public void initialize()

in ql/src/java/org/apache/hadoop/hive/ql/optimizer/Optimizer.java [59:231]
135 lines of code
51 McCabe index (conditional complexity)

  public void initialize(HiveConf hiveConf) {

    boolean isTezExecEngine = HiveConf.getVar(hiveConf, HiveConf.ConfVars.HIVE_EXECUTION_ENGINE).equals("tez");
    boolean bucketMapJoinOptimizer = false;

    transformations = new ArrayList<Transform>();

    // Add the additional postprocessing transformations needed if
    // we are translating Calcite operators into Hive operators.
    transformations.add(new HiveOpConverterPostProc());

    // Add the transformation that computes the lineage information.
    if (shouldComputeLineage(hiveConf)) {
      transformations.add(Generator.fromConf(hiveConf));
    }

    // Try to transform OR predicates in Filter into simpler IN clauses first
    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_POINT_LOOKUP_OPTIMIZER) &&
            !pctx.getContext().isCboSucceeded()) {
      final int min = HiveConf.getIntVar(hiveConf,
          HiveConf.ConfVars.HIVE_POINT_LOOKUP_OPTIMIZER_MIN);
      transformations.add(new PointLookupOptimizer(min));
    }

    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_PARTITION_COLUMN_SEPARATOR)) {
        transformations.add(new PartitionColumnsSeparator());
    }

    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_PPD) &&
            !pctx.getContext().isCboSucceeded()) {
      transformations.add(new PredicateTransitivePropagate());
      if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_CONSTANT_PROPAGATION)) {
        transformations.add(new ConstantPropagate());
      }
      transformations.add(new SyntheticJoinPredicate());
      transformations.add(new PredicatePushDown());
    } else if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_PPD) &&
            pctx.getContext().isCboSucceeded()) {
      transformations.add(new SyntheticJoinPredicate());
      transformations.add(new SimplePredicatePushDown());
      transformations.add(new RedundantDynamicPruningConditionsRemoval());
    }

    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_CONSTANT_PROPAGATION) &&
        (!pctx.getContext().isCboSucceeded() || pctx.getContext().getOperation() == Context.Operation.MERGE)) {
      // We run constant propagation twice because after predicate pushdown, filter expressions
      // are combined and may become eligible for reduction (like is not null filter).
      // CBO can not handle merge statements and some constraint check can be evaluated by constant propagation
      transformations.add(new ConstantPropagate());
    }



    transformations.add(new SortedDynPartitionTimeGranularityOptimizer());

    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_PPD)) {
      transformations.add(new PartitionPruner());
      transformations.add(new PartitionConditionRemover());
      if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_LIST_BUCKETING)) {
        /* Add list bucketing pruner. */
        transformations.add(new ListBucketingPruner());
      }
      if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_CONSTANT_PROPAGATION) &&
              !pctx.getContext().isCboSucceeded()) {
        // PartitionPruner may create more folding opportunities, run ConstantPropagate again.
        transformations.add(new ConstantPropagate());
      }
    }

    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_GROUPBY) ||
        HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_MAP_GROUPBY_SORT)) {
      transformations.add(new GroupByOptimizer());
    }
    transformations.add(new ColumnPruner());
    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_COUNT_DISTINCT_OPTIMIZER)
        && (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_IN_TEST) || isTezExecEngine)) {
      transformations.add(new CountDistinctRewriteProc());
    }
    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPTIMIZE_SKEWJOIN_COMPILETIME)) {
      if (!isTezExecEngine) {
        transformations.add(new SkewJoinOptimizer());
      } else {
        LOG.warn("Skew join is currently not supported in tez! Disabling the skew join optimization.");
      }
    }
    transformations.add(new SamplePruner());

    MapJoinProcessor mapJoinProcessor = new MapJoinProcessor();
    transformations.add(mapJoinProcessor);

    if ((HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_BUCKET_MAPJOIN))
      && !isTezExecEngine) {
      transformations.add(new BucketMapJoinOptimizer());
      bucketMapJoinOptimizer = true;
    }

    // If optimize hive.optimize.bucketmapjoin.sortedmerge is set, add both
    // BucketMapJoinOptimizer and SortedMergeBucketMapJoinOptimizer
    if ((HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_SORT_MERGE_BUCKET_MAPJOIN))
        && !isTezExecEngine) {
      if (!bucketMapJoinOptimizer) {
        // No need to add BucketMapJoinOptimizer twice
        transformations.add(new BucketMapJoinOptimizer());
      }
      transformations.add(new SortedMergeBucketMapJoinOptimizer());
    }

    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPTIMIZE_BUCKETING_SORTING)) {
      transformations.add(new BucketingSortingReduceSinkOptimizer());
    }

    transformations.add(new UnionProcessor());

    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.N_WAY_JOIN_REORDER)) {
      transformations.add(new JoinReorder());
    }

    if (HiveConf.getBoolVar(hiveConf,
        HiveConf.ConfVars.TEZ_OPTIMIZE_BUCKET_PRUNING)
        && HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_PPD)
        && HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_INDEX_FILTER)) {
      final boolean compatMode =
          HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.TEZ_OPTIMIZE_BUCKET_PRUNING_COMPAT);
      transformations.add(new FixedBucketPruningOptimizer(compatMode));
    }

    transformations.add(new BucketVersionPopulator());

    if(HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_REDUCE_DEDUPLICATION) &&
        !isTezExecEngine) {
      transformations.add(new ReduceSinkDeDuplication());
    }
    transformations.add(new NonBlockingOpDeDupProc());
    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_IDENTITY_PROJECT_REMOVER)
        && !HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_CBO_RETPATH_HIVEOP)) {
      transformations.add(new IdentityProjectRemover());
    }
    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_LIMIT_OPT_ENABLE)) {
      transformations.add(new GlobalLimitOptimizer());
    }
    if(HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPT_CORRELATION) &&
        !HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_GROUPBY_SKEW) &&
        !HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPTIMIZE_SKEWJOIN_COMPILETIME) &&
        !isTezExecEngine) {
      transformations.add(new CorrelationOptimizer());
    }
    if (HiveConf.getFloatVar(hiveConf, HiveConf.ConfVars.HIVE_LIMIT_PUSHDOWN_MEMORY_USAGE) > 0) {
      transformations.add(new LimitPushdownOptimizer());
    }
    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPTIMIZE_LIMIT)) {
      transformations.add(new OrderlessLimitPushDownOptimizer());
    }
    if(HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPTIMIZE_METADATA_QUERIES)) {
      transformations.add(new StatsOptimizer());
    }
    if (pctx.getContext().isExplainSkipExecution() && !isTezExecEngine) {
      transformations.add(new AnnotateWithStatistics());
      transformations.add(new AnnotateWithOpTraits());
    }

    if (!HiveConf.getVar(hiveConf, HiveConf.ConfVars.HIVE_FETCH_TASK_CONVERSION).equals("none")) {
      transformations.add(new SimpleFetchOptimizer()); // must be called last
    }

    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_FETCH_TASK_AGGR)) {
      transformations.add(new SimpleFetchAggregation());
    }

    if (HiveConf.getBoolVar(hiveConf, HiveConf.ConfVars.HIVE_OPTIMIZE_TABLE_PROPERTIES_FROM_SERDE)) {
      transformations.add(new TablePropertyEnrichmentOptimizer());
    }

  }