diff --git a/src/main/java/edu/stanford/protege/webprotege/postcoordinationservice/model/EntityCustomScalesValuesHistory.java b/src/main/java/edu/stanford/protege/webprotege/postcoordinationservice/model/EntityCustomScalesValuesHistory.java
index 56915a8..46ae113 100644
--- a/src/main/java/edu/stanford/protege/webprotege/postcoordinationservice/model/EntityCustomScalesValuesHistory.java
+++ b/src/main/java/edu/stanford/protege/webprotege/postcoordinationservice/model/EntityCustomScalesValuesHistory.java
@@ -2,6 +2,8 @@
 
 
 import com.fasterxml.jackson.annotation.*;
+import org.springframework.data.mongodb.core.index.CompoundIndex;
+import org.springframework.data.mongodb.core.index.CompoundIndexes;
 import org.springframework.data.mongodb.core.index.Indexed;
 import org.springframework.data.mongodb.core.mapping.*;
 
@@ -11,6 +13,9 @@
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 @Document(collection = POSTCOORDINATION_CUSTOM_SCALES_COLLECTION)
+@CompoundIndexes({
+        @CompoundIndex(name = "entity_iri_project_idx", def = "{'" + EntityCustomScalesValuesHistory.WHOFIC_ENTITY_IRI + "': 1, '" + EntityCustomScalesValuesHistory.PROJECT_ID + "': 1}")
+})
 public class EntityCustomScalesValuesHistory {
 
     public static final String POSTCOORDINATION_CUSTOM_SCALES_COLLECTION = "EntityPostCoordinationCustomScales";
@@ -23,6 +28,7 @@ public class EntityCustomScalesValuesHistory {
     private final String whoficEntityIri;
 
     @Field(PROJECT_ID)
+    @Indexed(name = "entityProjectId")
     private final String projectId;
 
     @Field(CUSTOM_SCALE_REVISIONS)
diff --git a/src/main/java/edu/stanford/protege/webprotege/postcoordinationservice/model/EntityPostCoordinationHistory.java b/src/main/java/edu/stanford/protege/webprotege/postcoordinationservice/model/EntityPostCoordinationHistory.java
index 50d9db0..9d58ba4 100644
--- a/src/main/java/edu/stanford/protege/webprotege/postcoordinationservice/model/EntityPostCoordinationHistory.java
+++ b/src/main/java/edu/stanford/protege/webprotege/postcoordinationservice/model/EntityPostCoordinationHistory.java
@@ -22,6 +22,7 @@ public class EntityPostCoordinationHistory {
     private final String whoficEntityIri;
 
     @Field(PROJECT_ID)
+    @Indexed(name = "entityIriProjectId")
     private final String projectId;
 
     @Field(SPEC_REVISIONS)