Re: Free Space Map data structure
| От | Dave Page |
|---|---|
| Тема | Re: Free Space Map data structure |
| Дата | |
| Msg-id | 937d27e10804080159i10e9bacckeeb7404ec5374835@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Free Space Map data structure ("Brendan Jurd" <direvus@gmail.com>) |
| Список | pgsql-hackers |
On Tue, Apr 8, 2008 at 9:54 AM, Brendan Jurd <direvus@gmail.com> wrote: > If I understand your design correctly, this claim isn't true. If the > topmost node reports 9 bytes free, could you not have seven pages each > with 1 byte free, and an eighth page with 2 bytes free? > > 9 > 4 5 > 2 2 2 3 > 1 1 1 1 1 1 1 2 > > So you'd actually end up walking two levels down the left hand side of > the tree, discovering not enough space, and then walking two levels > down the right hand side to again discover not enough space. As I read it, each node takes the value of the largest child, not the sum of the children. -- Dave Page EnterpriseDB UK: http://www.enterprisedb.com
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