presto-main/src/main/java/io/prestosql/sql/gen/JoinFilterFunctionCompiler.java/JoinFilterFunctionCompiler/JoinFilterCacheKey
class JoinFilterFunctionCompiler:        public JoinFilterCacheKey(RowExpression filter, int leftBlocksSize)
        {
            this.filter = requireNonNull(filter, "filter can not be null");
            this.leftBlocksSize = leftBlocksSize;
        }