| From: | Claudio Freire <klaussfreire(at)gmail(dot)com> |
|---|---|
| To: | Heikki Linnakangas <hlinnaka(at)iki(dot)fi> |
| Cc: | pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Peter Geoghegan <pg(at)heroku(dot)com> |
| Subject: | Re: Logical tape pause/resume |
| Date: | 2016-10-04 16:06:48 |
| Message-ID: | CAGTBQpYz7c1N+W1ggbJ_VBmwSvM28pHFEqn3VipL0QdTeiwT8A@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Tue, Oct 4, 2016 at 7:47 AM, Heikki Linnakangas <hlinnaka(at)iki(dot)fi> wrote:
> 1. The first patch changes the way we store the logical tapes on disk.
> Instead of using indirect blocks, HFS style, the blocks form a linked list.
> Each block has a trailer, with the block numbers of the previous and next
> block of the tape. That eliminates the indirect blocks, which simplifies the
> code quite a bit, and makes it simpler to implement the pause/resume
> functionality in the second patch. It also immediately reduces the memory
> needed for the buffers, from 3 to 1 block per tape, as we don't need to hold
> the indirect blocks in memory.
Doesn't that make prefetching more than a buffer ahead harder?
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