IMPALA-8148: Misc. FE code cleanup

Roll-up of a bunch of minor code cleanup and refactoring. Pulled out of
other patches to keep those patches focused on a single change.

Tests: Reran all FE tests to verify no regressions.

Change-Id: I4e2f2e79f36e804fd592b6fe77f0554c5ca803eb
Reviewed-on: http://gerrit.cloudera.org:8080/12317
Reviewed-by: Impala Public Jenkins <[email protected]>
Tested-by: Impala Public Jenkins <[email protected]>

Author: Paul Rogers

fe/src/main/java/org/apache/impala/analysis/Analyzer.java

@@ -1755,6 +1755,7 @@ public void createEquivConjuncts(List<TupleId> lhsTids,
    * among slots in ignoreSlots are assumed to have already been enforced.
    * TODO: Consider optimizing for the cheapest minimum set of predicates.
    */
+  @SuppressWarnings("unchecked")
   public <T extends Expr> void createEquivConjuncts(TupleId tid, List<T> conjuncts,
       Set<SlotId> ignoreSlots) {
     // Maps from a slot id to its set of equivalent slots. Used to track equivalences
@@ -1929,7 +1930,7 @@ public TupleId getTupleId(SlotId slotId) {
   }
 
   public void registerValueTransfer(SlotId id1, SlotId id2) {
-    globalState_.registeredValueTransfers.add(new Pair(id1, id2));
+    globalState_.registeredValueTransfers.add(new Pair<SlotId, SlotId>(id1, id2));
   }
 
   public boolean isOuterJoined(TupleId tid) {

fe/src/main/java/org/apache/impala/analysis/CastExpr.java

@@ -29,6 +29,7 @@
 import org.apache.impala.thrift.TExpr;
 import org.apache.impala.thrift.TExprNode;
 import org.apache.impala.thrift.TExprNodeType;
+
 import com.google.common.base.Objects;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Lists;
@@ -309,6 +310,11 @@ public Expr ignoreImplicitCast() {
     }
   }
 
+  @Override
+  public boolean isImplicitCast() {
+    return isImplicit();
+  }
+
   @Override
   public boolean localEquals(Expr that) {
     if (!super.localEquals(that)) return false;

fe/src/main/java/org/apache/impala/analysis/ColumnDef.java

@@ -257,8 +257,8 @@ private void analyzeKuduOptions(Analyzer analyzer) throws AnalysisException {
         throw new AnalysisException(String.format("Only constant values are allowed " +
             "for default values: %s", defaultValue_.toSql()));
       }
-      if (defaultValLiteral.getType().isNull() && ((isNullable_ != null && !isNullable_)
-          || isPrimaryKey_)) {
+      if (Expr.IS_NULL_VALUE.apply(defaultValLiteral) &&
+          ((isNullable_ != null && !isNullable_) || isPrimaryKey_)) {
         throw new AnalysisException(String.format("Default value of NULL not allowed " +
             "on non-nullable column: '%s'", getColName()));
       }

fe/src/main/java/org/apache/impala/analysis/ComputeStatsStmt.java

@@ -131,6 +131,13 @@ public class ComputeStatsStmt extends StatementBase {
   private static final String STATS_FETCH_NUM_PARTITIONS_WITH_STATS =
       STATS_FETCH_PREFIX + ".NumPartitionsWithStats";
 
+  // The maximum number of partitions that may be explicitly selected by filter
+  // predicates. Any query that selects more than this automatically drops back to a full
+  // incremental stats recomputation.
+  // TODO: We can probably do better than this, e.g. running several queries, each of
+  // which selects up to MAX_INCREMENTAL_PARTITIONS partitions.
+  private static final int MAX_INCREMENTAL_PARTITIONS = 1000;
+
   protected final TableName tableName_;
   protected final TableSampleClause sampleParams_;
 
@@ -151,14 +158,14 @@ public class ComputeStatsStmt extends StatementBase {
   protected String columnStatsQueryStr_;
 
   // If true, stats will be gathered incrementally per-partition.
-  private boolean isIncremental_ = false;
+  private boolean isIncremental_;
 
   // If true, expect the compute stats process to produce output for all partitions in the
   // target table. In that case, 'expectedPartitions_' will be empty. The point of this
   // flag is to optimize the case where all partitions are targeted.
   // False for unpartitioned HDFS tables, non-HDFS tables or when stats extrapolation
   // is enabled.
-  private boolean expectAllPartitions_ = false;
+  private boolean expectAllPartitions_;
 
   // The list of valid partition statistics that can be used in an incremental computation
   // without themselves being recomputed. Populated in analyze().
@@ -173,23 +180,16 @@ public class ComputeStatsStmt extends StatementBase {
 
   // If non-null, partitions that an incremental computation might apply to. Must be
   // null if this is a non-incremental computation.
-  private PartitionSet partitionSet_ = null;
+  private PartitionSet partitionSet_;
 
   // If non-null, represents the user-specified list of columns for computing statistics.
   // Not supported for incremental statistics.
-  private List<String> columnWhitelist_ = null;
+  private List<String> columnWhitelist_;
 
   // The set of columns to be analyzed. Each column is valid: it must exist in the table
   // schema, it must be of a type that can be analyzed, and cannot refer to a partitioning
   // column for HDFS tables. If the set is null, no columns are restricted.
-  private Set<Column> validatedColumnWhitelist_ = null;
-
-  // The maximum number of partitions that may be explicitly selected by filter
-  // predicates. Any query that selects more than this automatically drops back to a full
-  // incremental stats recomputation.
-  // TODO: We can probably do better than this, e.g. running several queries, each of
-  // which selects up to MAX_INCREMENTAL_PARTITIONS partitions.
-  private static final int MAX_INCREMENTAL_PARTITIONS = 1000;
+  private Set<Column> validatedColumnWhitelist_;
 
   /**
    * Should only be constructed via static creation functions.