Re: A worst case for qsort
| От | Rod Taylor |
|---|---|
| Тема | Re: A worst case for qsort |
| Дата | |
| Msg-id | CAKddOFAfkp_3M7k+-==qcGO8FRPX=6QP9FNtsSwCMFM+pZdpiA@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: A worst case for qsort (Rod Taylor <rod.taylor@gmail.com>) |
| Ответы |
Re: A worst case for qsort
|
| Список | pgsql-hackers |
Sigh. Found another example.
A table with 15 million entries and a unique key on filesystem location for things users created via a web interface.
Entries all begin with /usr/home/ ...
Entries all begin with /usr/home/ ...
This one is frequently sorted as batch operations against the files are performed in alphabetical order to reduce conflict issues that a random ordering may cause between jobs.
regards,
Rod
regards,
Rod
On Thu, Aug 7, 2014 at 5:23 PM, Rod Taylor <rod.taylor@gmail.com> wrote:
On Thu, Aug 7, 2014 at 3:06 PM, Peter Geoghegan <pg@heroku.com> wrote:I think that pre-sorted, all-unique text datums, that have all
differences beyond the first 8 bytes, that the user happens to
actually want to sort are fairly rare.While I'm sure it's not common, I've seen a couple of ten-million tuple tables having a URL column as primary key where 98% of the entries begin with 'http://www.'So, that exact scenario is out there.
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