added tests for concurrent copy

Author: chernser

clickhouse-client/src/test/java/com/clickhouse/client/ClickHouseRequestTest.java

@@ -11,11 +11,17 @@
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Properties;
+import java.util.Set;
 import java.util.UUID;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
 
 import org.testng.Assert;
 import org.testng.annotations.Test;
@@ -654,4 +660,35 @@ public void testMutation() {
         Assert.assertEquals(request.getQuery(), expectedSql);
         Assert.assertEquals(request.getStatements().get(0), expectedSql);
     }
+
+    @Test
+    public void testConcurrentUse() {
+        ClickHouseRequest<?> request = ClickHouseClient.newInstance().read(ClickHouseNode.builder().build());
+        Assert.assertNotNull(request);
+
+        ScheduledExecutorService executor = Executors.newScheduledThreadPool(3);
+
+        final List<ClickHouseRequest<?>> sealedRequests = new ArrayList<>();
+
+        for (int i = 0; i < 3; i++) {
+            executor.scheduleWithFixedDelay(() -> {
+                String queryID = UUID.randomUUID().toString();
+//                System.out.println(System.currentTimeMillis() + "  Thread " + Thread.currentThread().getId() + " qId: " + queryID);
+                sealedRequests.add(request.query("select 1", queryID).seal());
+            }, 100, 100, TimeUnit.MILLISECONDS);
+        }
+
+        try {
+            Thread.sleep(1000);
+        } catch (InterruptedException e) {
+            Assert.fail("Thread sleep interrupted");
+        }
+        executor.shutdown();
+        final Set<String> queryIDs = new HashSet<>();
+        for (ClickHouseRequest<?> r : sealedRequests) {
+//            System.out.println(queryIDs);
+            Assert.assertTrue(queryIDs.add(r.getQueryId().get()), "Query ID should be unique: " +
+                    r.getQueryId().get());
+        }
+    }
 }