On 12/17/2013 04:55 AM, Jim Nasby wrote:
On 11/9/13, 10:02 AM, Heikki Linnakangas wrote:
3. Another approach would be to get rid of the "can't delete
rightmost child" limitation. We currently have that limitation
because it ensures that we never need to change the high-key of a
page. If we delete a page that is the rightmost child of its
parent, we transfer the deleted keyspace from the parent page to
its right sibling. To do that, we need to update the high key of
the parent, as well as the downlink of the right sibling at the
grandparent level. That's a bit complicated, because updating the
high key might require splitting the page.
Is the rightmost child issue likely to affect indexes on increasing
values, like a queue table?
No. In a FIFO queue, you keep adding new items to the right-end of the
index, so old pages become non-rightmost fairly quickly.
- Heikki
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