How is the memset in select_rtable_names_for_explain a dead-store? Even memset calls could be optimized away from the EXPLAIN codepath I have a feeling it
would have to be many in a tight loop for it to be measurable even?
--
Daniel Gustafsson
For the first question, I don't mean that the memset is the dead store. I mean that the stores with value "0" after the memset are dead:
```
dpns.subplans = NIL;
dpns.ctes = NIL;
dpns.appendrels = NULL;
```
since the memset has written zeroes to the object "dpns", and these members are known to be zero.
For the second question, you are right, I don't really profile it or measure the performance impact for it. I just think it's worthwhile to improve codegen quality without affecting readability, as adopting performance tips from some static analyzer.
Best regards, Hongyu.