# Big Todos for CIDR:

- [ ] Clone the main [Spark Optimizer Rules](https://github.com/apache/spark/blob/master/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala#L72)
    - [x] PushProjectionThroughUnion,
    - [x] PushProjectionThroughLimit,
    - [x] ReorderJoin,
    - [x] EliminateOuterJoin,
    - [ ] PushDownPredicates,
    - [ ] PushDownLeftSemiAntiJoin,
    - [ ] PushLeftSemiLeftAntiThroughJoin,
    - [ ] LimitPushDown,
    - [ ] LimitPushDownThroughWindow,
    - [ ] ColumnPruning,
    - [ ] GenerateOptimization,
    - [ ] CollapseRepartition,
    - [ ] CollapseProject,
    - [ ] OptimizeWindowFunctions,
    - [ ] CollapseWindow,
    - [ ] EliminateOffsets,
    - [ ] EliminateLimits,
    - [ ] CombineUnions,
    - [ ] OptimizeRepartition,
    - [ ] TransposeWindow,
    - [ ] NullPropagation,
    - [ ] NullDownPropagation,
    - [ ] ConstantPropagation,
    - [ ] FoldablePropagation,
    - [ ] OptimizeIn,
    - [ ] OptimizeRand,
    - [ ] ConstantFolding,
    - [ ] EliminateAggregateFilter,
    - [ ] ReorderAssociativeOperator,
    - [ ] LikeSimplification,
    - [ ] BooleanSimplification,
    - [ ] SimplifyConditionals,
    - [ ] PushFoldableIntoBranches,
    - [ ] RemoveDispensableExpressions,
    - [ ] SimplifyBinaryComparison,
    - [ ] ReplaceNullWithFalseInPredicate,
    - [ ] PruneFilters,
    - [ ] SimplifyCasts,
    - [ ] SimplifyCaseConversionExpressions,
    - [ ] RewriteCorrelatedScalarSubquery,
    - [ ] RewriteLateralSubquery,
    - [ ] EliminateSerialization,
    - [ ] RemoveRedundantAliases,
    - [ ] RemoveRedundantAggregates,
    - [ ] UnwrapCastInBinaryComparison,
    - [ ] RemoveNoopOperators,
    - [ ] OptimizeUpdateFields,
    - [ ] SimplifyExtractValueOps,
    - [ ] OptimizeCsvJsonExprs,
    - [ ] CombineConcats,
    - [ ] PushdownPredicatesAndPruneColumnsForCTEDef
- [ ] Codegen: Output a Spark-like optimizer based on the above rules
    - [x] Logic generation 
    - [x] Compilation pipeline to streamline testing
    - [ ] Test: Do these rules generate the same results as spark?
- [ ] Apply the rule merge optimization
    - [ ] Generate a merged decision tree
    - [ ] Codegen: Generate a rule for the joint BDD
    - [ ] Test: Do these rules generate the same results as spark?
    - [ ] Test: Can the generated rule be plugged back into spark?
- [ ] Apply the view maintenance optimization
    - [ ] Recursive Pattern-Matching Logic
    - [ ] Codegen: Generate a new optimizer
    - [ ] Test: Do these rules generate the same results as spark?