Merge pull request #1 from ericharmeling/no-follower-reads

[JDBC] No follower reads + other changes

Author: Eric Harmeling

roach-data-jdbc/src/main/java/io/roach/data/jdbc/AccountController.java

@@ -84,7 +84,6 @@ public ResponseEntity<RepresentationModel> index() {
      */
     @GetMapping("/account")
     @Transactional(propagation = REQUIRES_NEW)
-    @TimeTravel // We dont need the result to be authoritative, so any follower replica can service the read
     public HttpEntity<PagedModel<AccountModel>> listAccounts(
             @PageableDefault(size = 5, direction = Sort.Direction.ASC) Pageable page) {
         return ResponseEntity

roach-data-jdbc/src/main/java/io/roach/data/jdbc/AccountRepository.java

@@ -14,8 +14,6 @@
 /**
  * The main account repository, notice there's no implementation needed since its auto-proxied by
  * spring-data.
- * <p>
- * Should have extended PagingAndSortingRepository in normal cases.
  */
 @Repository
 @Transactional(propagation = MANDATORY)

roach-data-jdbc/src/main/java/io/roach/data/jdbc/JdbcApplication.java

@@ -14,14 +14,11 @@
 import org.slf4j.LoggerFactory;
 import org.springframework.boot.CommandLineRunner;
 import org.springframework.boot.WebApplicationType;
-import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.builder.SpringApplicationBuilder;
-import org.springframework.context.annotation.ComponentScan;
-import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.EnableAspectJAutoProxy;
 import org.springframework.core.Ordered;
 import org.springframework.data.jdbc.repository.config.EnableJdbcRepositories;
-import org.springframework.data.web.config.EnableSpringDataWebSupport;
 import org.springframework.hateoas.Link;
 import org.springframework.hateoas.config.EnableHypermediaSupport;
 import org.springframework.http.HttpEntity;
@@ -33,14 +30,11 @@
 /**
  * Spring boot server application using spring-data-jdbc for data access.
  */
-@EnableAutoConfiguration
 @EnableHypermediaSupport(type = EnableHypermediaSupport.HypermediaType.HAL)
 @EnableJdbcRepositories
 @EnableAspectJAutoProxy(proxyTargetClass = true)
-@EnableSpringDataWebSupport
 @EnableTransactionManagement(order = Ordered.LOWEST_PRECEDENCE - 1) // Bump up one level to enable extra advisors
-@Configuration
-@ComponentScan
+@SpringBootApplication
 public class JdbcApplication implements CommandLineRunner {
     protected static final Logger logger = LoggerFactory.getLogger(JdbcApplication.class);
 

roach-data-jdbc/src/main/java/io/roach/data/jdbc/PagedAccountRepositoryImpl.java

@@ -10,7 +10,7 @@
 import static org.springframework.transaction.annotation.Propagation.MANDATORY;
 
 @Repository
-// @Transactional is not needed but here for clarity since we want repos to always be called from a tx context
+// @Transactional annotation here to emphasise that repositories should always be called within an existing transaction context
 @Transactional(propagation = MANDATORY)
 public class PagedAccountRepositoryImpl implements PagedAccountRepository {
     @Autowired

roach-data-jdbc/src/main/java/io/roach/data/jdbc/TimeTravel.java

@@ -38,10 +38,6 @@ public class TransactionHintsAspect {
     public void anyTransactionBoundaryOperation(Transactional transactional) {
     }
 
-    @Pointcut("execution(* io.roach..*(..)) && @annotation(followerRead)")
-    public void anyFollowerReadOperation(TimeTravel followerRead) {
-    }
-
     @Around(value = "anyTransactionBoundaryOperation(transactional)",
             argNames = "pjp,transactional")
     public Object setTransactionAttributes(ProceedingJoinPoint pjp, Transactional transactional)
@@ -64,21 +60,4 @@ public Object setTransactionAttributes(ProceedingJoinPoint pjp, Transactional tr
 
         return pjp.proceed();
     }
-
-    @Around(value = "anyFollowerReadOperation(timeTravel)",
-            argNames = "pjp,timeTravel")
-    public Object setTimeTravelAttributes(ProceedingJoinPoint pjp, TimeTravel timeTravel)
-            throws Throwable {
-        Assert.isTrue(TransactionSynchronizationManager.isActualTransactionActive(), "TX not active");
-
-        logger.info("Providing {} via follower read", pjp.getSignature().toShortString());
-
-        if (timeTravel.value() >= 0) {
-            jdbcTemplate.update("SET TRANSACTION AS OF SYSTEM TIME INTERVAL '" + timeTravel.value() + "'");
-        } else {
-            jdbcTemplate.execute("SET TRANSACTION AS OF SYSTEM TIME experimental_follower_read_timestamp()");
-        }
-
-        return pjp.proceed();
-    }
 }