On Jul 27, 2007, at 1:49 AM, Alvaro Herrera wrote:
ITAGAKI Takahiro wrote:
"Simon Riggs" <[EMAIL PROTECTED]> wrote:

Read the heap blocks in sequence, but make a conditional lock for
cleanup on each block. If we don't get it, sleep, then try again when we
wake up. If we fail the second time, just skip the block completely.

It would be cool if we could do something like sweep a range of pages,
initiate IO for those that are not in shared buffers, and while that is running, lock and clean up the ones that are in shared buffers, skipping
those that are not lockable right away; when that's done, go back to
those buffers that were gotten from I/O and clean those up.  And retry
the locking for those that couldn't be locked the first time around,
also conditionally.  And when that's all done, a third pass could get
those blocks that weren't cleaned up in none of the previous passes (and
this time the lock would not be conditional).

Would that be substantially easier than just creating a bgreader?
Jim Nasby                                            [EMAIL PROTECTED]
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)

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