Here is a patch that changes the generating of message IDs:

1. The datetime is taken with higher precision, 2 decimal digits after dot.
2. The datetime is written as Unix time in 0.01 second units, not as YYYYmmddHHMMSS. This is more compact and faster.
3. The random part is taken as the random integer in the range 0 from to 2**64, not from 0 to 10**5.

This increases the length of generated part of the ID from 26 to 39 characters in average. Perhaps in new releases we can use non-decimal or even non-alphanumeric characters in ID for compactness.