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Re: Copy entire table - Follow on question - Whats up with the numbering
Posted by: Agostino di Salle
Date: April 26, 2022 11:30AM

We see the same issue using innodb table with mysql 8.0.28

when doing LOAD DATA or INSERT INTO ... SELECT FROM, if you insert n rows mysql allocate auto increment ids rounding n (the number of rows) to the next power of 2 - 1.

example:
- file rows between 2 and 3, allocated auto_increment ids: 3
- file rows between 4 and 7, allocated auto_increment ids: 7
- file rows between 8 and 15, allocated auto_increment ids: 15
- file rows between 15 and 31, allocated auto_increment ids: 31
- ....
- file rows between 512 and 1023, allocated auto_increment ids: 1023
- file rows between 1024 and 2047, allocated auto_increment ids: 2047

if n is the number of rows and b is the number of bits to represent n, the allocated auto increment ids seems to be: (2 ^ b) - 1

If you load exactly 1,3,7,15,31,63,127,255,511,1023,... rows no auto_increment ids seems to be "lost".

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