Re: Small patch for GiST: move childoffnum to child

On 14.07.2011 13:29, Alexander Korotkov wrote:
> On Thu, Jul 14, 2011 at 12:56 PM, Heikki Linnakangas<
> heikki.linnakangas@enterprisedb.com>  wrote:
>
>> First, notice that we're setting "ptr->parent = top". 'top' is the current
>> node we're processing, and ptr represents the node to the right of the
>> current node. The current node is *not* the parent of the node to the right.
>> I believe that line should be "ptr->parent = top->parent".
>>
> I think same.
>
>> Second, we're adding the entry for the right sibling to the end of the list
>> of nodes to visit. But when we process entries from the list, we exit
>> immediately when we see a leaf page. That means that the right sibling can
>> get queued up behind leaf pages, and thus never visited.
>
> I think possible solution is to save right sibling immediatly after current
> page . Thus, this code fragment should looks like this:
>
>
>>                 if (top->parent&&  XLByteLT(top->parent->lsn,
>> GistPageGetOpaque(page)->nsn)&&
>>                         GistPageGetOpaque(page)->**rightlink !=
>> InvalidBlockNumber /* sanity check */ )
>>                 {
>>                         /* page splited while we thinking of... */
>>                         ptr = (GISTInsertStack *) palloc0(sizeof(**
>> GISTInsertStack));
>>                         ptr->blkno = GistPageGetOpaque(page)->**rightlink;
>>                         ptr->childoffnum = InvalidOffsetNumber;
>>                         ptr->parent = top->parent;
>>                         ptr->next = top->next;
>>                         top->next = ptr;
>>                         if (tail == top);
>>                                 tail = ptr;
>
>                  }

Agreed, committed. Thanks for verifying my thinking.

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com