Affects Version/s: None
Fix Version/s: None
Before we can start working on Hive-461. I am doing some profiling for hive. And here are some thoughts for improvements:
1) add a new HiveText to replace Text. It can avoid byte copy when init LazyString. I have done a draft one, it shows ~1% performance gains.
2) let StructObjectInspector's
In my profiling test, it shows some performace gains. but in acutal execution it did not. Anyway, let it return java array will reduce gc's burden of collection ArrayList
not so minor:
3) split FileSinkOperator's Writer into another Thread. Adding a producer-consumer array as the bridge between the Operators thread and the Writer thread.
4) the operator stack is kind of deep. In order to avoid instruction cache misses, and increase the efficiency data cache, I suggest to let Hive's operator can process an array of rows instead of processing only one row at a time.