remove extra materialized view locking

Author: kasakrisz

ql/src/java/org/apache/hadoop/hive/ql/ddl/view/materialized/alter/rebuild/AlterMaterializedViewRebuildAnalyzer.java

@@ -205,23 +205,6 @@ private ASTNode getRewrittenAST(TableName tableName) throws SemanticException {
           tableName.getEscapedNotEmptyDbTable(), viewText);
       rewrittenAST = ParseUtils.parse(rewrittenInsertStatement, ctx);
       this.ctx.addSubContext(ctx);
-
-      if (!this.ctx.isExplainPlan() && (AcidUtils.isTransactionalTable(table))) {
-        // Acquire lock for the given materialized view. Only one rebuild per materialized view can be triggered at a
-        // given time, as otherwise we might produce incorrect results if incremental maintenance is triggered.
-        HiveTxnManager txnManager = getTxnMgr();
-        LockState state;
-        try {
-          state = txnManager.acquireMaterializationRebuildLock(
-              tableName.getDb(), tableName.getTable(), txnManager.getCurrentTxnId()).getState();
-        } catch (LockException e) {
-          throw new SemanticException("Exception acquiring lock for rebuilding the materialized view", e);
-        }
-        if (state != LockState.ACQUIRED) {
-          throw new SemanticException(
-              "Another process is rebuilding the materialized view " + tableName.getNotEmptyDbTable());
-        }
-      }
     } catch (Exception e) {
       throw new SemanticException(e);
     }