diff options
Diffstat (limited to 'examples_java/src/persist/txn')
| -rw-r--r-- | examples_java/src/persist/txn/PayloadDataEntity.java | 33 | ||||
| -rw-r--r-- | examples_java/src/persist/txn/StoreWriter.java | 176 | ||||
| -rw-r--r-- | examples_java/src/persist/txn/TxnGuideDPL.java | 162 |
3 files changed, 371 insertions, 0 deletions
diff --git a/examples_java/src/persist/txn/PayloadDataEntity.java b/examples_java/src/persist/txn/PayloadDataEntity.java new file mode 100644 index 0000000..9d464ff --- /dev/null +++ b/examples_java/src/persist/txn/PayloadDataEntity.java @@ -0,0 +1,33 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 2008-2009 Oracle. All rights reserved. + * + * $Id$ + */ + +package persist.txn; + +import com.sleepycat.persist.model.Entity; +import com.sleepycat.persist.model.PrimaryKey; +import static com.sleepycat.persist.model.Relationship.*; + +@Entity +public class PayloadDataEntity { + @PrimaryKey + private int oID; + + private String threadName; + + private double doubleData; + + PayloadDataEntity() {} + + public double getDoubleData() { return doubleData; } + public int getID() { return oID; } + public String getThreadName() { return threadName; } + + public void setDoubleData(double dd) { doubleData = dd; } + public void setID(int id) { oID = id; } + public void setThreadName(String tn) { threadName = tn; } +} diff --git a/examples_java/src/persist/txn/StoreWriter.java b/examples_java/src/persist/txn/StoreWriter.java new file mode 100644 index 0000000..fb8b4e5 --- /dev/null +++ b/examples_java/src/persist/txn/StoreWriter.java @@ -0,0 +1,176 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 2008-2009 Oracle. All rights reserved. + * + * $Id$ + */ + +package persist.txn; + +import com.sleepycat.db.CursorConfig; +import com.sleepycat.db.DatabaseException; +import com.sleepycat.db.DeadlockException; +import com.sleepycat.db.Environment; +import com.sleepycat.db.Transaction; + +import com.sleepycat.persist.EntityCursor; +import com.sleepycat.persist.EntityStore; +import com.sleepycat.persist.PrimaryIndex; + +import java.util.Iterator; +import java.util.Random; +import java.io.UnsupportedEncodingException; + +public class StoreWriter extends Thread +{ + private EntityStore myStore = null; + private Environment myEnv = null; + private PrimaryIndex<Integer,PayloadDataEntity> pdKey; + private Random generator = new Random(); + private boolean passTxn = false; + + + private static final int MAX_RETRY = 20; + + // Constructor. Get our handles from here + StoreWriter(Environment env, EntityStore store) + + throws DatabaseException { + myStore = store; + myEnv = env; + + // Open the data accessor. This is used to store persistent + // objects. + pdKey = myStore.getPrimaryIndex(Integer.class, + PayloadDataEntity.class); + } + + // Thread method that writes a series of objects + // to the store using transaction protection. + // Deadlock handling is demonstrated here. + public void run () { + Transaction txn = null; + + // Perform 50 transactions + for (int i=0; i<50; i++) { + + boolean retry = true; + int retry_count = 0; + // while loop is used for deadlock retries + while (retry) { + // try block used for deadlock detection and + // general exception handling + try { + + // Get a transaction + txn = myEnv.beginTransaction(null, null); + + // Write 10 PayloadDataEntity objects to the + // store for each transaction + for (int j = 0; j < 10; j++) { + // Instantiate an object + PayloadDataEntity pd = new PayloadDataEntity(); + + // Set the Object ID. This is used as the primary key. + pd.setID(i + j); + + // The thread name is used as a secondary key, and + // it is retrieved by this class's getName() method. + pd.setThreadName(getName()); + + // The last bit of data that we use is a double + // that we generate randomly. This data is not + // indexed. + pd.setDoubleData(generator.nextDouble()); + + // Do the put + pdKey.put(txn, pd); + } + + // commit + System.out.println(getName() + " : committing txn : " + i); + System.out.println(getName() + " : Found " + + countObjects(txn) + " objects in the store."); + try { + txn.commit(); + txn = null; + } catch (DatabaseException e) { + System.err.println("Error on txn commit: " + + e.toString()); + } + retry = false; + + } catch (DeadlockException de) { + System.out.println("################# " + getName() + + " : caught deadlock"); + // retry if necessary + if (retry_count < MAX_RETRY) { + System.err.println(getName() + + " : Retrying operation."); + retry = true; + retry_count++; + } else { + System.err.println(getName() + + " : out of retries. Giving up."); + retry = false; + } + } catch (DatabaseException e) { + // abort and don't retry + retry = false; + System.err.println(getName() + + " : caught exception: " + e.toString()); + System.err.println(getName() + + " : errno: " + e.getErrno()); + e.printStackTrace(); + } finally { + if (txn != null) { + try { + txn.abort(); + } catch (Exception e) { + System.err.println("Error aborting transaction: " + + e.toString()); + e.printStackTrace(); + } + } + } + } + } + } + + // This simply counts the number of objects contained in the + // store and returns the result. You can use this method + // in three ways: + // + // First call it with an active txn handle. + // + // Secondly, configure the cursor for dirty reads + // + // Third, call countObjects AFTER the writer has committed + // its transaction. + // + // If you do none of these things, the writer thread will + // self-deadlock. + private int countObjects(Transaction txn) throws DatabaseException { + int count = 0; + + CursorConfig cc = new CursorConfig(); + // This is ignored if the store is not opened with uncommitted read + // support. + cc.setReadUncommitted(true); + EntityCursor<PayloadDataEntity> cursor = pdKey.entities(txn, cc); + + try { + for (PayloadDataEntity pdi : cursor) { + count++; + } + } finally { + if (cursor != null) { + cursor.close(); + } + } + + return count; + + } +} diff --git a/examples_java/src/persist/txn/TxnGuideDPL.java b/examples_java/src/persist/txn/TxnGuideDPL.java new file mode 100644 index 0000000..d429507 --- /dev/null +++ b/examples_java/src/persist/txn/TxnGuideDPL.java @@ -0,0 +1,162 @@ +/*- + * See the file LICENSE for redistribution information. + * + * Copyright (c) 2008-2009 Oracle. All rights reserved. + * + * $Id$ + */ + +// File TxnGuideDPL.java + +package persist.txn; + +import com.sleepycat.db.DatabaseConfig; +import com.sleepycat.db.DatabaseException; +import com.sleepycat.db.DatabaseType; +import com.sleepycat.db.LockDetectMode; + +import com.sleepycat.db.Environment; +import com.sleepycat.db.EnvironmentConfig; + +import com.sleepycat.persist.EntityStore; +import com.sleepycat.persist.StoreConfig; + +import java.io.File; +import java.io.FileNotFoundException; + +public class TxnGuideDPL { + + private static String myEnvPath = "./"; + private static String storeName = "exampleStore"; + + // Handles + private static EntityStore myStore = null; + private static Environment myEnv = null; + + private static final int NUMTHREADS = 5; + + private static void usage() { + System.out.println("TxnGuideDPL [-h <env directory>]"); + System.exit(-1); + } + + public static void main(String args[]) { + try { + // Parse the arguments list + parseArgs(args); + // Open the environment and store + openEnv(); + + // Start the threads + StoreWriter[] threadArray; + threadArray = new StoreWriter[NUMTHREADS]; + for (int i = 0; i < NUMTHREADS; i++) { + threadArray[i] = new StoreWriter(myEnv, myStore); + threadArray[i].start(); + } + + for (int i = 0; i < NUMTHREADS; i++) { + threadArray[i].join(); + } + } catch (Exception e) { + System.err.println("TxnGuideDPL: " + e.toString()); + e.printStackTrace(); + } finally { + closeEnv(); + } + System.out.println("All done."); + } + + + private static void openEnv() throws DatabaseException { + System.out.println("opening env and store"); + + // Set up the environment. + EnvironmentConfig myEnvConfig = new EnvironmentConfig(); + myEnvConfig.setAllowCreate(true); + myEnvConfig.setInitializeCache(true); + myEnvConfig.setInitializeLocking(true); + myEnvConfig.setInitializeLogging(true); + myEnvConfig.setRunRecovery(true); + myEnvConfig.setTransactional(true); + // EnvironmentConfig.setThreaded(true) is the default behavior + // in Java, so we do not have to do anything to cause the + // environment handle to be free-threaded. + + // Indicate that we want db to internally perform deadlock + // detection. Also indicate that the transaction that has + // performed the least amount of write activity to + // receive the deadlock notification, if any. + myEnvConfig.setLockDetectMode(LockDetectMode.MINWRITE); + + // Set up the entity store + StoreConfig myStoreConfig = new StoreConfig(); + myStoreConfig.setAllowCreate(true); + myStoreConfig.setTransactional(true); + + // Need a DatabaseConfig object so as to set uncommitted read + // support. + DatabaseConfig myDbConfig = new DatabaseConfig(); + myDbConfig.setType(DatabaseType.BTREE); + myDbConfig.setAllowCreate(true); + myDbConfig.setTransactional(true); + myDbConfig.setReadUncommitted(true); + + try { + // Open the environment + myEnv = new Environment(new File(myEnvPath), // Env home + myEnvConfig); + + // Open the store + myStore = new EntityStore(myEnv, storeName, myStoreConfig); + + // Set the DatabaseConfig object, so that the underlying + // database is configured for uncommitted reads. + myStore.setPrimaryConfig(PayloadDataEntity.class, myDbConfig); + } catch (FileNotFoundException fnfe) { + System.err.println("openEnv: " + fnfe.toString()); + System.exit(-1); + } + } + + private static void closeEnv() { + System.out.println("Closing env and store"); + if (myStore != null ) { + try { + myStore.close(); + } catch (DatabaseException e) { + System.err.println("closeEnv: myStore: " + + e.toString()); + e.printStackTrace(); + } + } + + if (myEnv != null ) { + try { + myEnv.close(); + } catch (DatabaseException e) { + System.err.println("closeEnv: " + e.toString()); + e.printStackTrace(); + } + } + } + + private TxnGuideDPL() {} + + private static void parseArgs(String args[]) { + int nArgs = args.length; + for(int i = 0; i < args.length; ++i) { + if (args[i].startsWith("-")) { + switch(args[i].charAt(1)) { + case 'h': + if (i < nArgs - 1) { + myEnvPath = new String(args[++i]); + } + break; + default: + usage(); + } + } + } + } +} |