 +8047,7 @@ public ValidationException updateDataClass(@NotNull Container c, @NotNull User u
             if (!errors.hasErrors())
             {
                 transaction.addCommitTask(() -> clearDataClassCache(c), DbScope.CommitTaskOption.IMMEDIATE, POSTCOMMIT, POSTROLLBACK);
-                transaction.addCommitTask(() -> indexDataClass(getDataClass(c, dataClass.getName()), SearchService.get().defaultTask().getQueue(c, SearchService.PRIORITY.modified)), POSTCOMMIT);
+                transaction.addCommitTask(() -> indexDataClass(dataClass, SearchService.get().defaultTask().getQueue(c, SearchService.PRIORITY.modified)), POSTCOMMIT);
                 transaction.commit();
             }
         }
diff --git a/experiment/src/org/labkey/experiment/api/SampleTypeServiceImpl.java b/experiment/src/org/labkey/experiment/api/SampleTypeServiceImpl.java
index af04d68fa32..94b1feb99a9 100644
--- a/experiment/src/org/labkey/experiment/api/SampleTypeServiceImpl.java
+++ b/experiment/src/org/labkey/experiment/api/SampleTypeServiceImpl.java
@@ -331,6 +331,10 @@ public void indexSampleType(ExpSampleType sampleType, SearchService.TaskIndexing
             return;
 
         queue.addRunnable((q) -> {
+            indexSampleTypeMaterials(sampleType, q);
+
+            // GitHub Issue 783: Server lockup when updating data class domain design
+            // Index MaterialSource after materials indexing, to avoid holding locks on exp.MaterialSource table for too long
             // Index all ExpMaterial that have never been indexed OR where either the ExpSampleType definition or ExpMaterial itself has changed since last indexed
             SQLFragment sql = new SQLFragment("SELECT * FROM ")
                     .append(getTinfoMaterialSource(), "ms")
@@ -345,8 +349,6 @@ public void indexSampleType(ExpSampleType sampleType, SearchService.TaskIndexing
                 ExpSampleTypeImpl impl = new ExpSampleTypeImpl(materialSource);
                 impl.index(q, null);
             }
-
-            indexSampleTypeMaterials(sampleType, q);
         });
     }