content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package org.apache.cassandra.io.sstable;
  
  import java.io.IOException;
  import java.nio.file.Paths;
  import java.util.concurrent.CountDownLatch;
  import java.util.concurrent.ExecutorService;
  import java.util.concurrent.Executors;
  import java.util.concurrent.TimeUnit;
  import java.util.concurrent.atomic.AtomicInteger;
  import java.util.concurrent.atomic.AtomicReference;
  
  import org.junit.Rule;
  import org.junit.Test;
  import org.junit.rules.TemporaryFolder;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import org.apache.cassandra.cql3.CQLTester;
  import org.apache.cassandra.dht.Murmur3Partitioner;
  import org.apache.cassandra.io.util.File;
  import org.apache.cassandra.schema.Schema;
  import org.assertj.core.description.Description;
  
  import static org.assertj.core.api.Assertions.assertThat;
  
  /**
   * Tests modifications to the Schema in the {@link CQLSSTableWriter} class while other Schema modifications are
   * occurring concurrently
   */
  public class CQLSSTableWriterConcurrencyTest extends CQLTester
  {
      private static final Logger LOGGER = LoggerFactory.getLogger(CQLSSTableWriterConcurrencyTest.class);
      @Rule
      public TemporaryFolder tempFolder = new TemporaryFolder();
  
      @Test
      public void testConcurrentSchemaModification() throws InterruptedException, IOException
      {
          String schema = "CREATE TABLE %s ("
                          + "  k int PRIMARY KEY,"
                          + "  v1 text,"
                          + "  v2 int"
                          + ")";
  
          int nThreads = 20;
          ExecutorService pool = Executors.newFixedThreadPool(nThreads);
          CountDownLatch latch = new CountDownLatch(nThreads);
          AtomicInteger errorCount = new AtomicInteger();
  
          // Prepare all the variables required for the test
          String[] tableNames = new String[nThreads];
          String[] fullQueries = new String[nThreads];
          String[] insertStatements = new String[nThreads];
          File[] dataDirs = new File[nThreads];
          String baseDataDir = tempFolder.newFolder().getAbsolutePath();
  
          AtomicReference<String> errors = new AtomicReference<>("");
          for (int i = 0; i < nThreads; i++)
          {
              tableNames[i] = String.format("table_%02d", i);
              fullQueries[i] = String.format(schema, KEYSPACE + '.' + tableNames[i]);
              LOGGER.info(fullQueries[i]);
  
              if (i % 2 != 0)
              {
                  // dataDir and insert statement are only needed for the CQLSSTableWriter class
                  dataDirs[i] = new File(Paths.get(baseDataDir, KEYSPACE, tableNames[i]));
                  assert dataDirs[i].tryCreateDirectories();
                  insertStatements[i] = String.format("INSERT INTO %s.%s (k, v1, v2) VALUES (?, ?, ?)", KEYSPACE, tableNames[i]);
              }
  
              final int finalI = i;
              pool.submit(() -> {
                  try
                  {
                      latch.countDown();
                      latch.await();
  
                      // Invoke all schema modifications roughly at the same time
                      if (finalI % 2 == 0)
                      {
                          schemaChange(fullQueries[finalI]);
                          // If another thread modified the Schema without the proper synchronization, it's possible
                          // that the table metadata was swapped out and calling the Keyspace#getColumnFamilyStore
                          // method will produce an IllegalArgumentException
                          Schema.instance.getKeyspaceInstance(KEYSPACE).getColumnFamilyStore(tableNames[finalI]);
                      }
                      else
                      {
                          CQLSSTableWriter.builder()
                                          .inDirectory(dataDirs[finalI])
                                          .forTable(fullQueries[finalI])
                                          .withPartitioner(Murmur3Partitioner.instance)
                                          .using(insertStatements[finalI])
                                          .build();
                      }
                  }
                  catch (Throwable throwable)
                  {
                      LOGGER.error("Error while processing element number {}", finalI, throwable);
                      errors.updateAndGet(s -> s + "\n" + throwable.getMessage());
                      errorCount.incrementAndGet();
                  }
              });
          }
  
          pool.shutdown();
          if (!pool.awaitTermination(1, TimeUnit.MINUTES))
          {
              LOGGER.warn("Unable to close executor pool after 1 minute");
          }
          int count = errorCount.get();
          assertThat(count).isEqualTo(0).describedAs(new Description()
          {
              public String value()
              {
                  return String.format("Caught %d errors: %s", count, errors.get());
              }
          });
      }
  }
  