Unable to query after a successful connection for a period of time in GridDB

Question

I’m experiencing an issue with GridDB where the program becomes blocked during a query and logs a Sending heartbeat It seems that the issue is related to the connection management or the GridDB cluster's responsiveness

Following are the logs

select * where (name='message-count') AND count > 0 AND  timestamp < TIMESTAMP('2022-12-30T11:02:01.567+0800') AND timestamp > TIMESTAMP('2022-12-29T11:02:01.567+0800') order by timestamp
Sending heartbeat (statement=CREATE_SESSION, address=/192.168.1.134:10001, partition=7, statementId=15, elapsedMillis=10000)
Sending heartbeat (statement=CREATE_SESSION, address=/192.168.1.134:10001, partition=7, statementId=15, elapsedMillis=20004)

This may be a concurrency problem. I try the following code to reproduce this problem

package com.griddb.client;
import cn.hutool.core.date.DateField;
import cn.hutool.core.date.DateTime;
import cn.hutool.core.date.DateUtil;
import com.toshiba.mwcloud.gs.*;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.*;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.FutureTask;
import static cn.hutool.core.date.DatePattern.UTC_MS_WITH_ZONE_OFFSET_PATTERN;
public class GriddbClient {
    static class Iot {
        @RowKey
        Date timestamp;
        double data;
        double temperature;
    @Override
    public String toString() {
        return "Iot{" +
                "timestamp=" + timestamp +
                ", data=" + data +
                ", temperature=" + temperature +
                '}';
    }
}

public static void main(String[] args) throws Exception{
    //bulkInsertData();
    concurrentQuery();
}

/**
 * Bulk Insert Data
 * @throws Exception
 */
public static void bulkInsertData() throws Exception{
    Properties props = new Properties();
    props.setProperty("host", "192.168.1.134");
    props.setProperty("port", "10001");
    props.setProperty("clusterName", "myCluster");
    props.setProperty("user", "admin");
    props.setProperty("password", "admin");
    props.setProperty("database","public");
    props.setProperty("transactionTimeout","5000");
    props.setProperty("failoverTimeout","5000");
    GridStore store = GridStoreFactory.getInstance().getGridStore(props);
    TimeSeries<test5.Iot> lctime = store.putTimeSeries("lctime", test5.Iot.class);
    lctime.createIndex("data");
    lctime.setAutoCommit(false);
    DateTime now = DateTime.now();
    for(int i=0;i<360;i++){
        DateTime dateTime = now.offset(DateField.MINUTE, 1);
        test5.Iot item1=new test5.Iot();
        item1.timestamp=dateTime;
        item1.data=i;
        item1.temperature=i;
        lctime.put(dateTime,item1);
        System.out.println(DateUtil.formatDateTime(dateTime));
    }



    lctime.commit();
    System.out.println("succcess");
    store.close();
}

/**
 * Concurrent query
 * @throws Exception
 */
public static void concurrentQuery() throws Exception{
    int concurrency=10;
    final Date start=getDate("2022-11-20");
    final Date end=getDate("2022-12-30");
    Set<String> culume=new HashSet<String>();
    culume.add("timestamp");
    culume.add("data");
    culume.add("temperature");

    Properties props = new Properties();
    props.setProperty("host", "192.168.1.134");
    props.setProperty("port", "10001");
    props.setProperty("clusterName", "myCluster");
    props.setProperty("user", "admin");
    props.setProperty("password", "admin");
    props.setProperty("database","public");
    props.setProperty("transactionTimeout","5000");
    props.setProperty("failoverTimeout","5000");
    final GridStore store = GridStoreFactory.getInstance().getGridStore(props);

    ExecutorService executorService = Executors.newFixedThreadPool(20);
    List<FutureTask<List<test5.Iot>>> tasks=new ArrayList<FutureTask<List<test5.Iot>>>();

    for(int i=0;i<concurrency;i++){
        FutureTask<List<test5.Iot>> task1=new FutureTask<List<test5.Iot>>(new Callable<List<test5.Iot>>() {
            public List<test5.Iot> call() throws Exception {
                return createTask(start,end,store);
            }
        });
        tasks.add(task1);
        executorService.submit(tasks.get(tasks.size()-1));
    }

    for(FutureTask<List<test5.Iot>> item:tasks){
        List<test5.Iot> iots = item.get();
        System.out.println(iots.size());
    }
    store.close();
}

private static List<test5.Iot> createTask(Date start, Date end, GridStore store) throws Exception{
    TimeSeries<test5.Iot> lctime = store.getTimeSeries("lctime", test5.Iot.class);
    String tql="select * where timestamp > TIMESTAMP('" + formatDate(start) + "') and timestamp < TIMESTAMP('" + formatDate(end) + "')";
    System.out.println(tql);
    RowSet<test5.Iot> query = lctime.query(tql, test5.Iot.class).fetch();
    List<test5.Iot> iots=new ArrayList<test5.Iot>();
    while (query.hasNext()){
        test5.Iot next = query.next();
        System.out.println(next.toString());
        iots.add(next);
    }
    lctime.close();
    return iots;
}

private static Date getDate(String dataStr) throws Exception{
    DateFormat dateFormat1 = new SimpleDateFormat("yyyy-MM-dd");
    return dateFormat1.parse(dataStr);
}

private static String formatDate(Date date){
    return DateUtil.format(date,UTC_MS_WITH_ZONE_OFFSET_PATTERN);
}

}