Friday, August 29, 2008

Re: [HACKERS] New FSM allocation policy

Gregory Stark <stark@enterprisedb.com> writes:
> One idea, we could scan the rest of the current page and use the first match.

> Another, given the way your tree structure works you can also descend the tree
> with a "target" page. You can find the first page with enough free space after
> the target page if there are any. (Take left branch if it's > target and has
> enough free space else take right branch if there's enough free space else
> take left branch).

I think the trick here is how to also preserve the property that
different backends tend to be inserting into different pages. There may
be no very good way to do that without maintaining some shared state,
ie the last page handed out.

However, it would probably be sufficient to do that for some pretty
small number of tables, allowing a fixed-size shared memory area to be
sufficient.

regards, tom lane

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