List of usage examples for java.sql Connection TRANSACTION_READ_COMMITTED
int TRANSACTION_READ_COMMITTED
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From source file:org.apache.hadoop.hive.metastore.txn.TxnHandler.java
/** * Concurrency/isolation notes:// w ww.ja va 2s . c om * This is mutexed with {@link #openTxns(OpenTxnRequest)} and other {@link #commitTxn(CommitTxnRequest)} * operations using select4update on NEXT_TXN_ID. Also, mutexes on TXNX table for specific txnid:X * see more notes below. * In order to prevent lost updates, we need to determine if any 2 transactions overlap. Each txn * is viewed as an interval [M,N]. M is the txnid and N is taken from the same NEXT_TXN_ID sequence * so that we can compare commit time of txn T with start time of txn S. This sequence can be thought of * as a logical time counter. If S.commitTime < T.startTime, T and S do NOT overlap. * * Motivating example: * Suppose we have multi-statment transactions T and S both of which are attempting x = x + 1 * In order to prevent lost update problem, the the non-overlapping txns must lock in the snapshot * that they read appropriately. In particular, if txns do not overlap, then one follows the other * (assumig they write the same entity), and thus the 2nd must see changes of the 1st. We ensure * this by locking in snapshot after * {@link #openTxns(OpenTxnRequest)} call is made (see {@link org.apache.hadoop.hive.ql.Driver#acquireLocksAndOpenTxn()}) * and mutexing openTxn() with commit(). In other words, once a S.commit() starts we must ensure * that txn T which will be considered a later txn, locks in a snapshot that includes the result * of S's commit (assuming no other txns). * As a counter example, suppose we have S[3,3] and T[4,4] (commitId=txnid means no other transactions * were running in parallel). If T and S both locked in the same snapshot (for example commit of * txnid:2, which is possible if commitTxn() and openTxnx() is not mutexed) * 'x' would be updated to the same value by both, i.e. lost update. */ @Override @RetrySemantics.Idempotent("No-op if already committed") public void commitTxn(CommitTxnRequest rqst) throws NoSuchTxnException, TxnAbortedException, MetaException { long txnid = rqst.getTxnid(); try { Connection dbConn = null; Statement stmt = null; ResultSet lockHandle = null; ResultSet commitIdRs = null, rs; try { lockInternal(); dbConn = getDbConn(Connection.TRANSACTION_READ_COMMITTED); stmt = dbConn.createStatement(); /** * Runs at READ_COMMITTED with S4U on TXNS row for "txnid". S4U ensures that no other * operation can change this txn (such acquiring locks). While lock() and commitTxn() * should not normally run concurrently (for same txn) but could due to bugs in the client * which could then corrupt internal transaction manager state. Also competes with abortTxn(). */ lockHandle = lockTransactionRecord(stmt, txnid, TXN_OPEN); if (lockHandle == null) { //if here, txn was not found (in expected state) TxnStatus actualTxnStatus = findTxnState(txnid, stmt); if (actualTxnStatus == TxnStatus.COMMITTED) { /** * This makes the operation idempotent * (assume that this is most likely due to retry logic) */ LOG.info("Nth commitTxn(" + JavaUtils.txnIdToString(txnid) + ") msg"); return; } raiseTxnUnexpectedState(actualTxnStatus, txnid); shouldNeverHappen(txnid); //dbConn is rolled back in finally{} } String conflictSQLSuffix = "from TXN_COMPONENTS where tc_txnid=" + txnid + " and tc_operation_type IN(" + quoteChar(OpertaionType.UPDATE.sqlConst) + "," + quoteChar(OpertaionType.DELETE.sqlConst) + ")"; rs = stmt.executeQuery(sqlGenerator.addLimitClause(1, "tc_operation_type " + conflictSQLSuffix)); if (rs.next()) { close(rs); //if here it means currently committing txn performed update/delete and we should check WW conflict /** * This S4U will mutex with other commitTxn() and openTxns(). * -1 below makes txn intervals look like [3,3] [4,4] if all txns are serial * Note: it's possible to have several txns have the same commit id. Suppose 3 txns start * at the same time and no new txns start until all 3 commit. * We could've incremented the sequence for commitId is well but it doesn't add anything functionally. */ commitIdRs = stmt .executeQuery(sqlGenerator.addForUpdateClause("select ntxn_next - 1 from NEXT_TXN_ID")); if (!commitIdRs.next()) { throw new IllegalStateException("No rows found in NEXT_TXN_ID"); } long commitId = commitIdRs.getLong(1); Savepoint undoWriteSetForCurrentTxn = dbConn.setSavepoint(); /** * "select distinct" is used below because * 1. once we get to multi-statement txns, we only care to record that something was updated once * 2. if {@link #addDynamicPartitions(AddDynamicPartitions)} is retried by caller it my create * duplicate entries in TXN_COMPONENTS * but we want to add a PK on WRITE_SET which won't have unique rows w/o this distinct * even if it includes all of it's columns */ int numCompsWritten = stmt.executeUpdate( "insert into WRITE_SET (ws_database, ws_table, ws_partition, ws_txnid, ws_commit_id, ws_operation_type)" + " select distinct tc_database, tc_table, tc_partition, tc_txnid, " + commitId + ", tc_operation_type " + conflictSQLSuffix); /** * see if there are any overlapping txns wrote the same element, i.e. have a conflict * Since entire commit operation is mutexed wrt other start/commit ops, * committed.ws_commit_id <= current.ws_commit_id for all txns * thus if committed.ws_commit_id < current.ws_txnid, transactions do NOT overlap * For example, [17,20] is committed, [6,80] is being committed right now - these overlap * [17,20] committed and [21,21] committing now - these do not overlap. * [17,18] committed and [18,19] committing now - these overlap (here 18 started while 17 was still running) */ rs = stmt.executeQuery(sqlGenerator.addLimitClause(1, "committed.ws_txnid, committed.ws_commit_id, committed.ws_database," + "committed.ws_table, committed.ws_partition, cur.ws_commit_id cur_ws_commit_id, " + "cur.ws_operation_type cur_op, committed.ws_operation_type committed_op " + "from WRITE_SET committed INNER JOIN WRITE_SET cur " + "ON committed.ws_database=cur.ws_database and committed.ws_table=cur.ws_table " + //For partitioned table we always track writes at partition level (never at table) //and for non partitioned - always at table level, thus the same table should never //have entries with partition key and w/o "and (committed.ws_partition=cur.ws_partition or (committed.ws_partition is null and cur.ws_partition is null)) " + "where cur.ws_txnid <= committed.ws_commit_id" + //txns overlap; could replace ws_txnid // with txnid, though any decent DB should infer this " and cur.ws_txnid=" + txnid + //make sure RHS of join only has rows we just inserted as // part of this commitTxn() op " and committed.ws_txnid <> " + txnid + //and LHS only has committed txns //U+U and U+D is a conflict but D+D is not and we don't currently track I in WRITE_SET at all " and (committed.ws_operation_type=" + quoteChar(OpertaionType.UPDATE.sqlConst) + " OR cur.ws_operation_type=" + quoteChar(OpertaionType.UPDATE.sqlConst) + ")")); if (rs.next()) { //found a conflict String committedTxn = "[" + JavaUtils.txnIdToString(rs.getLong(1)) + "," + rs.getLong(2) + "]"; StringBuilder resource = new StringBuilder(rs.getString(3)).append("/") .append(rs.getString(4)); String partitionName = rs.getString(5); if (partitionName != null) { resource.append('/').append(partitionName); } String msg = "Aborting [" + JavaUtils.txnIdToString(txnid) + "," + rs.getLong(6) + "]" + " due to a write conflict on " + resource + " committed by " + committedTxn + " " + rs.getString(7) + "/" + rs.getString(8); close(rs); //remove WRITE_SET info for current txn since it's about to abort dbConn.rollback(undoWriteSetForCurrentTxn); LOG.info(msg); //todo: should make abortTxns() write something into TXNS.TXN_META_INFO about this if (abortTxns(dbConn, Collections.singletonList(txnid), true) != 1) { throw new IllegalStateException(msg + " FAILED!"); } dbConn.commit(); close(null, stmt, dbConn); throw new TxnAbortedException(msg); } else { //no conflicting operations, proceed with the rest of commit sequence } } else { /** * current txn didn't update/delete anything (may have inserted), so just proceed with commit * * We only care about commit id for write txns, so for RO (when supported) txns we don't * have to mutex on NEXT_TXN_ID. * Consider: if RO txn is after a W txn, then RO's openTxns() will be mutexed with W's * commitTxn() because both do S4U on NEXT_TXN_ID and thus RO will see result of W txn. * If RO < W, then there is no reads-from relationship. */ } // Move the record from txn_components into completed_txn_components so that the compactor // knows where to look to compact. String s = "insert into COMPLETED_TXN_COMPONENTS select tc_txnid, tc_database, tc_table, " + "tc_partition from TXN_COMPONENTS where tc_txnid = " + txnid; LOG.debug("Going to execute insert <" + s + ">"); int modCount = 0; if ((modCount = stmt.executeUpdate(s)) < 1) { //this can be reasonable for an empty txn START/COMMIT or read-only txn //also an IUD with DP that didn't match any rows. LOG.info("Expected to move at least one record from txn_components to " + "completed_txn_components when committing txn! " + JavaUtils.txnIdToString(txnid)); } s = "delete from TXN_COMPONENTS where tc_txnid = " + txnid; LOG.debug("Going to execute update <" + s + ">"); modCount = stmt.executeUpdate(s); s = "delete from HIVE_LOCKS where hl_txnid = " + txnid; LOG.debug("Going to execute update <" + s + ">"); modCount = stmt.executeUpdate(s); s = "delete from TXNS where txn_id = " + txnid; LOG.debug("Going to execute update <" + s + ">"); modCount = stmt.executeUpdate(s); LOG.debug("Going to commit"); dbConn.commit(); } catch (SQLException e) { LOG.debug("Going to rollback"); rollbackDBConn(dbConn); checkRetryable(dbConn, e, "commitTxn(" + rqst + ")"); throw new MetaException( "Unable to update transaction database " + StringUtils.stringifyException(e)); } finally { close(commitIdRs); close(lockHandle, stmt, dbConn); unlockInternal(); } } catch (RetryException e) { commitTxn(rqst); } }
From source file:massbank.DatabaseManager.java
private HashMap<String, String> getDatabaseOfAccessions() { GetConfig config = new GetConfig(MassBankEnv.get(MassBankEnv.KEY_BASE_URL)); String[] dbNames = config.getDbName(); HashMap<String, String> dbMapping = new HashMap<String, String>(); Connection con = null;//ww w .j a v a2 s . c o m try { Class.forName(driver); con = DriverManager.getConnection(connectUrl, user, password); con.setAutoCommit(false); con.setTransactionIsolation(java.sql.Connection.TRANSACTION_READ_COMMITTED); for (String db : dbNames) { String sql = "SELECT ACCESSION FROM " + db + ".RECORD"; PreparedStatement stmnt = con.prepareStatement(sql); ResultSet resultSet = stmnt.executeQuery(); while (resultSet.next()) { dbMapping.put(resultSet.getString("ACCESSION"), db); } resultSet.close(); } } catch (Exception e) { e.printStackTrace(); } finally { if (con != null) try { con.close(); } catch (SQLException e) { e.printStackTrace(); } } return dbMapping; }
From source file:com.alibaba.wasp.jdbc.result.JdbcDatabaseMetaData.java
/** * Returns the default transaction isolation level. * /* w w w .ja va 2 s . c o m*/ * @return Connection.TRANSACTION_READ_COMMITTED */ public int getDefaultTransactionIsolation() { return Connection.TRANSACTION_READ_COMMITTED; }
From source file:com.cloud.utils.db.TransactionLegacy.java
@SuppressWarnings({ "rawtypes", "unchecked" })
public static void initDataSource(Properties dbProps) {
try {/* w w w .j a va2 s.com*/
if (dbProps.size() == 0)
return;
s_dbHAEnabled = Boolean.valueOf(dbProps.getProperty("db.ha.enabled"));
s_logger.info("Is Data Base High Availiability enabled? Ans : " + s_dbHAEnabled);
String loadBalanceStrategy = dbProps.getProperty("db.ha.loadBalanceStrategy");
// FIXME: If params are missing...default them????
final int cloudMaxActive = Integer.parseInt(dbProps.getProperty("db.cloud.maxActive"));
final int cloudMaxIdle = Integer.parseInt(dbProps.getProperty("db.cloud.maxIdle"));
final long cloudMaxWait = Long.parseLong(dbProps.getProperty("db.cloud.maxWait"));
final String cloudUsername = dbProps.getProperty("db.cloud.username");
final String cloudPassword = dbProps.getProperty("db.cloud.password");
final String cloudHost = dbProps.getProperty("db.cloud.host");
final String cloudDriver = dbProps.getProperty("db.cloud.driver");
final int cloudPort = Integer.parseInt(dbProps.getProperty("db.cloud.port"));
final String cloudDbName = dbProps.getProperty("db.cloud.name");
final boolean cloudAutoReconnect = Boolean.parseBoolean(dbProps.getProperty("db.cloud.autoReconnect"));
final String cloudValidationQuery = dbProps.getProperty("db.cloud.validationQuery");
final String cloudIsolationLevel = dbProps.getProperty("db.cloud.isolation.level");
int isolationLevel = Connection.TRANSACTION_READ_COMMITTED;
if (cloudIsolationLevel == null) {
isolationLevel = Connection.TRANSACTION_READ_COMMITTED;
} else if (cloudIsolationLevel.equalsIgnoreCase("readcommitted")) {
isolationLevel = Connection.TRANSACTION_READ_COMMITTED;
} else if (cloudIsolationLevel.equalsIgnoreCase("repeatableread")) {
isolationLevel = Connection.TRANSACTION_REPEATABLE_READ;
} else if (cloudIsolationLevel.equalsIgnoreCase("serializable")) {
isolationLevel = Connection.TRANSACTION_SERIALIZABLE;
} else if (cloudIsolationLevel.equalsIgnoreCase("readuncommitted")) {
isolationLevel = Connection.TRANSACTION_READ_UNCOMMITTED;
} else {
s_logger.warn("Unknown isolation level " + cloudIsolationLevel + ". Using read uncommitted");
}
final boolean cloudTestOnBorrow = Boolean.parseBoolean(dbProps.getProperty("db.cloud.testOnBorrow"));
final boolean cloudTestWhileIdle = Boolean.parseBoolean(dbProps.getProperty("db.cloud.testWhileIdle"));
final long cloudTimeBtwEvictionRunsMillis = Long
.parseLong(dbProps.getProperty("db.cloud.timeBetweenEvictionRunsMillis"));
final long cloudMinEvcitableIdleTimeMillis = Long
.parseLong(dbProps.getProperty("db.cloud.minEvictableIdleTimeMillis"));
final boolean cloudPoolPreparedStatements = Boolean
.parseBoolean(dbProps.getProperty("db.cloud.poolPreparedStatements"));
final String url = dbProps.getProperty("db.cloud.url.params");
String cloudDbHAParams = null;
String cloudSlaves = null;
if (s_dbHAEnabled) {
cloudDbHAParams = getDBHAParams("cloud", dbProps);
cloudSlaves = dbProps.getProperty("db.cloud.slaves");
s_logger.info("The slaves configured for Cloud Data base is/are : " + cloudSlaves);
}
final boolean useSSL = Boolean.parseBoolean(dbProps.getProperty("db.cloud.useSSL"));
if (useSSL) {
System.setProperty("javax.net.ssl.keyStore", dbProps.getProperty("db.cloud.keyStore"));
System.setProperty("javax.net.ssl.keyStorePassword",
dbProps.getProperty("db.cloud.keyStorePassword"));
System.setProperty("javax.net.ssl.trustStore", dbProps.getProperty("db.cloud.trustStore"));
System.setProperty("javax.net.ssl.trustStorePassword",
dbProps.getProperty("db.cloud.trustStorePassword"));
}
final GenericObjectPool cloudConnectionPool = new GenericObjectPool(null, cloudMaxActive,
GenericObjectPool.DEFAULT_WHEN_EXHAUSTED_ACTION, cloudMaxWait, cloudMaxIdle, cloudTestOnBorrow,
false, cloudTimeBtwEvictionRunsMillis, 1, cloudMinEvcitableIdleTimeMillis, cloudTestWhileIdle);
final String cloudConnectionUri = cloudDriver + "://" + cloudHost
+ (s_dbHAEnabled ? "," + cloudSlaves : "") + ":" + cloudPort + "/" + cloudDbName
+ "?autoReconnect=" + cloudAutoReconnect + (url != null ? "&" + url : "")
+ (useSSL ? "&useSSL=true" : "") + (s_dbHAEnabled ? "&" + cloudDbHAParams : "")
+ (s_dbHAEnabled ? "&loadBalanceStrategy=" + loadBalanceStrategy : "");
DriverLoader.loadDriver(cloudDriver);
final ConnectionFactory cloudConnectionFactory = new DriverManagerConnectionFactory(cloudConnectionUri,
cloudUsername, cloudPassword);
final KeyedObjectPoolFactory poolableObjFactory = (cloudPoolPreparedStatements
? new StackKeyedObjectPoolFactory()
: null);
final PoolableConnectionFactory cloudPoolableConnectionFactory = new PoolableConnectionFactory(
cloudConnectionFactory, cloudConnectionPool, poolableObjFactory, cloudValidationQuery, false,
false, isolationLevel);
// Default Data Source for CloudStack
s_ds = new PoolingDataSource(cloudPoolableConnectionFactory.getPool());
// Configure the usage db
final int usageMaxActive = Integer.parseInt(dbProps.getProperty("db.usage.maxActive"));
final int usageMaxIdle = Integer.parseInt(dbProps.getProperty("db.usage.maxIdle"));
final long usageMaxWait = Long.parseLong(dbProps.getProperty("db.usage.maxWait"));
final String usageUsername = dbProps.getProperty("db.usage.username");
final String usagePassword = dbProps.getProperty("db.usage.password");
final String usageHost = dbProps.getProperty("db.usage.host");
final String usageDriver = dbProps.getProperty("db.usage.driver");
final int usagePort = Integer.parseInt(dbProps.getProperty("db.usage.port"));
final String usageDbName = dbProps.getProperty("db.usage.name");
final boolean usageAutoReconnect = Boolean.parseBoolean(dbProps.getProperty("db.usage.autoReconnect"));
final String usageUrl = dbProps.getProperty("db.usage.url.params");
final GenericObjectPool usageConnectionPool = new GenericObjectPool(null, usageMaxActive,
GenericObjectPool.DEFAULT_WHEN_EXHAUSTED_ACTION, usageMaxWait, usageMaxIdle);
final String usageConnectionUri = usageDriver + "://" + usageHost
+ (s_dbHAEnabled ? "," + dbProps.getProperty("db.cloud.slaves") : "") + ":" + usagePort + "/"
+ usageDbName + "?autoReconnect=" + usageAutoReconnect
+ (usageUrl != null ? "&" + usageUrl : "")
+ (s_dbHAEnabled ? "&" + getDBHAParams("usage", dbProps) : "")
+ (s_dbHAEnabled ? "&loadBalanceStrategy=" + loadBalanceStrategy : "");
DriverLoader.loadDriver(usageDriver);
final ConnectionFactory usageConnectionFactory = new DriverManagerConnectionFactory(usageConnectionUri,
usageUsername, usagePassword);
final PoolableConnectionFactory usagePoolableConnectionFactory = new PoolableConnectionFactory(
usageConnectionFactory, usageConnectionPool, new StackKeyedObjectPoolFactory(), null, false,
false);
// Data Source for usage server
s_usageDS = new PoolingDataSource(usagePoolableConnectionFactory.getPool());
try {
// Configure the simulator db
final int simulatorMaxActive = Integer.parseInt(dbProps.getProperty("db.simulator.maxActive"));
final int simulatorMaxIdle = Integer.parseInt(dbProps.getProperty("db.simulator.maxIdle"));
final long simulatorMaxWait = Long.parseLong(dbProps.getProperty("db.simulator.maxWait"));
final String simulatorUsername = dbProps.getProperty("db.simulator.username");
final String simulatorPassword = dbProps.getProperty("db.simulator.password");
final String simulatorHost = dbProps.getProperty("db.simulator.host");
final String simulatorDriver = dbProps.getProperty("db.simulator.driver");
final int simulatorPort = Integer.parseInt(dbProps.getProperty("db.simulator.port"));
final String simulatorDbName = dbProps.getProperty("db.simulator.name");
final boolean simulatorAutoReconnect = Boolean
.parseBoolean(dbProps.getProperty("db.simulator.autoReconnect"));
final GenericObjectPool simulatorConnectionPool = new GenericObjectPool(null, simulatorMaxActive,
GenericObjectPool.DEFAULT_WHEN_EXHAUSTED_ACTION, simulatorMaxWait, simulatorMaxIdle);
final String simulatorConnectionUri = simulatorDriver + "://" + simulatorHost + ":" + simulatorPort
+ "/" + simulatorDbName + "?autoReconnect=" + simulatorAutoReconnect;
DriverLoader.loadDriver(simulatorDriver);
final ConnectionFactory simulatorConnectionFactory = new DriverManagerConnectionFactory(
simulatorConnectionUri, simulatorUsername, simulatorPassword);
final PoolableConnectionFactory simulatorPoolableConnectionFactory = new PoolableConnectionFactory(
simulatorConnectionFactory, simulatorConnectionPool, new StackKeyedObjectPoolFactory(),
null, false, false);
s_simulatorDS = new PoolingDataSource(simulatorPoolableConnectionFactory.getPool());
} catch (Exception e) {
s_logger.debug("Simulator DB properties are not available. Not initializing simulator DS");
}
} catch (final Exception e) {
s_ds = getDefaultDataSource("cloud");
s_usageDS = getDefaultDataSource("cloud_usage");
s_simulatorDS = getDefaultDataSource("cloud_simulator");
s_logger.warn(
"Unable to load db configuration, using defaults with 5 connections. Falling back on assumed datasource on localhost:3306 using username:password=cloud:cloud. Please check your configuration",
e);
}
}
From source file:org.wso2.carbon.registry.core.jdbc.dao.JDBCResourceDAO.java
public String[] getChildren(CollectionImpl collection, int start, int pageLen, DataAccessManager dataAccessManager) throws RegistryException { String[] childPaths = null;// w w w . j a v a 2s.c o m if (Transaction.isStarted()) { childPaths = getChildren(collection, start, pageLen, JDBCDatabaseTransaction.getConnection()); } else { Connection conn = null; boolean transactionSucceeded = false; try { if (!(dataAccessManager instanceof JDBCDataAccessManager)) { String msg = "Failed to get children. Invalid data access manager."; log.error(msg); throw new RegistryException(msg); } conn = ((JDBCDataAccessManager) dataAccessManager).getDataSource().getConnection(); // If a managed connection already exists, use that instead of a new // connection. JDBCDatabaseTransaction.ManagedRegistryConnection temp = JDBCDatabaseTransaction .getManagedRegistryConnection(conn); if (temp != null) { conn.close(); conn = temp; } if (conn.getTransactionIsolation() != Connection.TRANSACTION_READ_COMMITTED) { conn.setTransactionIsolation(Connection.TRANSACTION_READ_COMMITTED); } conn.setAutoCommit(false); childPaths = getChildren(collection, start, pageLen, conn); transactionSucceeded = true; } catch (SQLException e) { String msg = "Failed to get the child paths " + pageLen + " child paths from " + start + " of resource " + collection.getPath() + ". " + e.getMessage(); log.error(msg, e); throw new RegistryException(msg, e); } finally { if (transactionSucceeded) { try { conn.commit(); } catch (SQLException e) { log.error("Failed to commit the database connection used in " + "getting child paths of the collection " + collection.getPath()); } } else if (conn != null) { try { conn.rollback(); } catch (SQLException e) { log.error("Failed to rollback the database connection used in " + "getting child paths of the collection " + collection.getPath()); } } if (conn != null) { try { conn.close(); } catch (SQLException e) { log.error("Failed to close the database connection used in " + "getting child paths of the collection " + collection.getPath()); } } } } return childPaths; }
From source file:org.wso2.carbon.repository.core.jdbc.dao.JDBCResourceDAO.java
public String[] getChildren(CollectionImpl collection, int start, int pageLen, DataAccessManager dataAccessManager) throws RepositoryException { String[] childPaths = null;// ww w . j a va2 s.c om if (Transaction.isStarted()) { childPaths = getChildren(collection, start, pageLen, JDBCDatabaseTransaction.getConnection()); } else { Connection conn = null; boolean transactionSucceeded = false; try { if (!(dataAccessManager instanceof JDBCDataAccessManager)) { String msg = "Failed to get children. Invalid data access manager."; log.error(msg); throw new RepositoryDBException(msg); } conn = ((JDBCDataAccessManager) dataAccessManager).getDataSource().getConnection(); // If a managed connection already exists, use that instead of a new // connection. JDBCDatabaseTransaction.ManagedRegistryConnection temp = JDBCDatabaseTransaction .getManagedRegistryConnection(conn); if (temp != null) { conn.close(); conn = temp; } if (conn.getTransactionIsolation() != Connection.TRANSACTION_READ_COMMITTED) { conn.setTransactionIsolation(Connection.TRANSACTION_READ_COMMITTED); } conn.setAutoCommit(false); childPaths = getChildren(collection, start, pageLen, conn); transactionSucceeded = true; } catch (SQLException e) { String msg = "Failed to get the child paths " + pageLen + " child paths from " + start + " of resource " + collection.getPath() + ". " + e.getMessage(); log.error(msg, e); throw new RepositoryDBException(msg, e); } finally { if (transactionSucceeded) { try { conn.commit(); } catch (SQLException e) { log.error("Failed to commit the database connection used in " + "getting child paths of the collection " + collection.getPath()); } } else if (conn != null) { try { conn.rollback(); } catch (SQLException e) { log.error("Failed to rollback the database connection used in " + "getting child paths of the collection " + collection.getPath()); } } if (conn != null) { try { conn.close(); } catch (SQLException e) { log.error("Failed to close the database connection used in " + "getting child paths of the collection " + collection.getPath()); } } } } return childPaths; }
From source file:com.nextep.designer.dbgm.services.impl.DataService.java
private Connection getRepositoryConnection() throws SQLException { final IConnection repoConn = repositoryService.getRepositoryConnection(); final Connection jdbcConn = connectionService.connect(repoConn); jdbcConn.setTransactionIsolation(Connection.TRANSACTION_READ_COMMITTED); return jdbcConn; }
From source file:org.wso2.carbon.user.core.jdbc.JDBCUserStoreManager.java
/** * @return//from ww w . j a v a2 s. co m * @throws SQLException * @throws UserStoreException */ protected Connection getDBConnection() throws SQLException, UserStoreException { Connection dbConnection = getJDBCDataSource().getConnection(); dbConnection.setAutoCommit(false); if (dbConnection.getTransactionIsolation() != Connection.TRANSACTION_READ_COMMITTED) { dbConnection.setTransactionIsolation(Connection.TRANSACTION_READ_COMMITTED); } return dbConnection; }
From source file:org.apache.hadoop.hive.metastore.txn.TxnHandler.java
@Override @RetrySemantics.SafeToRetry//from w ww . ja v a 2 s. c o m public void performWriteSetGC() { Connection dbConn = null; Statement stmt = null; ResultSet rs = null; try { dbConn = getDbConn(Connection.TRANSACTION_READ_COMMITTED); stmt = dbConn.createStatement(); rs = stmt.executeQuery("select ntxn_next - 1 from NEXT_TXN_ID"); if (!rs.next()) { throw new IllegalStateException("NEXT_TXN_ID is empty: DB is corrupted"); } long highestAllocatedTxnId = rs.getLong(1); close(rs); rs = stmt.executeQuery("select min(txn_id) from TXNS where txn_state=" + quoteChar(TXN_OPEN)); if (!rs.next()) { throw new IllegalStateException("Scalar query returned no rows?!?!!"); } long commitHighWaterMark;//all currently open txns (if any) have txnid >= than commitHighWaterMark long lowestOpenTxnId = rs.getLong(1); if (rs.wasNull()) { //if here then there are no Open txns and highestAllocatedTxnId must be //resolved (i.e. committed or aborted), either way //there are no open txns with id <= highestAllocatedTxnId //the +1 is there because "delete ..." below has < (which is correct for the case when //there is an open txn //Concurrency: even if new txn starts (or starts + commits) it is still true that //there are no currently open txns that overlap with any committed txn with //commitId <= commitHighWaterMark (as set on next line). So plain READ_COMMITTED is enough. commitHighWaterMark = highestAllocatedTxnId + 1; } else { commitHighWaterMark = lowestOpenTxnId; } int delCnt = stmt.executeUpdate("delete from WRITE_SET where ws_commit_id < " + commitHighWaterMark); LOG.info("Deleted " + delCnt + " obsolete rows from WRTIE_SET"); dbConn.commit(); } catch (SQLException ex) { LOG.warn("WriteSet GC failed due to " + getMessage(ex), ex); } finally { close(rs, stmt, dbConn); } }
From source file:org.apache.hadoop.hive.metastore.MyXid.java
@Override public Database getDatabase(String name) throws NoSuchObjectException, MetaException { Database db = null;//w w w . jav a 2 s . co m Connection con; name = name.toLowerCase(); try { con = getSegmentConnection(name); } catch (MetaStoreConnectException e1) { LOG.error("get database error, db=" + name + ", msg=" + e1.getMessage()); throw new NoSuchObjectException(e1.getMessage()); } catch (SQLException e1) { LOG.error("get database error, db=" + name + ", msg=" + e1.getMessage()); throw new MetaException(e1.getMessage()); } Statement stmt = null; try { con.setTransactionIsolation(Connection.TRANSACTION_READ_COMMITTED); stmt = con.createStatement(); String sql = "SELECT name, hdfs_schema, description, owner FROM DBS WHERE name='" + name + "'"; ResultSet dbSet = stmt.executeQuery(sql); boolean isDBFind = false; while (dbSet.next()) { isDBFind = true; db = new Database(); db.setName(dbSet.getString(1)); db.setHdfsscheme(dbSet.getString(2)); db.setDescription(dbSet.getString(3)); db.setOwner(dbSet.getString(4)); break; } dbSet.close(); if (!isDBFind) { LOG.error("get database error, db=" + name); throw new NoSuchObjectException("database " + name + " does not exist!"); } } catch (SQLException sqlex) { sqlex.printStackTrace(); throw new MetaException(sqlex.getMessage()); } finally { closeStatement(stmt); closeConnection(con); } return db; }