io.prestosql.sql.planner.optimizations

Class UnaliasSymbolReferences

java.lang.Object

io.prestosql.sql.planner.optimizations.UnaliasSymbolReferences

All Implemented Interfaces:

PlanOptimizer

public class UnaliasSymbolReferences
extends Object
implements PlanOptimizer

Re-maps symbol references that are just aliases of each other (e.g., due to projections like $0 := $1)

E.g.,

Output[$0, $1] -> Project[$0 := $2, $1 := $3 * 100] -> Aggregate[$2, $3 := sum($4)] -> ...

gets rewritten as

Output[$2, $1] -> Project[$2, $1 := $3 * 100] -> Aggregate[$2, $3 := sum($4)] -> ...

Constructor Summary

Constructors

Constructor and Description
UnaliasSymbolReferences()

Method Summary

Modifier and Type	Method and Description
PlanNode	optimize(PlanNode plan, Session session, TypeProvider types, SymbolAllocator symbolAllocator, PlanNodeIdAllocator idAllocator, WarningCollector warningCollector)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

UnaliasSymbolReferences

public UnaliasSymbolReferences()

Method Detail

optimize

public PlanNode optimize(PlanNode plan,
                         Session session,
                         TypeProvider types,
                         SymbolAllocator symbolAllocator,
                         PlanNodeIdAllocator idAllocator,
                         WarningCollector warningCollector)

Specified by:

optimize in interface PlanOptimizer