Re: Logical tape pause/resume

Claudio Freire <klaussfreire@gmail.com>

From: Claudio Freire <klaussfreire@gmail.com>
To: Heikki Linnakangas <hlinnaka@iki.fi>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>, Peter Geoghegan <pg@heroku.com>
Date: 2016-10-04T16:06:48Z
Lists: pgsql-hackers
On Tue, Oct 4, 2016 at 7:47 AM, Heikki Linnakangas <hlinnaka@iki.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?


Commits

  1. Simplify tape block format.