Poll workers of a partitioned step with a database query

spring-batch-core/src/main/java/org/springframework/batch/core/BatchStatus.java

@@ -16,6 +16,8 @@
 
 package org.springframework.batch.core;
 
+import java.util.Set;
+
 /**
  * Enumeration representing the status of an execution.
  *
@@ -71,6 +73,8 @@ public enum BatchStatus {
 	 */
 	UNKNOWN;
 
+	public static final Set<BatchStatus> RUNNING_STATUSES = Set.of(STARTING, STARTED, STOPPING);
+
 	/**
 	 * Convenience method to return the higher value status of the statuses passed to the
 	 * method.
@@ -87,7 +91,7 @@ public static BatchStatus max(BatchStatus status1, BatchStatus status2) {
 	 * @return true if the status is STARTING, STARTED, STOPPING
 	 */
 	public boolean isRunning() {
-		return this == STARTING || this == STARTED || this == STOPPING;
+		return RUNNING_STATUSES.contains(this);
 	}
 
 	/**

spring-batch-core/src/main/java/org/springframework/batch/core/explore/JobExplorer.java

@@ -18,6 +18,7 @@
 import java.util.List;
 import java.util.Set;
 
+import org.springframework.batch.core.BatchStatus;
 import org.springframework.batch.core.JobExecution;
 import org.springframework.batch.core.JobInstance;
 import org.springframework.batch.core.JobParameters;
@@ -87,6 +88,14 @@ default JobInstance getLastJobInstance(String jobName) {
 	@Nullable
 	StepExecution getStepExecution(@Nullable Long jobExecutionId, @Nullable Long stepExecutionId);
 
+	/**
+	 * Find {@link StepExecution}s by IDs and parent {@link JobExecution} ID
+	 * @param jobExecutionId given job execution id
+	 * @param stepExecutionIds given step execution ids
+	 * @return collection of {@link StepExecution}
+	 */
+	Set<StepExecution> getStepExecutions(Long jobExecutionId, Set<Long> stepExecutionIds);
+
 	/**
 	 * @param instanceId {@link Long} The ID for the {@link JobInstance} to obtain.
 	 * @return the {@code JobInstance} that has this ID, or {@code null} if not found.
@@ -170,4 +179,13 @@ default JobExecution getLastJobExecution(JobInstance jobInstance) {
 	 */
 	long getJobInstanceCount(@Nullable String jobName) throws NoSuchJobException;
 
+	/**
+	 * Retrieve number of step executions that match the step execution ids and the batch
+	 * statuses
+	 * @param stepExecutionIds given step execution ids
+	 * @param matchingBatchStatuses given batch statuses to match against
+	 * @return number of {@link StepExecution} matching the criteria
+	 */
+	long getStepExecutionCount(Set<Long> stepExecutionIds, Set<BatchStatus> matchingBatchStatuses);
+
 }

spring-batch-core/src/main/java/org/springframework/batch/core/explore/support/SimpleJobExplorer.java

@@ -16,6 +16,7 @@
 
 package org.springframework.batch.core.explore.support;
 
+import org.springframework.batch.core.BatchStatus;
 import org.springframework.batch.core.JobExecution;
 import org.springframework.batch.core.JobInstance;
 import org.springframework.batch.core.JobParameters;
@@ -147,6 +148,19 @@ public StepExecution getStepExecution(@Nullable Long jobExecutionId, @Nullable L
 		return stepExecution;
 	}
 
+	@Nullable
+	@Override
+	public Set<StepExecution> getStepExecutions(Long jobExecutionId, Set<Long> stepExecutionIds) {
+		JobExecution jobExecution = jobExecutionDao.getJobExecution(jobExecutionId);
+		if (jobExecution == null) {
+			return null;
+		}
+		getJobExecutionDependencies(jobExecution);
+		Set<StepExecution> stepExecutions = stepExecutionDao.getStepExecutions(jobExecution, stepExecutionIds);
+		stepExecutions.forEach(this::getStepExecutionDependencies);
+		return stepExecutions;
+	}
+
 	@Nullable
 	@Override
 	public JobInstance getJobInstance(@Nullable Long instanceId) {
@@ -180,6 +194,14 @@ public long getJobInstanceCount(@Nullable String jobName) throws NoSuchJobExcept
 		return jobInstanceDao.getJobInstanceCount(jobName);
 	}
 
+	@Override
+	public long getStepExecutionCount(Set<Long> stepExecutionIds, Set<BatchStatus> matchingBatchStatuses) {
+		if (stepExecutionIds.isEmpty() || matchingBatchStatuses.isEmpty()) {
+			return 0;
+		}
+		return stepExecutionDao.countStepExecutions(stepExecutionIds, matchingBatchStatuses);
+	}
+
 	/**
 	 * @return instance of {@link JobInstanceDao}.
 	 * @since 5.1

spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/AbstractJdbcBatchMetadataDao.java

@@ -17,6 +17,9 @@
 package org.springframework.batch.core.repository.dao;
 
 import java.sql.Types;
+import java.util.Collection;
+import java.util.Map;
+import java.util.stream.Collectors;
 
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.jdbc.core.JdbcOperations;
@@ -51,6 +54,14 @@ protected String getQuery(String base) {
 		return StringUtils.replace(base, "%PREFIX%", tablePrefix);
 	}
 
+	protected String getQuery(String base, Map<String, Collection<?>> collectionParams) {
+		String query = getQuery(base);
+		for (Map.Entry<String, Collection<?>> collectionParam : collectionParams.entrySet()) {
+			query = createParameterizedQuery(query, collectionParam.getKey(), collectionParam.getValue());
+		}
+		return query;
+	}
+
 	protected String getTablePrefix() {
 		return tablePrefix;
 	}
@@ -80,6 +91,18 @@ public void setClobTypeToUse(int clobTypeToUse) {
 		this.clobTypeToUse = clobTypeToUse;
 	}
 
+	/**
+	 * Replaces a given placeholder with a number of parameters (i.e. "?").
+	 * @param sqlTemplate given sql template
+	 * @param placeholder placeholder that is being used for parameters
+	 * @param parameters collection of parameters with variable size
+	 * @return sql query replaced with a number of parameters
+	 */
+	private static String createParameterizedQuery(String sqlTemplate, String placeholder, Collection<?> parameters) {
+		String params = parameters.stream().map(p -> "?").collect(Collectors.joining(", "));
+		return sqlTemplate.replace(placeholder, params);
+	}
+
 	@Override
 	public void afterPropertiesSet() throws Exception {
 		Assert.state(jdbcTemplate != null, "JdbcOperations is required");

spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/JdbcStepExecutionDao.java

@@ -27,8 +27,11 @@
 import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
+import java.util.stream.Stream;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -93,6 +96,16 @@ public class JdbcStepExecutionDao extends AbstractJdbcBatchMetadataDao implement
 
 	private static final String GET_STEP_EXECUTION = GET_RAW_STEP_EXECUTIONS + " AND STEP_EXECUTION_ID = ?";
 
+	private static final String GET_STEP_EXECUTIONS_BY_IDS = GET_RAW_STEP_EXECUTIONS
+			+ " and STEP_EXECUTION_ID IN (%STEP_EXECUTION_IDS%)";
+
+	private static final String COUNT_STEP_EXECUTIONS_BY_IDS_AND_STATUSES = """
+			SELECT COUNT(*)
+			   FROM %PREFIX%STEP_EXECUTION SE
+			   WHERE SE.STEP_EXECUTION_ID IN (%STEP_EXECUTION_IDS%)
+			   AND SE.STATUS IN (%STEP_STATUSES%)
+			""";
+
 	private static final String GET_LAST_STEP_EXECUTION = """
 			SELECT SE.STEP_EXECUTION_ID, SE.STEP_NAME, SE.START_TIME, SE.END_TIME, SE.STATUS, SE.COMMIT_COUNT, SE.READ_COUNT, SE.FILTER_COUNT, SE.WRITE_COUNT, SE.EXIT_CODE, SE.EXIT_MESSAGE, SE.READ_SKIP_COUNT, SE.WRITE_SKIP_COUNT, SE.PROCESS_SKIP_COUNT, SE.ROLLBACK_COUNT, SE.LAST_UPDATED, SE.VERSION, SE.CREATE_TIME, JE.JOB_EXECUTION_ID, JE.START_TIME, JE.END_TIME, JE.STATUS, JE.EXIT_CODE, JE.EXIT_MESSAGE, JE.CREATE_TIME, JE.LAST_UPDATED, JE.VERSION
 			FROM %PREFIX%JOB_EXECUTION JE
@@ -337,6 +350,16 @@ public StepExecution getStepExecution(JobExecution jobExecution, Long stepExecut
 		}
 	}
 
+	@Override
+	@Nullable
+	public Set<StepExecution> getStepExecutions(JobExecution jobExecution, Set<Long> stepExecutionIds) {
+		List<StepExecution> executions = getJdbcTemplate().query(
+				getQuery(GET_STEP_EXECUTIONS_BY_IDS, Map.of("%STEP_EXECUTION_IDS%", stepExecutionIds)),
+				new StepExecutionRowMapper(jobExecution),
+				Stream.concat(Stream.of(jobExecution.getId()), stepExecutionIds.stream()).toArray(Object[]::new));
+		return Set.copyOf(executions);
+	}
+
 	@Override
 	public StepExecution getLastStepExecution(JobInstance jobInstance, String stepName) {
 		List<StepExecution> executions = getJdbcTemplate().query(getQuery(GET_LAST_STEP_EXECUTION), (rs, rowNum) -> {
@@ -360,6 +383,16 @@ public StepExecution getLastStepExecution(JobInstance jobInstance, String stepNa
 		}
 	}
 
+	@Override
+	public long countStepExecutions(Collection<Long> stepExecutionIds, Collection<BatchStatus> matchingBatchStatuses) {
+		return getJdbcTemplate().queryForObject(
+				getQuery(COUNT_STEP_EXECUTIONS_BY_IDS_AND_STATUSES,
+						Map.of("%STEP_EXECUTION_IDS%", stepExecutionIds, "%STEP_STATUSES%", matchingBatchStatuses)),
+				Long.class,
+				Stream.concat(stepExecutionIds.stream(), matchingBatchStatuses.stream().map(BatchStatus::name))
+					.toArray(Object[]::new));
+	}
+
 	@Override
 	public void addStepExecutions(JobExecution jobExecution) {
 		getJdbcTemplate().query(getQuery(GET_STEP_EXECUTIONS), new StepExecutionRowMapper(jobExecution),

spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/MongoStepExecutionDao.java

@@ -20,7 +20,10 @@
 import java.util.Comparator;
 import java.util.List;
 import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
 
+import org.springframework.batch.core.BatchStatus;
 import org.springframework.batch.core.JobExecution;
 import org.springframework.batch.core.JobInstance;
 import org.springframework.batch.core.StepExecution;
@@ -95,6 +98,17 @@ public StepExecution getStepExecution(JobExecution jobExecution, Long stepExecut
 		return stepExecution != null ? this.stepExecutionConverter.toStepExecution(stepExecution, jobExecution) : null;
 	}
 
+	@Override
+	public Set<StepExecution> getStepExecutions(JobExecution jobExecution, Set<Long> stepExecutionIds) {
+		Query query = query(where("stepExecutionId").in(stepExecutionIds));
+		List<org.springframework.batch.core.repository.persistence.StepExecution> stepExecutions = this.mongoOperations
+			.find(query, org.springframework.batch.core.repository.persistence.StepExecution.class,
+					STEP_EXECUTIONS_COLLECTION_NAME);
+		return stepExecutions.stream()
+			.map(stepExecution -> this.stepExecutionConverter.toStepExecution(stepExecution, jobExecution))
+			.collect(Collectors.toSet());
+	}
+
 	@Override
 	public StepExecution getLastStepExecution(JobInstance jobInstance, String stepName) {
 		// TODO optimize the query
@@ -160,4 +174,12 @@ public long countStepExecutions(JobInstance jobInstance, String stepName) {
 		return count;
 	}
 
+	@Override
+	public long countStepExecutions(Collection<Long> stepExecutionIds, Collection<BatchStatus> matchingBatchStatuses) {
+		Query query = query(where("jobExecutionId").is(stepExecutionIds).and("status").in(matchingBatchStatuses));
+		return this.mongoOperations.count(query,
+				org.springframework.batch.core.repository.persistence.StepExecution.class,
+				STEP_EXECUTIONS_COLLECTION_NAME);
+	}
+
 }

spring-batch-core/src/main/java/org/springframework/batch/core/repository/dao/StepExecutionDao.java

@@ -17,7 +17,9 @@
 package org.springframework.batch.core.repository.dao;
 
 import java.util.Collection;
+import java.util.Set;
 
+import org.springframework.batch.core.BatchStatus;
 import org.springframework.batch.core.JobExecution;
 import org.springframework.batch.core.JobInstance;
 import org.springframework.batch.core.StepExecution;
@@ -62,6 +64,15 @@ public interface StepExecutionDao {
 	@Nullable
 	StepExecution getStepExecution(JobExecution jobExecution, Long stepExecutionId);
 
+	/**
+	 * Get a collection of {@link StepExecution} matching job execution and step execution
+	 * ids.
+	 * @param jobExecution the parent job execution
+	 * @param stepExecutionIds the step execution ids
+	 * @return collection of {@link StepExecution}
+	 */
+	Set<StepExecution> getStepExecutions(JobExecution jobExecution, Set<Long> stepExecutionIds);
+
 	/**
 	 * Retrieve the last {@link StepExecution} for a given {@link JobInstance} ordered by
 	 * creation time and then id.
@@ -91,6 +102,15 @@ default long countStepExecutions(JobInstance jobInstance, String stepName) {
 		throw new UnsupportedOperationException();
 	}
 
+	/**
+	 * Count {@link StepExecution} that match the ids and statuses of them - avoid loading
+	 * them into memory
+	 * @param stepExecutionIds given step execution ids
+	 * @param matchingBatchStatuses
+	 * @return the count of matching steps
+	 */
+	long countStepExecutions(Collection<Long> stepExecutionIds, Collection<BatchStatus> matchingBatchStatuses);
+
 	/**
 	 * Delete the given step execution.
 	 * @param stepExecution the step execution to delete

spring-batch-core/src/test/java/org/springframework/batch/core/launch/support/CommandLineJobRunnerTests.java

@@ -551,6 +551,11 @@ public StepExecution getStepExecution(@Nullable Long jobExecutionId, @Nullable L
 			throw new UnsupportedOperationException();
 		}
 
+		@Override
+		public Set<StepExecution> getStepExecutions(Long jobExecutionId, Set<Long> stepExecutionIds) {
+			return Set.of();
+		}
+
 		@Override
 		public List<String> getJobNames() {
 			throw new UnsupportedOperationException();
@@ -579,6 +584,11 @@ public long getJobInstanceCount(@Nullable String jobName) throws NoSuchJobExcept
 			}
 		}
 
+		@Override
+		public long getStepExecutionCount(Set<Long> stepExecutionIds, Set<BatchStatus> matchingBatchStatuses) {
+			return 0;
+		}
+
 	}
 
 	public static class StubJobParametersConverter implements JobParametersConverter {

spring-batch-core/src/test/java/org/springframework/batch/core/repository/support/SimpleJobRepositoryTests.java

@@ -202,7 +202,7 @@ void testSaveStepExecutionSetsLastUpdated() {
 		assertNotNull(stepExecution.getLastUpdated());
 
 		LocalDateTime lastUpdated = stepExecution.getLastUpdated();
-		assertTrue(lastUpdated.isAfter(before));
+		assertFalse(lastUpdated.isBefore(before));
 	}
 
 	@Test
@@ -236,7 +236,7 @@ void testUpdateStepExecutionSetsLastUpdated() {
 		assertNotNull(stepExecution.getLastUpdated());
 
 		LocalDateTime lastUpdated = stepExecution.getLastUpdated();
-		assertTrue(lastUpdated.isAfter(before));
+		assertFalse(lastUpdated.isBefore(before));
 	}
 
 	@Test

spring-batch-integration/src/main/java/org/springframework/batch/integration/partition/MessageChannelPartitionHandler.java

@@ -28,7 +28,7 @@
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
-import org.springframework.batch.core.JobExecution;
+import org.springframework.batch.core.BatchStatus;
 import org.springframework.batch.core.Step;
 import org.springframework.batch.core.StepExecution;
 import org.springframework.batch.core.explore.JobExplorer;
@@ -251,25 +251,20 @@ protected Set<StepExecution> doHandle(StepExecution managerStepExecution,
 
 	private Set<StepExecution> pollReplies(final StepExecution managerStepExecution, final Set<StepExecution> split)
 			throws Exception {
-		Set<Long> partitionStepExecutionIds = split.stream().map(StepExecution::getId).collect(Collectors.toSet());
 
 		Callable<Set<StepExecution>> callback = () -> {
-			JobExecution jobExecution = jobExplorer.getJobExecution(managerStepExecution.getJobExecutionId());
-			Set<StepExecution> finishedStepExecutions = jobExecution.getStepExecutions()
-				.stream()
-				.filter(stepExecution -> partitionStepExecutionIds.contains(stepExecution.getId()))
-				.filter(stepExecution -> !stepExecution.getStatus().isRunning())
-				.collect(Collectors.toSet());
-
-			if (logger.isDebugEnabled()) {
-				logger.debug(String.format("Currently waiting on %s partitions to finish", split.size()));
-			}
-
-			if (finishedStepExecutions.size() == split.size()) {
-				return finishedStepExecutions;
+			Set<Long> currentStepExecutionIds = split.stream().map(StepExecution::getId).collect(Collectors.toSet());
+			long runningStepExecutions = jobExplorer.getStepExecutionCount(currentStepExecutionIds,
+					BatchStatus.RUNNING_STATUSES);
+			if (runningStepExecutions > 0 && !split.isEmpty()) {
+				if (logger.isDebugEnabled()) {
+					logger.debug(String.format("Currently waiting on %s out of %s partitions to finish",
+							runningStepExecutions, split.size()));
+				}
+				return null;
 			}
 			else {
-				return null;
+				return jobExplorer.getStepExecutions(managerStepExecution.getJobExecutionId(), currentStepExecutionIds);
 			}
 		};