FAQ
Author: xuefu
Date: Wed Dec 24 22:39:47 2014
New Revision: 1647855

URL: http://svn.apache.org/r1647855
Log:
HIVE-9199: Excessive exclusive lock used in some DDLs with DummyTxnManager (Chaoyu via Xuefu, reviewed by Alan)

Modified:
     hive/trunk/ql/src/java/org/apache/hadoop/hive/ql/lockmgr/DummyTxnManager.java

Modified: hive/trunk/ql/src/java/org/apache/hadoop/hive/ql/lockmgr/DummyTxnManager.java
URL: http://svn.apache.org/viewvc/hive/trunk/ql/src/java/org/apache/hadoop/hive/ql/lockmgr/DummyTxnManager.java?rev=1647855&r1=1647854&r2=1647855&view=diff
==============================================================================
--- hive/trunk/ql/src/java/org/apache/hadoop/hive/ql/lockmgr/DummyTxnManager.java (original)
+++ hive/trunk/ql/src/java/org/apache/hadoop/hive/ql/lockmgr/DummyTxnManager.java Wed Dec 24 22:39:47 2014
@@ -110,6 +110,9 @@ class DummyTxnManager extends HiveTxnMan
      // If a lock needs to be acquired on any partition, a read lock needs to be acquired on all
      // its parents also
      for (ReadEntity input : plan.getInputs()) {
+ if (!input.needsLock()) {
+ continue;
+ }
        LOG.debug("Adding " + input.getName() + " to list of lock inputs");
        if (input.getType() == ReadEntity.Type.DATABASE) {
          lockObjects.addAll(getLockObjects(plan, input.getDatabase(), null,
@@ -125,18 +128,18 @@ class DummyTxnManager extends HiveTxnMan
      }

      for (WriteEntity output : plan.getOutputs()) {
+ HiveLockMode lockMode = getWriteEntityLockMode(output);
+ if (lockMode == null) {
+ continue;
+ }
        LOG.debug("Adding " + output.getName() + " to list of lock outputs");
        List<HiveLockObj> lockObj = null;
        if (output.getType() == WriteEntity.Type.DATABASE) {
- lockObjects.addAll(getLockObjects(plan, output.getDatabase(), null,
- null,
- output.isComplete() ? HiveLockMode.EXCLUSIVE : HiveLockMode.SHARED));
+ lockObjects.addAll(getLockObjects(plan, output.getDatabase(), null, null, lockMode));
        } else if (output.getTyp() == WriteEntity.Type.TABLE) {
- lockObj = getLockObjects(plan, null, output.getTable(), null,
- output.isComplete() ? HiveLockMode.EXCLUSIVE : HiveLockMode.SHARED);
+ lockObj = getLockObjects(plan, null, output.getTable(), null,lockMode);
        } else if (output.getTyp() == WriteEntity.Type.PARTITION) {
- lockObj = getLockObjects(plan, null, null, output.getPartition(),
- HiveLockMode.EXCLUSIVE);
+ lockObj = getLockObjects(plan, null, null, output.getPartition(), lockMode);
        }
        // In case of dynamic queries, it is possible to have incomplete dummy partitions
        else if (output.getTyp() == WriteEntity.Type.DUMMYPARTITION) {
@@ -249,6 +252,22 @@ class DummyTxnManager extends HiveTxnMan
      }
    }

+ private HiveLockMode getWriteEntityLockMode (WriteEntity we) {
+ HiveLockMode lockMode = we.isComplete() ? HiveLockMode.EXCLUSIVE : HiveLockMode.SHARED;
+ //but the writeEntity is complete in DDL operations, and we need check its writeType to
+ //to determine the lockMode
+ switch (we.getWriteType()) {
+ case DDL_EXCLUSIVE:
+ return HiveLockMode.EXCLUSIVE;
+ case DDL_SHARED:
+ return HiveLockMode.SHARED;
+ case DDL_NO_LOCK:
+ return null;
+ default: //other writeTypes related to DMLs
+ return lockMode;
+ }
+ }
+
    private List<HiveLockObj> getLockObjects(QueryPlan plan, Database db,
                                             Table t, Partition p,
                                             HiveLockMode mode)

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groupcommits @
categorieshive, hadoop
postedDec 24, '14 at 10:39p
activeDec 24, '14 at 10:39p
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