message: Issue Make GetChunk cost
  Remove unnecessary lock on thread-local object.
diff: @@ -10,9 +10,6 @@ public:
  : PhysicalOperatorState(op, child), expression_index(0) {
  }
  - //! Thread safety
  - mutex lock;
  -
  //! The current position in the scan
  idx_t expression_index;
  @@ -27,8 +24,6 @@ void PhysicalExpressionScan::GetChunkInternal(ExecutionContext &context, DataChu
  return;
  }
  - {
  - lock_guard<mutex> slock(state->lock);
  if (state->expression_index == 0) {
  // first run, fetch the chunk from the child
  D_ASSERT(children.size() == 1);
  @@ -37,9 +32,7 @@ void PhysicalExpressionScan::GetChunkInternal(ExecutionContext &context, DataChu
  return;
  }
  }
  - }
  // now execute the expressions of the nth expression list for the child chunk list
  - // These are scanned in parallel, so the mutability is not an issue?
  state->executor = make_unique<ExpressionExecutor>(expressions[state->expression_index]);
  state->executor->Execute(state->child_chunk, chunk);
  