Индексы

https://architecturenotes.co/things-you-should-know-about-databases/

Как индексы хранятся в памяти

Now reading in that small amount of data into memory is quite fast and relatively trivial to scan. Now what if the data we are searching across can't be cached entirely in memory? or the time to read all the data from disk is taking too long?

+──────────+─────────+───────────────────+
| id       | name    | city              |
+──────────+─────────+───────────────────+
| 1        | Mahdi   | Ottawa            |
| 2        | Elon    | Mars              |
| 3        | Jeff    | Orbit             |
| 4        | Klay    | Oakland           |
| 5        | Lebron  | Los Angeles       |
| ...      | ...     | ...               |
| 1000000  | Steph   | San Francisco     |
| 1001000  | Linus   | Portland          |
+───────+─────────+──────────────────────+