Re: Relation extension scalability

On Thu, Mar 24, 2016 at 6:13 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
wrote:

>
> 1.
> +GetPageWithFreeSpaceUsingOldPage(Relation rel, BlockNumber oldPage,
> + Size spaceNeeded)
> {
> ..
> + /*
> + * If fsm_set_and_search found a suitable new block, return that.
> + * Otherwise, search as usual.
> + */
> ..
> }
>
> In the above comment, you are referring wrong function.
>

Fixed

>
> 2.
> +static int
> +fsm_search_from_addr(Relation rel, FSMAddress addr, uint8 minValue)
> +{
> + Buffer buf;
> + int newslot = -1;
> +
> + buf = fsm_readbuf(rel, addr, true);
> + LockBuffer(buf, BUFFER_LOCK_SHARE);
> +
> + if (minValue != 0)
> + {
> + /* Search while we still hold the lock */
> + newslot = fsm_search_avail(buf, minValue,
> + addr.level == FSM_BOTTOM_LEVEL,
> + false);
>
> In this new API, I don't understand why we need minValue != 0 check,
> basically if user of API doesn't want to search for space > 0, then what is
> the need of calling this API? I think this API should use Assert for
> minValue!=0 unless you see reason for not doing so.
>
>
Agree, it should be assert.

> >
> > GetNearestPageWithFreeSpace? (although not sure that's accurate
> description, maybe Nearby would be better)
> >
>
> Better than what is used in patch.
>
> Yet another possibility could be to call it as
> GetPageWithFreeSpaceExtended and call it from GetPageWithFreeSpace with
> value of oldPage as InvalidBlockNumber.
>

Yes I like this.. Changed the same.

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com