[Question] Is there a problem with SQL parse and compile in this diagram 101?

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Original topic: 【提问】101这个图里sql parse和compile是不是有点问题啊

| username: TiDBer_H5NdJb5Q

In the image, the AST is output during the preprocess stage of the compile module, but according to the documentation, it should be output by the parse interface. Is there a problem with the PPT?

| username: WinterLiu | Original post link

Don’t worry about these details, once you finish learning, you won’t need them anymore :grin:

| username: TiDBer_H5NdJb5Q | Original post link

It’s because I had this question in the PCTA exam the day before yesterday. Although I passed, I checked it again after the exam and I’m still not quite sure :smile:

| username: tidb菜鸟一只 | Original post link

Not just this issue, the time to obtain TSO in the diagram is also incorrect. TSO should be obtained during the execution phase.

| username: xfworld | Original post link

Both stages involve AST processing, but the details are different.

During compilation, statistical information is added. Preprocessing will decompose the AST from the previous parsing step into two different processing rules:

  • PointGet BatchPointGet
  • QueryGet operator pushdown, etc.

The optimization directions will also differ.