This feels overengineered and it kinda is, but other efforts to
inroduce sequential naming/UUID naming haven't been that fruitful
either.
10 character random "hash" i now changed to.
1. first character - last character in UUID4 ID of request/job
2. three characters - derived from current timestamp.
4. 6 characters - random data.
This satisfies all three requirements:
1. Readers - temporal locality should result in spatial locality on disk. (fewer pages accessed)
2. Single writer - temporal locality should result in spatial locality. (fewer dirty pages)
3. Multiple writers - temporal locality should NOT result in spatial locality. (less lock contention)
Mostly concludes https://github.com/frappe/frappe/pull/25309 and https://github.com/frappe/frappe/pull/28349
Rough probabiliy numbers
Assumptions:
- Unique per worker prefix - 16 (uuid's base16 version)
- Rough time spent generating names - 10% of request (very very conservative estimate)
Probability(collision) = P(at least one prefix collision) * P(time collision)
Probability(collision) = (1 - p(all different)) * 10%
Probability(collision) = (1 - (16! / 16-N! )/ 16^N ) * 10%
| N (concurrency) | Probability(collision) |
| 1 | 0.0% |
| 2 | 0.6% |
| 3 | 1.8% |
| 4 | 3.3% |
| 5 | 5.0% |
| 6 | 6.6% |
| 7 | 7.9% |
| 8 | 8.8% |
Added slots for these classes:
- Session - Created on EACH request
- LoginManager - Created on each request
- Monitor - Created on each request if monitor is enabled (usually in
prod setup)
refactor: clean up code to py39+ supported syntax
- f-strings instead of format
- latest typing support instead of pre 3.9 TitleCase
- remove UTF-8 declarations.
- many more changes
Powered by https://github.com/asottile/pyupgrade/ + manual cleanups
The license.txt file has been replaced with LICENSE for quite a while
now. INAL but it didn't seem accurate to say "hey, checkout license.txt
although there's no such file". Apart from this, there were
inconsistencies in the headers altogether...this change brings
consistency.
* Remove six for PY2 compatability since our dependencies are not, PY2
is legacy.
* Removed usages of utils from future/past libraries since they are
deprecated. This includes 'from __future__ ...' and 'from past...'
statements.
* Removed compatibility imports for PY2, switched from six imports to
standard library imports.
* Removed utils code blocks that handle operations depending on PY2/3
versions.
* Removed 'from __future__ ...' lines from templates/code generators
* Used PY3 syntaxes in place of PY2 compatible blocks. eg: metaclass
