Paul Ramsey writes:
>> On Mar 5, 2019, at 3:56 PM, Tom Lane wrote:
>> Then you're at least missing adequate tests for the 3-arg functions...
>> 3 args with the index column second will not work as this stands.
> Some of the operators are indifferent to order (&&, overlaps) and others are
>
> On Mar 5, 2019, at 3:56 PM, Tom Lane wrote:
>
> Paul Ramsey writes:
>> On Mar 5, 2019, at 3:26 PM, Tom Lane wrote:
>>> Hm, I think your addition of this bit is wrong:
>>>
>>> +/*
>>> +* Arguments were swapped to put the index value on the
>>> +
Paul Ramsey writes:
> On Mar 5, 2019, at 3:26 PM, Tom Lane wrote:
>> Hm, I think your addition of this bit is wrong:
>>
>> +/*
>> +* Arguments were swapped to put the index value on the
>> +* left, so we need the commutated operator
> On Mar 5, 2019, at 3:26 PM, Tom Lane wrote:
>
> Paul Ramsey writes:
>> Thanks for the patch, I’ve applied and smoothed and taken your advice on
>> schema-qualified lookups as well.
>
> Hm, I think your addition of this bit is wrong:
>
> +/*
> +*
Paul Ramsey writes:
> Thanks for the patch, I’ve applied and smoothed and taken your advice on
> schema-qualified lookups as well.
Hm, I think your addition of this bit is wrong:
+/*
+* Arguments were swapped to put the index value on the
+
Paul Ramsey writes:
>> On Mar 4, 2019, at 2:52 PM, Tom Lane wrote:
>> BTW, if you'd like me to review the code you added for this, I'd be happy
>> to do so. I've never looked at PostGIS' innards, but probably I can make
>> sense of the code for this despite that.
> I would be ecstatic for a
> On Mar 4, 2019, at 2:52 PM, Tom Lane wrote:
>
> Paul Ramsey writes:
>> Gotcha, done and now have an implementation that passes all our regression
>> tests.
>
> Very cool! So the next step, I guess, is to address your original problem
> by cranking up the cost estimates for these
Paul Ramsey writes:
> Gotcha, done and now have an implementation that passes all our regression
> tests.
Very cool! So the next step, I guess, is to address your original problem
by cranking up the cost estimates for these functions --- have you tried
that yet? In principle you should be
Paul Ramsey writes:
> I had what seemed to be working code except for a couple rare cases,
> but when I fixed those cases it turned out that I had a major problem:
> building a OP expression works fine, but building a
> OP expression returns me an error.
Yup, you're not supposed to do that.
So I am getting much closer to a working implementation in PostGIS,
but have just run into an issue which I am assuming is my
misunderstanding something...
https://github.com/pramsey/postgis/blob/92268c94f3aa1fc63a2941f2b451be15b28662cf/postgis/gserialized_supportfn.c#L287
I had what seemed to
Paul Ramsey writes:
> I added three indexes to my test table:
> CREATE INDEX foo_g_gist_x ON foo USING GIST (g);
> CREATE INDEX foo_g_gist_nd_x ON foo USING GIST (g gist_geometry_ops);
> CREATE INDEX foo_g_spgist_x ON foo USING SPGIST (g);
> They all support the overlaps (&&) operator.
>
> On Feb 27, 2019, at 3:40 PM, Tom Lane wrote:
>
>> Variable SupportRequestCost is very exciting, but given that variable cost
>> is usually driven by the complexity of arguments, what kind of argument is
>> the SupportRequestCost call fed during the planning stage? Constant
>> arguments
Paul Ramsey writes:
> The documentation says that a support function should have a signature
> "supportfn(internal) returns internal”, but doesn’t say which (if any)
> annotations should be provided. IMMUTABLE? PARALLEL SAFE? STRICT? None? All?
It doesn't matter much given that these things
A few more questions…
The documentation says that a support function should have a signature
"supportfn(internal) returns internal”, but doesn’t say which (if any)
annotations should be provided. IMMUTABLE? PARALLEL SAFE? STRICT? None? All?
Variable SupportRequestCost is very exciting, but
Paul Ramsey writes:
>> On Feb 26, 2019, at 2:19 PM, Tom Lane wrote:
>> In most cases, multiple matching arguments are going to lead to
>> failure to construct any useful index condition, because your
>> comparison value has to be a pseudoconstant (ie, not a variable
>> from the same table, so in
> On Feb 26, 2019, at 2:19 PM, Tom Lane wrote:
>
> In most cases, multiple matching arguments are going to lead to
> failure to construct any useful index condition, because your
> comparison value has to be a pseudoconstant (ie, not a variable
> from the same table, so in both of the above
Paul Ramsey writes:
> On Feb 26, 2019, at 2:19 PM, Tom Lane wrote:
>> What's the query look like exactly? The other two calls will occur
>> anyway, but SupportRequestIndexCondition depends on the function
>> call's placement.
> select geos_intersects_new(g, 'POINT(0 0)') from foo;
Right, so
> On Feb 26, 2019, at 2:19 PM, Tom Lane wrote:
>
>> I have
>> created a table (foo) a geometry column (g) and an index (GIST on
>> foo(g)) and am running a query against foo using a noop function with
>> a support function bound to it.
>
>> The support function is called, twice, once in
>>
Paul Ramsey writes:
> New line of questioning: under what conditions will the support
> function be called in a T_SupportRequestIndexCondition mode?
It'll be called if the target function appears at top level of a
WHERE or JOIN condition and any one of the function's arguments
syntactically
On Mon, Feb 25, 2019 at 4:09 PM Tom Lane wrote:
>
> Paul Ramsey writes:
> > On Mon, Feb 25, 2019 at 3:01 PM Tom Lane wrote:
> >> It's whichever one the index column's opclass belongs to. Basically what
> >> you're trying to do here is verify whether the index will support the
> >> optimization
Paul Ramsey writes:
> On Mon, Feb 25, 2019 at 3:01 PM Tom Lane wrote:
>> It's whichever one the index column's opclass belongs to. Basically what
>> you're trying to do here is verify whether the index will support the
>> optimization you want to perform.
> * If I have tbl1.geom
> * and I have
On Mon, Feb 25, 2019 at 3:01 PM Tom Lane wrote:
> > Looking at the examples, they are making use of the opfamily that
> > comes in SupportRequestIndexCondition.opfamily.
> > That opfamily Oid is the first one in the IndexOptInfo.opfamily array.
> > Here's where my thread of understanding fails
Paul Ramsey writes:
> So... trying to figure out how to use SupportRequestIndexCondition to
> convert a call to Intersects() in to a call that also has the operator
> && as well.
OK.
> Looking at the examples, they are making use of the opfamily that
> comes in
On Mon, Jan 28, 2019 at 9:51 AM Tom Lane wrote:
> is people like PostGIS, who already cleared that bar. I hope that
> we'll soon have a bunch of examples, like those in the 0004 patch,
> that people can look at to see how to do things in this area. I see
> no reason to believe it'll be all that
Simon Riggs writes:
> On Tue, 29 Jan 2019 at 09:55, Tom Lane wrote:
>> I have no particular
>> interest in working on that right now, because it doesn't respond to
>> what I understand PostGIS' need to be, and there are only so many
>> hours in the day. But maybe it could be made workable in
On Tue, 29 Jan 2019 at 09:55, Tom Lane wrote:
> Simon Riggs writes:
> > On Sun, 27 Jan 2019 at 19:17, Tom Lane wrote:
> >> ... I don't
> >> know whether that would satisfy your concern, because I'm not clear
> >> on what your concern is.
>
> > To be able to extract indexable clauses where none
Simon Riggs writes:
> On Sun, 27 Jan 2019 at 19:17, Tom Lane wrote:
>> ... I don't
>> know whether that would satisfy your concern, because I'm not clear
>> on what your concern is.
> To be able to extract indexable clauses where none existed before.
That's a pretty vague statement, because it
On Sun, 27 Jan 2019 at 19:17, Tom Lane wrote:
> > * Allow a normal term to match a functional index, e.g. WHERE x =
> > 'abcdefgh' => WHERE substr(x, 1 , 5) = 'abcde' AND x = 'abcdefgh'
>
> I'm a bit confused about what you think this example means. I do
> intend to work on letting extensions
Robert Haas writes:
> On Sat, Jan 26, 2019 at 12:35 PM Tom Lane wrote:
>> Attached is an 0004 that makes a stab at providing some intelligence
>> for unnest() and the integer cases of generate_series().
> That looks awesome.
> I'm somewhat dubious about whole API. It's basically -- if you
On Sat, Jan 26, 2019 at 12:35 PM Tom Lane wrote:
> Attached is an 0004 that makes a stab at providing some intelligence
> for unnest() and the integer cases of generate_series().
That looks awesome.
I'm somewhat dubious about whole API. It's basically -- if you have a
problem and a PhD in
Simon Riggs writes:
> On Sun, 20 Jan 2019 at 23:48, Tom Lane wrote:
>> What I'm envisioning therefore is that we allow an auxiliary function ...
> Does this help with these cases?
> * Allow a set returning function to specify number of output rows, in cases
> where that is variable and
On Sun, 20 Jan 2019 at 23:48, Tom Lane wrote:
> What I'm envisioning therefore is that we allow an auxiliary function to
> be attached to any operator or function that can provide functionality
> like this, and that we set things up so that the set of tasks that
> such functions can perform can
I wrote:
> There's a considerable amount of follow-up work that ought to happen
> now to make use of these capabilities for places that have been
> pain points in the past, such as generate_series() and unnest().
> But I haven't touched that yet.
Attached is an 0004 that makes a stab at providing
Over in the thread at [1], we realized that PostGIS has been thrashing
around trying to fake its way to having "special index operators", ie
a way to automatically convert WHERE clauses into lossy index quals.
That's existed in a non-extensible way inside indxpath.c for twenty
years come July.
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