List<Iterable<Block>> sources = sourcesBuilder.build();
ColumnFileHandle targetFileHandle = builder.build();
if (!sources.isEmpty()) {
// Throw out any stats generated by the optimization step
ConnectorSession session = new ConnectorSession("user", "source", "catalog", "schema", UTC_KEY, Locale.ENGLISH, "address", "agent");
OperatorContext operatorContext = new TaskContext(new TaskId("query", "stage", "task"), executor, session)
.addPipelineContext(true, true)
.addDriverContext()
.addOperatorContext(0, "OptimizeEncodings");