Updated documentation and test around query plan caching (Azure#28010)

Author: kushagraThapar

sdk/cosmos/azure-cosmos/src/main/java/com/azure/cosmos/implementation/Configs.java

@@ -238,7 +238,7 @@ public static String getEnvironmentName() {
     }
 
     public static boolean isQueryPlanCachingEnabled() {
-        // Queryplan caching will be disabled by default
+        // Queryplan caching is enabled by default
         return getJVMConfigAsBoolean(QUERYPLAN_CACHING_ENABLED, true);
     }
 

sdk/cosmos/azure-spring-data-cosmos-test/src/test/java/com/azure/spring/data/cosmos/core/CosmosTemplatePartitionIT.java

@@ -93,8 +93,7 @@ public class CosmosTemplatePartitionIT {
     @Before
     public void setUp() throws ClassNotFoundException {
         if (cosmosTemplate == null) {
-            //  Enable Query plan caching for testing
-            System.setProperty("COSMOS.QUERYPLAN_CACHING_ENABLED", "true");
+            //  Query plan caching is enabled by default
             CosmosAsyncClient client = CosmosFactory.createCosmosAsyncClient(cosmosClientBuilder);
             cosmosFactory = new CosmosFactory(client, TestConstants.DB_NAME);
             final CosmosMappingContext mappingContext = new CosmosMappingContext();

sdk/cosmos/azure-spring-data-cosmos-test/src/test/java/com/azure/spring/data/cosmos/core/ReactiveCosmosTemplatePartitionIT.java

@@ -79,8 +79,7 @@ public class ReactiveCosmosTemplatePartitionIT {
     @Before
     public void setUp() throws ClassNotFoundException {
         if (cosmosTemplate == null) {
-            //  Enable Query plan caching for testing
-            System.setProperty("COSMOS.QUERYPLAN_CACHING_ENABLED", "true");
+            //  Query plan caching is enabled by default
             CosmosAsyncClient client = CosmosFactory.createCosmosAsyncClient(cosmosClientBuilder);
             cosmosFactory = new CosmosFactory(client, TestConstants.DB_NAME);
 

sdk/cosmos/azure-spring-data-cosmos/README.md

@@ -307,7 +307,7 @@ public interface UserRepository extends CosmosRepository<User, String> {
 - `findByFirstName` method is custom query method, it will find items per firstName.
 
 #### Query Plan Caching
-When query plan caching is enabled, custom query methods like `findByFirstName(String firstName)` where `firstName` is the partition key will result in lower query execution time. Query plan caching can be enabled by setting the `COSMOS.QUERYPLAN_CACHING_ENABLED` System property to 'true'. Currently, query plan caching is only supported for custom query methods targeting a single partition.
+Spring repository query APIs like `findByFirstName(String firstName)` where `firstName` is the partition or annotated queries containing partition key will result in lower query execution time because of query plan caching. Currently, query plan caching is only supported for query methods targeting a single partition.
 
 #### QueryAnnotation : Using annotated queries in repositories
 Azure spring data cosmos supports specifying annotated queries in the repositories using `@Query`.