diff --git a/packages/amplify-graphql-index-transformer/src/__tests__/__snapshots__/amplify-graphql-index-transformer.test.ts.snap b/packages/amplify-graphql-index-transformer/src/__tests__/__snapshots__/amplify-graphql-index-transformer.test.ts.snap
index d820407008..75cccbcfca 100644
--- a/packages/amplify-graphql-index-transformer/src/__tests__/__snapshots__/amplify-graphql-index-transformer.test.ts.snap
+++ b/packages/amplify-graphql-index-transformer/src/__tests__/__snapshots__/amplify-graphql-index-transformer.test.ts.snap
@@ -2137,7 +2137,9 @@ $util.qr($mergedValues.put(\\"__typename\\", \\"Test\\"))
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"PutItem\\",
   \\"attributeValues\\":   $util.dynamodb.toMapValues($mergedValues),
-  \\"condition\\": $condition
+  \\"condition\\": $condition,
+  \\"customPartitionKey\\": \\"email\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $args.condition )
   $util.qr($ctx.stash.conditions.add($args.condition))
@@ -2220,7 +2222,9 @@ $util.qr($ctx.stash.metadata.put(\\"modelObjectKey\\", {
 #set( $args = $util.defaultIfNull($ctx.stash.transformedArgs, $ctx.args) )
 #set( $DeleteRequest = {
   \\"version\\": \\"2018-05-29\\",
-  \\"operation\\": \\"DeleteItem\\"
+  \\"operation\\": \\"DeleteItem\\",
+  \\"customPartitionKey\\": \\"email\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $ctx.stash.metadata.modelObjectKey )
   #set( $Key = $ctx.stash.metadata.modelObjectKey )
@@ -2429,7 +2433,9 @@ $util.qr($update.put(\\"expression\\", \\"$expression\\"))
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"UpdateItem\\",
   \\"key\\": $Key,
-  \\"update\\": $update
+  \\"update\\": $update,
+  \\"customPartitionKey\\": \\"email\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $Conditions )
   #if( $keyConditionExprNames )
@@ -2849,7 +2855,9 @@ $util.qr($mergedValues.put(\\"__typename\\", \\"Item\\"))
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"PutItem\\",
   \\"attributeValues\\":   $util.dynamodb.toMapValues($mergedValues),
-  \\"condition\\": $condition
+  \\"condition\\": $condition,
+  \\"customPartitionKey\\": \\"orderId\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $args.condition )
   $util.qr($ctx.stash.conditions.add($args.condition))
@@ -2932,7 +2940,9 @@ $util.qr($ctx.stash.metadata.put(\\"modelObjectKey\\", {
 #set( $args = $util.defaultIfNull($ctx.stash.transformedArgs, $ctx.args) )
 #set( $DeleteRequest = {
   \\"version\\": \\"2018-05-29\\",
-  \\"operation\\": \\"DeleteItem\\"
+  \\"operation\\": \\"DeleteItem\\",
+  \\"customPartitionKey\\": \\"orderId\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $ctx.stash.metadata.modelObjectKey )
   #set( $Key = $ctx.stash.metadata.modelObjectKey )
@@ -3148,6 +3158,8 @@ $util.qr($update.put(\\"expression\\", \\"$expression\\"))
   \\"operation\\": \\"UpdateItem\\",
   \\"key\\": $Key,
   \\"update\\": $update,
+  \\"customPartitionKey\\": \\"orderId\\",
+  \\"populateIndexFields\\":   true,
   \\"_version\\": $util.defaultIfNull($args.input[\\"_version\\"], 0)
 } )
 #if( $Conditions )
@@ -3911,14 +3923,12 @@ null
 {
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"Sync\\",
-  \\"filter\\":   #if( $filter )
-$util.toJson($filter)
-  #else
-null
-  #end,
+  \\"filter\\": #if( $filter ) $util.toJson($filter) #else null #end,
   \\"limit\\": $util.defaultIfNull($args.limit, 100),
   \\"lastSync\\": $util.toJson($util.defaultIfNull($args.lastSync, null)),
-  \\"nextToken\\": $util.toJson($util.defaultIfNull($args.nextToken, null))
+  \\"nextToken\\": $util.toJson($util.defaultIfNull($args.nextToken, null)),
+  \\"basePartitionKey\\": #if( $filter && $$filter.orderId ) $filter.orderId.eq #else null #end,
+  \\"deltaIndexName\\": \\"deltaSyncGSI\\"
 }
 ## [End] Sync Request template. **",
   "Query.syncItems.res.vtl": "## [Start] ResponseTemplate. **
@@ -4660,11 +4670,7 @@ null
 {
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"Sync\\",
-  \\"filter\\":   #if( $filter )
-$util.toJson($filter)
-  #else
-null
-  #end,
+  \\"filter\\": #if( $filter ) $util.toJson($filter) #else null #end,
   \\"limit\\": $util.defaultIfNull($args.limit, 100),
   \\"lastSync\\": $util.toJson($util.defaultIfNull($args.lastSync, null)),
   \\"nextToken\\": $util.toJson($util.defaultIfNull($args.nextToken, null))
@@ -5409,11 +5415,7 @@ null
 {
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"Sync\\",
-  \\"filter\\":   #if( $filter )
-$util.toJson($filter)
-  #else
-null
-  #end,
+  \\"filter\\": #if( $filter ) $util.toJson($filter) #else null #end,
   \\"limit\\": $util.defaultIfNull($args.limit, 100),
   \\"lastSync\\": $util.toJson($util.defaultIfNull($args.lastSync, null)),
   \\"nextToken\\": $util.toJson($util.defaultIfNull($args.nextToken, null))
@@ -5539,7 +5541,9 @@ $util.qr($mergedValues.put(\\"__typename\\", \\"Item\\"))
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"PutItem\\",
   \\"attributeValues\\":   $util.dynamodb.toMapValues($mergedValues),
-  \\"condition\\": $condition
+  \\"condition\\": $condition,
+  \\"customPartitionKey\\": \\"orderId\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $args.condition )
   $util.qr($ctx.stash.conditions.add($args.condition))
@@ -5622,7 +5626,9 @@ $util.qr($ctx.stash.metadata.put(\\"modelObjectKey\\", {
 #set( $args = $util.defaultIfNull($ctx.stash.transformedArgs, $ctx.args) )
 #set( $DeleteRequest = {
   \\"version\\": \\"2018-05-29\\",
-  \\"operation\\": \\"DeleteItem\\"
+  \\"operation\\": \\"DeleteItem\\",
+  \\"customPartitionKey\\": \\"orderId\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $ctx.stash.metadata.modelObjectKey )
   #set( $Key = $ctx.stash.metadata.modelObjectKey )
@@ -5836,7 +5842,9 @@ $util.qr($update.put(\\"expression\\", \\"$expression\\"))
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"UpdateItem\\",
   \\"key\\": $Key,
-  \\"update\\": $update
+  \\"update\\": $update,
+  \\"customPartitionKey\\": \\"orderId\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $Conditions )
   #if( $keyConditionExprNames )
diff --git a/packages/amplify-graphql-index-transformer/src/__tests__/__snapshots__/amplify-graphql-primary-key-transformer.test.ts.snap b/packages/amplify-graphql-index-transformer/src/__tests__/__snapshots__/amplify-graphql-primary-key-transformer.test.ts.snap
index 6a2998cf14..0da358eb72 100644
--- a/packages/amplify-graphql-index-transformer/src/__tests__/__snapshots__/amplify-graphql-primary-key-transformer.test.ts.snap
+++ b/packages/amplify-graphql-index-transformer/src/__tests__/__snapshots__/amplify-graphql-primary-key-transformer.test.ts.snap
@@ -48,7 +48,9 @@ $util.qr($mergedValues.put(\\"__typename\\", \\"Test\\"))
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"PutItem\\",
   \\"attributeValues\\":   $util.dynamodb.toMapValues($mergedValues),
-  \\"condition\\": $condition
+  \\"condition\\": $condition,
+  \\"customPartitionKey\\": \\"email\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $args.condition )
   $util.qr($ctx.stash.conditions.add($args.condition))
@@ -131,7 +133,9 @@ $util.qr($ctx.stash.metadata.put(\\"modelObjectKey\\", {
 #set( $args = $util.defaultIfNull($ctx.stash.transformedArgs, $ctx.args) )
 #set( $DeleteRequest = {
   \\"version\\": \\"2018-05-29\\",
-  \\"operation\\": \\"DeleteItem\\"
+  \\"operation\\": \\"DeleteItem\\",
+  \\"customPartitionKey\\": \\"email\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $ctx.stash.metadata.modelObjectKey )
   #set( $Key = $ctx.stash.metadata.modelObjectKey )
@@ -345,7 +349,9 @@ $util.qr($update.put(\\"expression\\", \\"$expression\\"))
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"UpdateItem\\",
   \\"key\\": $Key,
-  \\"update\\": $update
+  \\"update\\": $update,
+  \\"customPartitionKey\\": \\"email\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $Conditions )
   #if( $keyConditionExprNames )
@@ -694,7 +700,9 @@ $util.qr($mergedValues.put(\\"__typename\\", \\"Test\\"))
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"PutItem\\",
   \\"attributeValues\\":   $util.dynamodb.toMapValues($mergedValues),
-  \\"condition\\": $condition
+  \\"condition\\": $condition,
+  \\"customPartitionKey\\": \\"email\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $args.condition )
   $util.qr($ctx.stash.conditions.add($args.condition))
@@ -777,7 +785,9 @@ $util.qr($ctx.stash.metadata.put(\\"modelObjectKey\\", {
 #set( $args = $util.defaultIfNull($ctx.stash.transformedArgs, $ctx.args) )
 #set( $DeleteRequest = {
   \\"version\\": \\"2018-05-29\\",
-  \\"operation\\": \\"DeleteItem\\"
+  \\"operation\\": \\"DeleteItem\\",
+  \\"customPartitionKey\\": \\"email\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $ctx.stash.metadata.modelObjectKey )
   #set( $Key = $ctx.stash.metadata.modelObjectKey )
@@ -986,7 +996,9 @@ $util.qr($update.put(\\"expression\\", \\"$expression\\"))
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"UpdateItem\\",
   \\"key\\": $Key,
-  \\"update\\": $update
+  \\"update\\": $update,
+  \\"customPartitionKey\\": \\"email\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $Conditions )
   #if( $keyConditionExprNames )
@@ -1837,7 +1849,9 @@ $util.qr($mergedValues.put(\\"__typename\\", \\"Test\\"))
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"PutItem\\",
   \\"attributeValues\\":   $util.dynamodb.toMapValues($mergedValues),
-  \\"condition\\": $condition
+  \\"condition\\": $condition,
+  \\"customPartitionKey\\": \\"status\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $args.condition )
   $util.qr($ctx.stash.conditions.add($args.condition))
@@ -1920,7 +1934,9 @@ $util.qr($ctx.stash.metadata.put(\\"modelObjectKey\\", {
 #set( $args = $util.defaultIfNull($ctx.stash.transformedArgs, $ctx.args) )
 #set( $DeleteRequest = {
   \\"version\\": \\"2018-05-29\\",
-  \\"operation\\": \\"DeleteItem\\"
+  \\"operation\\": \\"DeleteItem\\",
+  \\"customPartitionKey\\": \\"status\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $ctx.stash.metadata.modelObjectKey )
   #set( $Key = $ctx.stash.metadata.modelObjectKey )
@@ -2129,7 +2145,9 @@ $util.qr($update.put(\\"expression\\", \\"$expression\\"))
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"UpdateItem\\",
   \\"key\\": $Key,
-  \\"update\\": $update
+  \\"update\\": $update,
+  \\"customPartitionKey\\": \\"status\\",
+  \\"populateIndexFields\\":   true
 } )
 #if( $Conditions )
   #if( $keyConditionExprNames )
diff --git a/packages/amplify-graphql-model-transformer/src/__tests__/__snapshots__/model-transformer.test.ts.snap b/packages/amplify-graphql-model-transformer/src/__tests__/__snapshots__/model-transformer.test.ts.snap
index 831bb57eac..e3a3677ca6 100644
--- a/packages/amplify-graphql-model-transformer/src/__tests__/__snapshots__/model-transformer.test.ts.snap
+++ b/packages/amplify-graphql-model-transformer/src/__tests__/__snapshots__/model-transformer.test.ts.snap
@@ -1216,11 +1216,7 @@ $util.toJson({})
 {
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"Sync\\",
-  \\"filter\\":   #if( $filter )
-$util.toJson($filter)
-  #else
-null
-  #end,
+  \\"filter\\": #if( $filter ) $util.toJson($filter) #else null #end,
   \\"limit\\": $util.defaultIfNull($args.limit, 100),
   \\"lastSync\\": $util.toJson($util.defaultIfNull($args.lastSync, null)),
   \\"nextToken\\": $util.toJson($util.defaultIfNull($args.nextToken, null))
@@ -1758,11 +1754,7 @@ $util.toJson({})
 {
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"Sync\\",
-  \\"filter\\":   #if( $filter )
-$util.toJson($filter)
-  #else
-null
-  #end,
+  \\"filter\\": #if( $filter ) $util.toJson($filter) #else null #end,
   \\"limit\\": $util.defaultIfNull($args.limit, 100),
   \\"lastSync\\": $util.toJson($util.defaultIfNull($args.lastSync, null)),
   \\"nextToken\\": $util.toJson($util.defaultIfNull($args.nextToken, null))
@@ -2300,11 +2292,7 @@ $util.toJson({})
 {
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"Sync\\",
-  \\"filter\\":   #if( $filter )
-$util.toJson($filter)
-  #else
-null
-  #end,
+  \\"filter\\": #if( $filter ) $util.toJson($filter) #else null #end,
   \\"limit\\": $util.defaultIfNull($args.limit, 100),
   \\"lastSync\\": $util.toJson($util.defaultIfNull($args.lastSync, null)),
   \\"nextToken\\": $util.toJson($util.defaultIfNull($args.nextToken, null))
@@ -4342,11 +4330,7 @@ exports[`ModelTransformer:  the datastore table should be configured 1`] = `
 {
   \\"version\\": \\"2018-05-29\\",
   \\"operation\\": \\"Sync\\",
-  \\"filter\\":   #if( $filter )
-$util.toJson($filter)
-  #else
-null
-  #end,
+  \\"filter\\": #if( $filter ) $util.toJson($filter) #else null #end,
   \\"limit\\": $util.defaultIfNull($args.limit, 100),
   \\"lastSync\\": $util.toJson($util.defaultIfNull($args.lastSync, null)),
   \\"nextToken\\": $util.toJson($util.defaultIfNull($args.nextToken, null))
diff --git a/packages/amplify-graphql-model-transformer/src/__tests__/model-transformer.test.ts b/packages/amplify-graphql-model-transformer/src/__tests__/model-transformer.test.ts
index 2dd58371e0..2dcf54b241 100644
--- a/packages/amplify-graphql-model-transformer/src/__tests__/model-transformer.test.ts
+++ b/packages/amplify-graphql-model-transformer/src/__tests__/model-transformer.test.ts
@@ -1143,8 +1143,34 @@ describe('ModelTransformer: ', () => {
             AttributeName: 'ds_sk',
             AttributeType: 'S',
           },
+          {
+            AttributeName: 'gsi_ds_pk',
+            AttributeType: 'S',
+          },
+          {
+            AttributeName: 'gsi_ds_sk',
+            AttributeType: 'S',
+          }
         ],
         BillingMode: 'PAY_PER_REQUEST',
+        GlobalSecondaryIndexes: [
+          {
+            IndexName: "deltaSyncGSI",
+            KeySchema: [
+              {
+                AttributeName: "gsi_ds_pk",
+                KeyType: "HASH"
+              },
+              {
+                AttributeName: "gsi_ds_sk",
+                KeyType: "RANGE"
+              }
+            ],
+            Projection: {
+              ProjectionType: "ALL"
+            }
+          }
+        ],
         StreamSpecification: {
           StreamViewType: 'NEW_AND_OLD_IMAGES',
         },
diff --git a/packages/amplify-graphql-model-transformer/src/graphql-model-transformer.ts b/packages/amplify-graphql-model-transformer/src/graphql-model-transformer.ts
index 63099626bc..6eb7c34d4d 100644
--- a/packages/amplify-graphql-model-transformer/src/graphql-model-transformer.ts
+++ b/packages/amplify-graphql-model-transformer/src/graphql-model-transformer.ts
@@ -45,6 +45,7 @@ import {
   FieldDefinitionNode,
   InputObjectTypeDefinitionNode,
   InputValueDefinitionNode,
+  ListValueNode,
   ObjectTypeDefinitionNode,
 } from 'graphql';
 import {
@@ -143,6 +144,8 @@ type ModelTransformerOptions = {
   SyncConfig?: SyncConfig;
 };
 
+const DEFAULT_ID_FIELD_NAME = 'id';
+
 /**
  * ModelTransformer
  */
@@ -504,13 +507,15 @@ export class ModelTransformer extends TransformerModelBase implements Transforme
     const dataSource = this.datasourceMap[type.name.value];
     const resolverKey = `Update${generateResolverKey(typeName, fieldName)}`;
     if (!this.resolverMap[resolverKey]) {
+      const hasCustomPrimaryKey = this.hasCustomPrimaryKey(type);
+      const partitionKey = this.getPartitionKey(type);
       const resolver = ctx.resolvers.generateMutationResolver(
         typeName,
         fieldName,
         resolverLogicalId,
         dataSource,
         MappingTemplate.s3MappingTemplateFromString(
-          generateUpdateRequestTemplate(typeName, isSyncEnabled),
+          generateUpdateRequestTemplate(typeName, isSyncEnabled, hasCustomPrimaryKey, partitionKey),
           `${typeName}.${fieldName}.req.vtl`,
         ),
         MappingTemplate.s3MappingTemplateFromString(
@@ -541,13 +546,15 @@ export class ModelTransformer extends TransformerModelBase implements Transforme
     const isSyncEnabled = ctx.isProjectUsingDataStore();
     const dataSource = this.datasourceMap[type.name.value];
     const resolverKey = `delete${generateResolverKey(typeName, fieldName)}`;
+    const hasCustomPrimaryKey = this.hasCustomPrimaryKey(type);
+    const partitionKey = this.getPartitionKey(type);
     if (!this.resolverMap[resolverKey]) {
       this.resolverMap[resolverKey] = ctx.resolvers.generateMutationResolver(
         typeName,
         fieldName,
         resolverLogicalId,
         dataSource,
-        MappingTemplate.s3MappingTemplateFromString(generateDeleteRequestTemplate(isSyncEnabled), `${typeName}.${fieldName}.req.vtl`),
+        MappingTemplate.s3MappingTemplateFromString(generateDeleteRequestTemplate(isSyncEnabled, hasCustomPrimaryKey, partitionKey), `${typeName}.${fieldName}.req.vtl`),
         MappingTemplate.s3MappingTemplateFromString(
           generateDefaultResponseMappingTemplate(isSyncEnabled, true),
           `${typeName}.${fieldName}.res.vtl`,
@@ -625,12 +632,14 @@ export class ModelTransformer extends TransformerModelBase implements Transforme
     const dataSource = this.datasourceMap[type.name.value];
     const resolverKey = `Sync${generateResolverKey(typeName, fieldName)}`;
     if (!this.resolverMap[resolverKey]) {
+      const hasCustomPrimaryKey = this.hasCustomPrimaryKey(type);
+      const partitionKeyName = this.getPartitionKeyName(type);
       this.resolverMap[resolverKey] = ctx.resolvers.generateQueryResolver(
         typeName,
         fieldName,
         resolverLogicalId,
         dataSource,
-        MappingTemplate.s3MappingTemplateFromString(generateSyncRequestTemplate(), `${typeName}.${fieldName}.req.vtl`),
+        MappingTemplate.s3MappingTemplateFromString(generateSyncRequestTemplate(hasCustomPrimaryKey, partitionKeyName), `${typeName}.${fieldName}.req.vtl`),
         MappingTemplate.s3MappingTemplateFromString(
           generateDefaultResponseMappingTemplate(isSyncEnabled),
           `${typeName}.${fieldName}.res.vtl`,
@@ -879,12 +888,14 @@ export class ModelTransformer extends TransformerModelBase implements Transforme
     const resolverKey = `Create${generateResolverKey(typeName, fieldName)}`;
     const modelIndexFields = type.fields!.filter(field => field.directives?.some(it => it.name.value === 'index')).map(it => it.name.value);
     if (!this.resolverMap[resolverKey]) {
+      const hasCustomPrimaryKey = this.hasCustomPrimaryKey(type);
+      const partitionKey = this.getPartitionKey(type);
       const resolver = ctx.resolvers.generateMutationResolver(
         typeName,
         fieldName,
         resolverLogicalId,
         dataSource,
-        MappingTemplate.s3MappingTemplateFromString(generateCreateRequestTemplate(type.name.value, modelIndexFields), `${typeName}.${fieldName}.req.vtl`),
+        MappingTemplate.s3MappingTemplateFromString(generateCreateRequestTemplate(type.name.value, modelIndexFields, hasCustomPrimaryKey, partitionKey), `${typeName}.${fieldName}.req.vtl`),
         MappingTemplate.s3MappingTemplateFromString(
           generateDefaultResponseMappingTemplate(isSyncEnabled, true),
           `${typeName}.${fieldName}.res.vtl`,
@@ -1391,4 +1402,56 @@ export class ModelTransformer extends TransformerModelBase implements Transforme
     EnableDeletionProtection: false,
     ...options,
   });
+
+  /**
+   * Returns true if the model contains a custom primary key.
+   * Custom Primary Key is a renamed partition key with at least one sort key.
+   * @param obj ObjectTypeDefinitionNode
+   * @returns a boolean
+   */
+  private hasCustomPrimaryKey = (obj: ObjectTypeDefinitionNode): boolean => {
+    const primaryKeyField = obj.fields?.find(field => field.directives?.find(directive => directive.name.value === 'primaryKey'));
+    if (!primaryKeyField || primaryKeyField.name.value === DEFAULT_ID_FIELD_NAME) {
+      return false;
+    }
+
+    // eslint-disable-next-line @typescript-eslint/no-non-null-asserted-optional-chain
+    const primaryKeyDirective = primaryKeyField.directives?.find(directive => directive.name.value === 'primaryKey')!;
+    const sortKeysArgument = primaryKeyDirective.arguments?.find(arg => arg.name.value === 'sortKeyFields');
+    if (sortKeysArgument && sortKeysArgument.value?.kind == 'StringValue') {
+      return true;
+    }
+    if (!sortKeysArgument || (sortKeysArgument.value as ListValueNode)?.values?.length === 0) {
+      return false;
+    }
+
+    return true;
+  }
+
+  /**
+   * Returns partition key of the type
+   * Custom Primary Key is a renamed partition key with at least one sort key.
+   * @param obj ObjectTypeDefinitionNode
+   * @returns a string
+   */
+   private getPartitionKey = (obj: ObjectTypeDefinitionNode): string => {
+    const primaryKeyField = obj.fields?.find(field => field.directives?.find(directive => directive.name.value === 'primaryKey'));
+    if (!primaryKeyField || primaryKeyField.name.value === DEFAULT_ID_FIELD_NAME) {
+      return DEFAULT_ID_FIELD_NAME;
+    }
+    return primaryKeyField.name.value;
+  }
+
+  /**
+   * Returns the field name of the partition key.
+   * @param obj ObjectTypeDefinitionNode
+   * @returns a string
+   */
+   private getPartitionKeyName = (obj: ObjectTypeDefinitionNode): string => {
+     const primaryKeyField = obj.fields?.find(field => field.directives?.find(directive => directive.name.value === 'primaryKey'));
+     if (!primaryKeyField) {
+       return DEFAULT_ID_FIELD_NAME;
+     }
+     return primaryKeyField.name.value;
+   }
 }
diff --git a/packages/amplify-graphql-model-transformer/src/resolvers/mutation.ts b/packages/amplify-graphql-model-transformer/src/resolvers/mutation.ts
index beed0fcedc..a3a74d07b8 100644
--- a/packages/amplify-graphql-model-transformer/src/resolvers/mutation.ts
+++ b/packages/amplify-graphql-model-transformer/src/resolvers/mutation.ts
@@ -26,7 +26,7 @@ import { generateConditionSlot } from './common';
  * Generates VTL template in update mutation
  * @param modelName Name of the model
  */
-export const generateUpdateRequestTemplate = (modelName: string, isSyncEnabled: boolean): string => {
+export const generateUpdateRequestTemplate = (modelName: string, isSyncEnabled: boolean, hasCustomPrimaryKey: boolean, partitionKey: string): string => {
   const objectKeyVariable = 'ctx.stash.metadata.modelObjectKey';
   const keyFields: StringNode[] = [str('id')];
   if (isSyncEnabled) {
@@ -133,6 +133,10 @@ export const generateUpdateRequestTemplate = (modelName: string, isSyncEnabled:
         operation: str('UpdateItem'),
         key: ref('Key'),
         update: ref('update'),
+        ...(hasCustomPrimaryKey && {
+          customPartitionKey: str(`${partitionKey}`),
+          populateIndexFields: raw(`${hasCustomPrimaryKey}`),
+        }), 
         ...(isSyncEnabled && { _version: ref('util.defaultIfNull($args.input["_version"], 0)') }),
       }),
     ),
@@ -152,7 +156,7 @@ export const generateUpdateRequestTemplate = (modelName: string, isSyncEnabled:
  * Generates VTL template in create mutation
  * @param modelName Name of the model
  */
-export const generateCreateRequestTemplate = (modelName: string, modelIndexFields: string[]): string => {
+export const generateCreateRequestTemplate = (modelName: string, modelIndexFields: string[], hasCustomPrimaryKey: boolean, partitionKey: string): string => {
   const statements: Expression[] = [
     setArgs,
     // Generate conditions
@@ -182,6 +186,10 @@ export const generateCreateRequestTemplate = (modelName: string, modelIndexField
         operation: str('PutItem'),
         attributeValues: methodCall(ref('util.dynamodb.toMapValues'), ref('mergedValues')),
         condition: ref('condition'),
+        ...(hasCustomPrimaryKey && {
+          customPartitionKey: str(`${partitionKey}`),
+          populateIndexFields: raw(`${hasCustomPrimaryKey}`),
+        }),
       }),
     ),
 
@@ -256,7 +264,7 @@ export const generateCreateInitSlotTemplate = (modelConfig: ModelDirectiveConfig
  * Generates VTL template in delete mutation
  *
  */
-export const generateDeleteRequestTemplate = (isSyncEnabled: boolean): string => {
+export const generateDeleteRequestTemplate = (isSyncEnabled: boolean, hasCustomPrimaryKey: boolean, partitionKey: string): string => {
   const statements: Expression[] = [
     setArgs,
     set(
@@ -264,6 +272,10 @@ export const generateDeleteRequestTemplate = (isSyncEnabled: boolean): string =>
       obj({
         version: str('2018-05-29'),
         operation: str('DeleteItem'),
+        ...(hasCustomPrimaryKey && {
+          customPartitionKey: str(`${partitionKey}`),
+          populateIndexFields: raw(`${hasCustomPrimaryKey}`),
+        }),
       }),
     ),
     ifElse(
diff --git a/packages/amplify-graphql-model-transformer/src/resolvers/query.ts b/packages/amplify-graphql-model-transformer/src/resolvers/query.ts
index 28276af07a..cb6f02bc8d 100644
--- a/packages/amplify-graphql-model-transformer/src/resolvers/query.ts
+++ b/packages/amplify-graphql-model-transformer/src/resolvers/query.ts
@@ -20,12 +20,14 @@ import {
   list,
   forEach,
   nul,
+  raw,
 } from 'graphql-mapping-template';
-import { ResourceConstants, setArgs } from 'graphql-transformer-common';
+import { ResourceConstants, setArgs, SyncResourceIDs } from 'graphql-transformer-common';
+
 const authFilter = ref('ctx.stash.authFilter');
 
 /**
- * Generate get query resolver template
+ * Generate get query resolver request template
  */
 export const generateGetRequestTemplate = (): string => {
   const statements: Expression[] = [
@@ -74,6 +76,9 @@ export const generateGetRequestTemplate = (): string => {
   return printBlock('Get Request template')(compoundExpression(statements));
 };
 
+/**
+ * Generates the Get query response template
+ */
 export const generateGetResponseTemplate = (isSyncEnabled: boolean): string => {
   const statements = new Array<Expression>();
   if (isSyncEnabled) {
@@ -96,13 +101,16 @@ export const generateGetResponseTemplate = (isSyncEnabled: boolean): string => {
   return printBlock('Get Response template')(compoundExpression(statements));
 };
 
+/**
+ * Generates the List query request template
+ */
 export const generateListRequestTemplate = (): string => {
   const requestVariable = 'ListRequest';
   const modelQueryObj = 'ctx.stash.modelQueryExpression';
   const indexNameVariable = 'ctx.stash.metadata.index';
   const expression = compoundExpression([
     setArgs,
-    set(ref('limit'), methodCall(ref(`util.defaultIfNull`), ref('args.limit'), int(100))),
+    set(ref('limit'), methodCall(ref('util.defaultIfNull'), ref('args.limit'), int(100))),
     set(
       ref(requestVariable),
       obj({
@@ -123,7 +131,7 @@ export const generateListRequestTemplate = (): string => {
       not(isNullOrEmpty(ref('filter'))),
       compoundExpression([
         set(
-          ref(`filterExpression`),
+          ref('filterExpression'),
           methodCall(ref('util.parseJson'), methodCall(ref('util.transform.toDynamoDBFilterExpression'), ref('filter'))),
         ),
         iff(
@@ -137,7 +145,7 @@ export const generateListRequestTemplate = (): string => {
               equals(methodCall(ref('filterExpression.expressionValues.size')), int(0)),
               qref(methodCall(ref('filterExpression.remove'), str('expressionValues'))),
             ),
-            set(ref(`${requestVariable}.filter`), ref(`filterExpression`)),
+            set(ref(`${requestVariable}.filter`), ref('filterExpression')),
           ]),
         ),
       ]),
@@ -164,45 +172,58 @@ export const generateListRequestTemplate = (): string => {
   return printBlock('List Request')(expression);
 };
 
-export const generateSyncRequestTemplate = (): string => {
-  return printBlock('Sync Request template')(
-    compoundExpression([
-      setArgs,
-      ifElse(
-        not(isNullOrEmpty(authFilter)),
-        compoundExpression([
-          set(ref('filter'), authFilter),
-          iff(not(isNullOrEmpty(ref('args.filter'))), set(ref('filter'), obj({ and: list([ref('filter'), ref('args.filter')]) }))),
-        ]),
-        iff(not(isNullOrEmpty(ref('args.filter'))), set(ref('filter'), ref('args.filter'))),
-      ),
-      iff(
-        not(isNullOrEmpty(ref('filter'))),
-        compoundExpression([
-          set(
-            ref(`filterExpression`),
-            methodCall(ref('util.parseJson'), methodCall(ref('util.transform.toDynamoDBFilterExpression'), ref('filter'))),
-          ),
-          iff(
-            not(methodCall(ref('util.isNullOrBlank'), ref('filterExpression.expression'))),
-            compoundExpression([
-              iff(
-                equals(methodCall(ref('filterExpression.expressionValues.size')), int(0)),
-                qref(methodCall(ref('filterExpression.remove'), str('expressionValues'))),
-              ),
-              set(ref('filter'), ref('filterExpression')),
-            ]),
-          ),
-        ]),
-      ),
-      obj({
-        version: str('2018-05-29'),
-        operation: str('Sync'),
-        filter: ifElse(ref('filter'), ref('util.toJson($filter)'), nul()),
-        limit: ref(`util.defaultIfNull($args.limit, ${ResourceConstants.DEFAULT_SYNC_QUERY_PAGE_LIMIT})`),
-        lastSync: ref('util.toJson($util.defaultIfNull($args.lastSync, null))'),
-        nextToken: ref('util.toJson($util.defaultIfNull($args.nextToken, null))'),
+/**
+ * Generates the Sync query request template
+ */
+export const generateSyncRequestTemplate = (hasCustomPrimaryKey: boolean, partitionKeyName: string): string => printBlock('Sync Request template')(
+  compoundExpression([
+    setArgs,
+    ifElse(
+      not(isNullOrEmpty(authFilter)),
+      compoundExpression([
+        set(ref('filter'), authFilter),
+        iff(not(isNullOrEmpty(ref('args.filter'))), set(ref('filter'), obj({ and: list([ref('filter'), ref('args.filter')]) }))),
+      ]),
+      iff(not(isNullOrEmpty(ref('args.filter'))), set(ref('filter'), ref('args.filter'))),
+    ),
+    iff(
+      not(isNullOrEmpty(ref('filter'))),
+      compoundExpression([
+        set(
+          ref('filterExpression'),
+          methodCall(ref('util.parseJson'), methodCall(ref('util.transform.toDynamoDBFilterExpression'), ref('filter'))),
+        ),
+        iff(
+          not(methodCall(ref('util.isNullOrBlank'), ref('filterExpression.expression'))),
+          compoundExpression([
+            iff(
+              equals(methodCall(ref('filterExpression.expressionValues.size')), int(0)),
+              qref(methodCall(ref('filterExpression.remove'), str('expressionValues'))),
+            ),
+            set(ref('filter'), ref('filterExpression')),
+          ]),
+        ),
+      ]),
+    ),
+    obj({
+      version: str('2018-05-29'),
+      operation: str('Sync'),
+      filter: ifElse(ref('filter'), ref('util.toJson($filter)'), nul(), true),
+      limit: ref(`util.defaultIfNull($args.limit, ${ResourceConstants.DEFAULT_SYNC_QUERY_PAGE_LIMIT})`),
+      lastSync: ref('util.toJson($util.defaultIfNull($args.lastSync, null))'),
+      nextToken: ref('util.toJson($util.defaultIfNull($args.nextToken, null))'),
+      ...(hasCustomPrimaryKey && {
+        basePartitionKey: ifElse(
+          and([
+            ref('filter'), 
+            ref(`$filter.${partitionKeyName}`),
+          ]),
+          raw(`$filter.${partitionKeyName}.eq`),
+          nul(),
+          true,
+        ),
+        deltaIndexName: str(SyncResourceIDs.syncGSIName),
       }),
-    ]),
-  );
-};
+    }),
+  ]),
+);
diff --git a/packages/amplify-graphql-transformer-core/src/transformation/sync-utils.ts b/packages/amplify-graphql-transformer-core/src/transformation/sync-utils.ts
index 26a61751f7..b929dd40ca 100644
--- a/packages/amplify-graphql-transformer-core/src/transformation/sync-utils.ts
+++ b/packages/amplify-graphql-transformer-core/src/transformation/sync-utils.ts
@@ -1,27 +1,34 @@
-import { AttributeType, BillingMode, StreamViewType, Table } from '@aws-cdk/aws-dynamodb';
+import {
+  AttributeType, BillingMode, StreamViewType, Table,
+} from '@aws-cdk/aws-dynamodb';
 import * as cdk from '@aws-cdk/core';
 import * as iam from '@aws-cdk/aws-iam';
 import { ResourceConstants, SyncResourceIDs } from 'graphql-transformer-common';
-import { TransformerContext } from '../transformer-context';
-import { ResolverConfig, SyncConfig, SyncConfigLambda } from '../config/transformer-config';
 import {
   StackManagerProvider,
   TransformerContextProvider,
   TransformerSchemaVisitStepContextProvider,
   TransformerTransformSchemaStepContextProvider,
 } from '@aws-amplify/graphql-transformer-interfaces';
+// eslint-disable-next-line import/no-cycle
+import { TransformerContext } from '../transformer-context';
+import { ResolverConfig, SyncConfig, SyncConfigLambda } from '../config/transformer-config';
 
 type DeltaSyncConfig = {
-  DeltaSyncTableName: any;
+  DeltaSyncTableName: unknown;
   DeltaSyncTableTTL: number;
   BaseTableTTL: number;
 };
 
-export function createSyncTable(context: TransformerContext) {
+/**
+ * Creates the SyncTable required for the data store
+ * @param context TransformerContext
+ */
+export const createSyncTable = (context: TransformerContext): void => {
   const stack = context.stackManager.getStackFor(SyncResourceIDs.syncTableName);
   const tableName = context.resourceHelper.generateTableName(SyncResourceIDs.syncTableName);
   // eslint-disable-next-line no-new
-  new Table(stack, SyncResourceIDs.syncDataSourceID, {
+  const table = new Table(stack, SyncResourceIDs.syncDataSourceID, {
     tableName,
     partitionKey: {
       name: SyncResourceIDs.syncPrimaryKey,
@@ -37,10 +44,25 @@ export function createSyncTable(context: TransformerContext) {
     timeToLiveAttribute: '_ttl',
   });
 
+  // Add the GSI for delta sync table required for the data store.
+  // This index is used for Custom Primary Key scenarios only.
+  // AppSync will not populate these fields if the model doesn't contain a custom primary key
+  table.addGlobalSecondaryIndex({
+    indexName: SyncResourceIDs.syncGSIName,
+    partitionKey: {
+      name: SyncResourceIDs.syncGSIPartitionKey,
+      type: AttributeType.STRING,
+    },
+    sortKey: {
+      name: SyncResourceIDs.syncGSISortKey,
+      type: AttributeType.STRING,
+    },
+  });
+
   createSyncIAMRole(context, stack, tableName);
-}
+};
 
-function createSyncIAMRole(context: TransformerContext, stack: cdk.Stack, tableName: string) {
+const createSyncIAMRole = (context: TransformerContext, stack: cdk.Stack, tableName: string): void => {
   const role = new iam.Role(stack, SyncResourceIDs.syncIAMRoleName, {
     roleName: context.resourceHelper.generateIAMRoleName(SyncResourceIDs.syncIAMRoleName),
     assumedBy: new iam.ServicePrincipal('appsync.amazonaws.com'),
@@ -75,28 +97,35 @@ function createSyncIAMRole(context: TransformerContext, stack: cdk.Stack, tableN
       ],
     }),
   );
-}
-
-export function syncDataSourceConfig(): DeltaSyncConfig {
-  return {
-    DeltaSyncTableName: joinWithEnv('-', [
-      SyncResourceIDs.syncTableName,
-      cdk.Fn.getAtt(ResourceConstants.RESOURCES.GraphQLAPILogicalID, 'ApiId'),
-    ]),
-    DeltaSyncTableTTL: 30,
-    BaseTableTTL: 43200, // 30 days
-  };
-}
+};
 
-export function validateResolverConfigForType(ctx: TransformerSchemaVisitStepContextProvider, typeName: string): void {
+/**
+ *
+ */
+export const syncDataSourceConfig = (): DeltaSyncConfig => ({
+  DeltaSyncTableName: joinWithEnv('-', [
+    SyncResourceIDs.syncTableName,
+    cdk.Fn.getAtt(ResourceConstants.RESOURCES.GraphQLAPILogicalID, 'ApiId'),
+  ]),
+  DeltaSyncTableTTL: 30,
+  BaseTableTTL: 43200, // 30 days
+});
+
+/**
+ *
+ */
+export const validateResolverConfigForType = (ctx: TransformerSchemaVisitStepContextProvider, typeName: string): void => {
   const resolverConfig = ctx.getResolverConfig<ResolverConfig>();
   const typeResolverConfig = resolverConfig?.models?.[typeName];
   if (typeResolverConfig && (!typeResolverConfig.ConflictDetection || !typeResolverConfig.ConflictHandler)) {
     console.warn(`Invalid resolverConfig for type ${typeName}. Using the project resolverConfig instead.`);
   }
-}
+};
 
-export function getSyncConfig(ctx: TransformerTransformSchemaStepContextProvider, typeName: string): SyncConfig | undefined {
+/**
+ *
+ */
+export const getSyncConfig = (ctx: TransformerTransformSchemaStepContextProvider, typeName: string): SyncConfig | undefined => {
   let syncConfig: SyncConfig | undefined;
 
   const resolverConfig = ctx.getResolverConfig<ResolverConfig>();
@@ -114,15 +143,19 @@ export function getSyncConfig(ctx: TransformerTransformSchemaStepContextProvider
   }
 
   return syncConfig;
-}
+};
 
-export function isLambdaSyncConfig(syncConfig: SyncConfig): syncConfig is SyncConfigLambda {
+/**
+ *
+ */
+export const isLambdaSyncConfig = (syncConfig: SyncConfig): syncConfig is SyncConfigLambda => {
   const lambdaConfigKey: keyof SyncConfigLambda = 'LambdaConflictHandler';
   if (syncConfig && syncConfig.ConflictHandler === 'LAMBDA') {
+    // eslint-disable-next-line no-prototype-builtins
     if (syncConfig.hasOwnProperty(lambdaConfigKey)) {
       return true;
     }
-    throw Error(`Invalid Lambda SyncConfig`);
+    throw Error('Invalid Lambda SyncConfig');
   }
   return false;
 }
@@ -151,26 +184,18 @@ function syncLambdaArnResource(stackManager: StackManagerProvider, name: string,
     cdk.Fn.sub(lambdaArnKey(name, region), substitutions),
     cdk.Fn.sub(lambdaArnKey(removeEnvReference(name), region), {}),
   ).toString();
-}
+};
 
-function referencesEnv(value: string): boolean {
-  return value.match(/(\${env})/) !== null;
-}
+const referencesEnv = (value: string): boolean => value.match(/(\${env})/) !== null;
 
-function lambdaArnKey(name: string, region?: string): string {
-  return region
-    ? `arn:aws:lambda:${region}:\${AWS::AccountId}:function:${name}`
-    : `arn:aws:lambda:\${AWS::Region}:\${AWS::AccountId}:function:${name}`;
-}
+const lambdaArnKey = (name: string, region?: string): string => (region
+  ? `arn:aws:lambda:${region}:\${AWS::AccountId}:function:${name}`
+  : `arn:aws:lambda:\${AWS::Region}:\${AWS::AccountId}:function:${name}`);
 
-function removeEnvReference(value: string): string {
-  return value.replace(/(-\${env})/, '');
-}
+const removeEnvReference = (value: string): string => value.replace(/(-\${env})/, '');
 
-function joinWithEnv(separator: string, listToJoin: any[]) {
-  return cdk.Fn.conditionIf(
-    ResourceConstants.CONDITIONS.HasEnvironmentParameter,
-    cdk.Fn.join(separator, [...listToJoin, cdk.Fn.ref(ResourceConstants.PARAMETERS.Env)]),
-    cdk.Fn.join(separator, listToJoin),
-  );
-}
+const joinWithEnv = (separator: string, listToJoin: any[]): cdk.ICfnRuleConditionExpression => cdk.Fn.conditionIf(
+  ResourceConstants.CONDITIONS.HasEnvironmentParameter,
+  cdk.Fn.join(separator, [...listToJoin, cdk.Fn.ref(ResourceConstants.PARAMETERS.Env)]),
+  cdk.Fn.join(separator, listToJoin),
+);
diff --git a/packages/graphql-transformer-common/src/ResourceConstants.ts b/packages/graphql-transformer-common/src/ResourceConstants.ts
index 48b9d1a494..7384898e79 100644
--- a/packages/graphql-transformer-common/src/ResourceConstants.ts
+++ b/packages/graphql-transformer-common/src/ResourceConstants.ts
@@ -1,3 +1,6 @@
+/**
+ * List of Constants
+ */
 export class ResourceConstants {
   public static NONE = 'NONE';
 
@@ -35,6 +38,7 @@ export class ResourceConstants {
     AuthCognitoUserPoolNativeClientLogicalID: 'AuthCognitoUserPoolNativeClient',
     AuthCognitoUserPoolJSClientLogicalID: 'AuthCognitoUserPoolJSClient',
   };
+
   public static PARAMETERS = {
     // cli
     Env: 'env',
@@ -85,6 +89,7 @@ export class ResourceConstants {
     // Auth
     AuthCognitoUserPoolId: 'AuthCognitoUserPoolId',
   };
+
   public static MAPPINGS = {};
   public static CONDITIONS = {
     // Environment
@@ -99,6 +104,7 @@ export class ResourceConstants {
     ShouldCreateAPIKey: 'ShouldCreateAPIKey',
     APIKeyExpirationEpochIsPositive: 'APIKeyExpirationEpochIsPositive',
   };
+
   public static OUTPUTS = {
     // AppSync
     GraphQLAPIEndpointOutput: 'GraphQLAPIEndpointOutput',
@@ -122,6 +128,7 @@ export class ResourceConstants {
     AuthCognitoUserPoolNativeClientOutput: 'AuthCognitoUserPoolNativeClientId',
     AuthCognitoUserPoolJSClientOutput: 'AuthCognitoUserPoolJSClientId',
   };
+
   public static METADATA = {};
 
   public static readonly SNIPPETS = {
diff --git a/packages/graphql-transformer-common/src/SyncResourceIDs.ts b/packages/graphql-transformer-common/src/SyncResourceIDs.ts
index 37f4716641..9e92b5bf76 100644
--- a/packages/graphql-transformer-common/src/SyncResourceIDs.ts
+++ b/packages/graphql-transformer-common/src/SyncResourceIDs.ts
@@ -1,13 +1,23 @@
 import { simplifyName } from './util';
 
+/**
+ * Constants for the DataStore resource
+ */
 export class SyncResourceIDs {
-  public static syncDataSourceID: string = 'DataStore';
-  public static syncTableName: string = 'AmplifyDataStore';
-  public static syncPrimaryKey: string = 'ds_pk';
-  public static syncRangeKey: string = 'ds_sk';
-  public static syncIAMRoleID: string = 'DataStoreIAMRole'
-  public static syncIAMRoleName: string = 'AmplifyDataStoreIAMRole';
-  public static syncFunctionRoleName: string = 'DataStoreLambdaRole';
+  public static syncDataSourceID = 'DataStore';
+  public static syncTableName = 'AmplifyDataStore';
+  public static syncPrimaryKey = 'ds_pk';
+  public static syncRangeKey = 'ds_sk';
+  public static syncGSIName = 'deltaSyncGSI';
+  public static syncGSIPartitionKey = 'gsi_ds_pk';
+  public static syncGSISortKey = 'gsi_ds_sk';
+  public static syncIAMRoleID = 'DataStoreIAMRole'
+  public static syncIAMRoleName = 'AmplifyDataStoreIAMRole';
+  public static syncFunctionRoleName = 'DataStoreLambdaRole';
+
+  /**
+   * Returns the syncFunctionID
+   */
   public static syncFunctionID(name: string, region?: string): string {
     return `${simplifyName(name)}${simplifyName(region || '')}Role`;
   }