Develop independently and intelligently

Develop independently and intelligently

Recently, I checked the statements that run on the database for a long time and found that the developers on our side are really amazing, and the skills they do not understand are really high.

The development thought that the index would be fast, and the index hint could be forced to take the index, so it was used. However, bitmap index full scan scans the entire index, and converts the bitmap conversion to rowids to THE rowid, then, data (table access by index rowid) is obtained from the table based on the rowid of the index and the rowid of the table ).

Since we find all the data in the table from all rowids in the index, isn't it faster to scan the whole table without scanning the whole table directly? Don't be silly about oracle. After I remove the index hint, I use a full table scan. That's right.

The read index is a single read, and the return table is also a single read. A single read operation is similar to a multi-read operation. Obviously, multiple reads are scanned at a time.

As for optimization, it is easy to remove the index hint. If the table is large, it is OK to add parallel statements.

What does self-smart self-work mean?

Self-thinking.

Self-developed z branch zu Branch c branch ng míng
Explanation-English Translation
Intelligent Chinese explanation
The following results are provided in the Chinese dictionary.
[Explanation]: He thinks he is smart and does not make his claim. It means to estimate yourself in height and handle affairs subjectively.
[From]: Shang Shu-cai zhongzhi's life: "No Wise, no old chapter ." Song hongmai Volume 14: "Yanzhou PiXian County, the amount of Grass" points "word, the county order Self-made smart, that is, the grass is not suitable, from the real book three words carved up ."
[Synonym]: Shift axe, self-righteous, and postpaid
[Antonym]: Non-or self-knowledge
[Syntax]: The subject-verb type, which is a predicate, attribute, and predicator. It contains negative meanings.

Intelligent English Translation
The following results are explained in the dictionary by the Dian Tong.
1. to think oneself clever; to fancy oneself smart; to be wise in one's own conceit2.presumptuous; smart-alecky

Smart stories

In my opinion, "hiding your ears and stealing your ears", "a blind eye", "waiting for a rabbit", "seeking for a sword", and "pulling up the seedlings" are all stories of self-made intelligence.