(2014/08/21 13:21), Ashutosh Bapat wrote:
On Wed, Aug 20, 2014 at 3:25 PM, Etsuro Fujita
<fujita.ets...@lab.ntt.co.jp <mailto:fujita.ets...@lab.ntt.co.jp>> wrote:
Hi Ashutish,
I am sorry that I mistook your name's spelling.
(2014/08/14 22:30), Ashutosh Bapat wrote:
On Thu, Aug 14, 2014 at 10:05 AM, Etsuro Fujita
<fujita.ets...@lab.ntt.co.jp
<mailto:fujita.ets...@lab.ntt.co.jp>
<mailto:fujita.ets...@lab.ntt.__co.jp
<mailto:fujita.ets...@lab.ntt.co.jp>>> wrote:
(2014/08/08 18:51), Etsuro Fujita wrote:
>>> (2014/06/30 22:48), Tom Lane wrote:
>>>> I wonder whether it isn't time to change that. It
was coded
like that
>>>> originally only because calculating the values
would've been a
waste of
>>>> cycles at the time. But this is at least the third place
where it'd be
>>>> useful to have attr_needed for child rels.
There was a problem with the previous patch, which will be
described
below. Attached is the updated version of the patch
addressing that.
Here are some more comments
attr_needed also has the attributes used in the restriction
clauses as
seen in distribute_qual_to_rels(), so, it looks unnecessary to call
pull_varattnos() on the clauses in baserestrictinfo in functions
check_selective_binary___conversion(),
remove_unused_subquery___outputs(),
check_index_only().
IIUC, I think it's *necessary* to do that in those functions since
the attributes used in the restriction clauses in baserestrictinfo
are not added to attr_needed due the following code in
distribute_qual_to_rels.
That's right. Thanks for pointing that out.
Although in case of RTE_RELATION, the 0th entry in attr_needed
corresponds to FirstLowInvalidHeapAttributeNu__mber + 1, it's
always safer
to use it is RelOptInfo::min_attr, in case get_relation_info()
wants to
change assumption or somewhere down the line some other part of code
wants to change attr_needed information. It may be unlikely, that it
would change, but it will be better to stick to comments in
RelOptInfo
443 AttrNumber min_attr; /* smallest attrno of rel
(often
<0) */
444 AttrNumber max_attr; /* largest attrno of rel */
445 Relids *attr_needed; /* array indexed [min_attr ..
max_attr] */
Good point! Attached is the revised version of the patch.
If the patch is not in the commit-fest, can you please add it there?
I've already done that:
https://commitfest.postgresql.org/action/patch_view?id=1529
From my side, the review is done, it should be marked "ready for
committer", unless somebody else wants to review.
Many thanks!
Best regards,
Etsuro Fujita
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