Examples with HiveTxnManager org.apache.hadoop.hive.ql.lockmgr.HiveTxnManager used on opensource projects

Example 11 with HiveTxnManager

use of org.apache.hadoop.hive.ql.lockmgr.HiveTxnManager in project hive by apache.

the class Driver method acquireLocksAndOpenTxn.

/**
   * Acquire read and write locks needed by the statement. The list of objects to be locked are
   * obtained from the inputs and outputs populated by the compiler. The lock acquisition scheme is
   * pretty simple. If all the locks cannot be obtained, error out. Deadlock is avoided by making
   * sure that the locks are lexicographically sorted.
   *
   * This method also records the list of valid transactions.  This must be done after any
   * transactions have been opened and locks acquired.
   * @param startTxnImplicitly in AC=false, the 1st DML starts a txn
   **/
private int acquireLocksAndOpenTxn(boolean startTxnImplicitly) {
    PerfLogger perfLogger = SessionState.getPerfLogger();
    perfLogger.PerfLogBegin(CLASS_NAME, PerfLogger.ACQUIRE_READ_WRITE_LOCKS);
    SessionState ss = SessionState.get();
    HiveTxnManager txnMgr = ss.getTxnMgr();
    if (startTxnImplicitly) {
        assert !txnMgr.getAutoCommit();
    }
    try {
        // Don't use the userName member, as it may or may not have been set.  Get the value from
        // conf, which calls into getUGI to figure out who the process is running as.
        String userFromUGI;
        try {
            userFromUGI = conf.getUser();
        } catch (IOException e) {
            errorMessage = "FAILED: Error in determining user while acquiring locks: " + e.getMessage();
            SQLState = ErrorMsg.findSQLState(e.getMessage());
            downstreamError = e;
            console.printError(errorMessage, "\n" + org.apache.hadoop.util.StringUtils.stringifyException(e));
            return 10;
        }
        boolean initiatingTransaction = false;
        boolean readOnlyQueryInAutoCommit = false;
        if ((txnMgr.getAutoCommit() && haveAcidWrite()) || plan.getOperation() == HiveOperation.START_TRANSACTION || (!txnMgr.getAutoCommit() && startTxnImplicitly)) {
            if (txnMgr.isTxnOpen()) {
                throw new RuntimeException("Already have an open transaction txnid:" + txnMgr.getCurrentTxnId());
            }
            // We are writing to tables in an ACID compliant way, so we need to open a transaction
            txnMgr.openTxn(ctx, userFromUGI);
            initiatingTransaction = true;
        } else {
            readOnlyQueryInAutoCommit = txnMgr.getAutoCommit() && plan.getOperation() == HiveOperation.QUERY && !haveAcidWrite();
        }
        // Set the transaction id in all of the acid file sinks
        if (haveAcidWrite()) {
            for (FileSinkDesc desc : acidSinks) {
                desc.setTransactionId(txnMgr.getCurrentTxnId());
                //it's possible to have > 1 FileSink writing to the same table/partition
                //e.g. Merge stmt, multi-insert stmt when mixing DP and SP writes
                desc.setStatementId(txnMgr.getWriteIdAndIncrement());
            }
        }
        /*Note, we have to record snapshot after lock acquisition to prevent lost update problem
      consider 2 concurrent "update table T set x = x + 1".  1st will get the locks and the
      2nd will block until 1st one commits and only then lock in the snapshot, i.e. it will
      see the changes made by 1st one.  This takes care of autoCommit=true case.
      For multi-stmt txns this is not sufficient and will be managed via WriteSet tracking
      in the lock manager.*/
        txnMgr.acquireLocks(plan, ctx, userFromUGI, lDrvState);
        if (initiatingTransaction || (readOnlyQueryInAutoCommit && acidInQuery)) {
            //For multi-stmt txns we should record the snapshot when txn starts but
            // don't update it after that until txn completes.  Thus the check for {@code initiatingTransaction}
            //For autoCommit=true, Read-only statements, txn is implicit, i.e. lock in the snapshot
            //for each statement.
            recordValidTxns();
        }
        return 0;
    } catch (Exception e) {
        errorMessage = "FAILED: Error in acquiring locks: " + e.getMessage();
        SQLState = ErrorMsg.findSQLState(e.getMessage());
        downstreamError = e;
        console.printError(errorMessage, "\n" + org.apache.hadoop.util.StringUtils.stringifyException(e));
        return 10;
    } finally {
        perfLogger.PerfLogEnd(CLASS_NAME, PerfLogger.ACQUIRE_READ_WRITE_LOCKS);
    }
}

Example 12 with HiveTxnManager

use of org.apache.hadoop.hive.ql.lockmgr.HiveTxnManager in project hive by apache.

the class Driver method recordValidTxns.

// Write the current set of valid transactions into the conf file so that it can be read by
// the input format.
private void recordValidTxns() throws LockException {
    HiveTxnManager txnMgr = SessionState.get().getTxnMgr();
    ValidTxnList txns = txnMgr.getValidTxns();
    String txnStr = txns.toString();
    conf.set(ValidTxnList.VALID_TXNS_KEY, txnStr);
    if (plan.getFetchTask() != null) {
        /**
       * This is needed for {@link HiveConf.ConfVars.HIVEFETCHTASKCONVERSION} optimization which
       * initializes JobConf in FetchOperator before recordValidTxns() but this has to be done
       * after locks are acquired to avoid race conditions in ACID.
       */
        plan.getFetchTask().setValidTxnList(txnStr);
    }
    LOG.debug("Encoding valid txns info " + txnStr + " txnid:" + txnMgr.getCurrentTxnId());
}

Example 13 with HiveTxnManager

use of org.apache.hadoop.hive.ql.lockmgr.HiveTxnManager in project hive by apache.

the class DDLTask method unlockTable.

/**
   * Unlock the table/partition specified
   * @param db
   *
   * @param unlockTbl
   *          the table/partition to be unlocked
   * @return Returns 0 when execution succeeds and above 0 if it fails.
   * @throws HiveException
   *           Throws this exception if an unexpected error occurs.
   */
private int unlockTable(Hive db, UnlockTableDesc unlockTbl) throws HiveException {
    Context ctx = driverContext.getCtx();
    HiveTxnManager txnManager = ctx.getHiveTxnManager();
    return txnManager.unlockTable(db, unlockTbl);
}