On 9/3/21 5:56 AM, Justin Pryzby wrote:
On Wed, Sep 01, 2021 at 06:45:29PM +0200, Tomas Vondra wrote:
However while polishing the second patch, I realized we're allowing
statistics on expressions referencing system attributes. So this fails;
CREATE STATISTICS s ON ctid, x FROM t;
but this pass
On Wed, Sep 01, 2021 at 06:45:29PM +0200, Tomas Vondra wrote:
> However while polishing the second patch, I realized we're allowing
> statistics on expressions referencing system attributes. So this fails;
>
> CREATE STATISTICS s ON ctid, x FROM t;
>
> but this passes:
>
> CREATE STATISTICS s ON
On 9/1/21 9:38 PM, Justin Pryzby wrote:
On Wed, Sep 01, 2021 at 06:45:29PM +0200, Tomas Vondra wrote:
Patch 0001 fixes the "double parens" issue discussed elsewhere in this
thread, and patch 0002 tweaks CREATE STATISTICS to treat "(a)" as a simple
column reference.
0002 refuses to create ex
On Wed, Sep 01, 2021 at 06:45:29PM +0200, Tomas Vondra wrote:
> > > Patch 0001 fixes the "double parens" issue discussed elsewhere in this
> > > thread, and patch 0002 tweaks CREATE STATISTICS to treat "(a)" as a simple
> > > column reference.
> >
> > 0002 refuses to create expressional stats on a
On 8/24/21 3:13 PM, Justin Pryzby wrote:
On Mon, Aug 16, 2021 at 05:41:57PM +0200, Tomas Vondra wrote:
This still seems odd:
postgres=# CREATE STATISTICS asf ON i FROM t;
ERROR: extended statistics require at least 2 columns
postgres=# CREATE STATISTICS asf ON (i) FROM t;
CREATE STATISTICS
I
On Mon, Aug 16, 2021 at 05:41:57PM +0200, Tomas Vondra wrote:
> > This still seems odd:
> >
> > postgres=# CREATE STATISTICS asf ON i FROM t;
> > ERROR: extended statistics require at least 2 columns
> > postgres=# CREATE STATISTICS asf ON (i) FROM t;
> > CREATE STATISTICS
> >
> > It seems wrong
On 8/18/21 5:07 AM, Justin Pryzby wrote:
Patch 0001 fixes the "double parens" issue discussed elsewhere in this
thread, and patch 0002 tweaks CREATE STATISTICS to treat "(a)" as a simple
column reference.
From: Tomas Vondra
Date: Mon, 16 Aug 2021 17:19:33 +0200
Subject: [PATCH 2/2] fix: id
> Patch 0001 fixes the "double parens" issue discussed elsewhere in this
> thread, and patch 0002 tweaks CREATE STATISTICS to treat "(a)" as a simple
> column reference.
> From: Tomas Vondra
> Date: Mon, 16 Aug 2021 17:19:33 +0200
> Subject: [PATCH 2/2] fix: identify single-attribute references
On 8/16/21 3:32 AM, Justin Pryzby wrote:
On Mon, Dec 07, 2020 at 03:15:17PM +0100, Tomas Vondra wrote:
Looking at the current behaviour, there are a couple of things that
seem a little odd, even though they are understandable. For example,
the fact that
CREATE STATISTICS s (expressions) ON
On 8/16/21 3:31 AM, Justin Pryzby wrote:
On 1/22/21 5:01 AM, Justin Pryzby wrote:
In any case, why are there so many parentheses ?
On Fri, Jan 22, 2021 at 02:09:04PM +0100, Tomas Vondra wrote:
That's a bug in pg_get_statisticsobj_worker, probably. It shouldn't be
adding extra parentheses,
On Mon, Dec 07, 2020 at 03:15:17PM +0100, Tomas Vondra wrote:
> > Looking at the current behaviour, there are a couple of things that
> > seem a little odd, even though they are understandable. For example,
> > the fact that
> >
> > CREATE STATISTICS s (expressions) ON (expr), col FROM tbl;
> >
On 1/22/21 5:01 AM, Justin Pryzby wrote:
> > In any case, why are there so many parentheses ?
On Fri, Jan 22, 2021 at 02:09:04PM +0100, Tomas Vondra wrote:
> That's a bug in pg_get_statisticsobj_worker, probably. It shouldn't be
> adding extra parentheses, on top of what deparse_expression_pretty
On 6/11/21 6:55 AM, Noah Misch wrote:
On Sun, Jun 06, 2021 at 09:13:17PM +0200, Tomas Vondra wrote:
On 6/6/21 7:37 AM, Noah Misch wrote:
On Sat, Mar 27, 2021 at 01:17:14AM +0100, Tomas Vondra wrote:
OK, pushed after a bit more polishing and testing.
This added a "transformed" field to Cr
On Sun, Jun 06, 2021 at 09:13:17PM +0200, Tomas Vondra wrote:
>
> On 6/6/21 7:37 AM, Noah Misch wrote:
> > On Sat, Mar 27, 2021 at 01:17:14AM +0100, Tomas Vondra wrote:
> >> OK, pushed after a bit more polishing and testing.
> >
> > This added a "transformed" field to CreateStatsStmt, but it didn
Tomas Vondra writes:
> On 6/6/21 9:17 PM, Tom Lane wrote:
>> I'm curious about how come the buildfarm didn't notice this. The
>> animals using COPY_PARSE_PLAN_TREES should have failed. The fact
>> that they didn't implies that there's no test case that makes use
>> of a nonzero value for this fi
On 6/6/21 9:17 PM, Tom Lane wrote:
> Tomas Vondra writes:
>> On 6/6/21 7:37 AM, Noah Misch wrote:
>>> This added a "transformed" field to CreateStatsStmt, but it didn't mention
>>> that field in src/backend/nodes. Should those functions handle the field?
>
>> Yup, that's a mistake - it should
Tomas Vondra writes:
> On 6/6/21 7:37 AM, Noah Misch wrote:
>> This added a "transformed" field to CreateStatsStmt, but it didn't mention
>> that field in src/backend/nodes. Should those functions handle the field?
> Yup, that's a mistake - it should do whatever CREATE INDEX is doing. Not
> sure
On 6/6/21 7:37 AM, Noah Misch wrote:
> On Sat, Mar 27, 2021 at 01:17:14AM +0100, Tomas Vondra wrote:
>> OK, pushed after a bit more polishing and testing.
>
> This added a "transformed" field to CreateStatsStmt, but it didn't mention
> that field in src/backend/nodes. Should those functions han
On Sat, Mar 27, 2021 at 01:17:14AM +0100, Tomas Vondra wrote:
> OK, pushed after a bit more polishing and testing.
This added a "transformed" field to CreateStatsStmt, but it didn't mention
that field in src/backend/nodes. Should those functions handle the field?
On Fri, Jan 22, 2021 at 02:09:04PM +0100, Tomas Vondra wrote:
> On 1/22/21 5:01 AM, Justin Pryzby wrote:
> > On Fri, Jan 22, 2021 at 04:49:51AM +0100, Tomas Vondra wrote:
> > > > > | Statistics objects:
> > > > > | "public"."s2" (ndistinct, dependencies, mcv) ON FROM t
> > >
> > > Umm, for me
I suggest to add some kind of reference to stats expressions here.
--- a/doc/src/sgml/maintenance.sgml
+++ b/doc/src/sgml/maintenance.sgml
Updating Planner Statistics
statistics
of the planner
[...]
@@ -330,10 +330,12 @@
Also, by default there is limited inf
On 3/27/21 1:17 AM, Tomas Vondra wrote:
> On 3/26/21 1:54 PM, Tomas Vondra wrote:
>>
>>
>> On 3/26/21 12:37 PM, Dean Rasheed wrote:
>>> On Thu, 25 Mar 2021 at 19:59, Tomas Vondra
>>> wrote:
Attached is an updated patch series, with all the changes discussed
here. I've cleaned up
On 3/26/21 1:54 PM, Tomas Vondra wrote:
>
>
> On 3/26/21 12:37 PM, Dean Rasheed wrote:
>> On Thu, 25 Mar 2021 at 19:59, Tomas Vondra
>> wrote:
>>>
>>> Attached is an updated patch series, with all the changes discussed
>>> here. I've cleaned up the ndistinct stuff a bit more (essentially
>>> rev
On 3/26/21 12:37 PM, Dean Rasheed wrote:
> On Thu, 25 Mar 2021 at 19:59, Tomas Vondra
> wrote:
>>
>> Attached is an updated patch series, with all the changes discussed
>> here. I've cleaned up the ndistinct stuff a bit more (essentially
>> reverting back from GroupExprInfo to GroupVarInfo name
On Thu, 25 Mar 2021 at 19:59, Tomas Vondra
wrote:
>
> Attached is an updated patch series, with all the changes discussed
> here. I've cleaned up the ndistinct stuff a bit more (essentially
> reverting back from GroupExprInfo to GroupVarInfo name), and got rid of
> the UpdateStatisticsForTypeChang
On Thu, 25 Mar 2021 at 00:05, Tomas Vondra
wrote:
>
> here's an updated patch. 0001
The change to the way that CreateStatistics() records dependencies
isn't quite right -- recordDependencyOnSingleRelExpr() will not create
any dependencies if the expression uses only a whole-row Var. However,
pull
On Thu, 25 Mar 2021 at 00:05, Tomas Vondra
wrote:
>
> Actually, I think we need that block at all - there's no point in
> keeping the exact expression, because if there was a statistics matching
> it it'd be matched by the examine_variable. So if we get here, we have
> to just split it into the va
On 3/25/21 1:05 AM, Tomas Vondra wrote:
> ...
>
> 0002 is an attempt to fix an issue I noticed today - we need to handle
> type changes. Until now we did not have problems with that, because we
> only had attnums - so we just reset the statistics (with the exception
> of functional dependencies, on
On Thu, Mar 25, 2021 at 01:05:37AM +0100, Tomas Vondra wrote:
> here's an updated patch. 0001 should address most of the today's review
> items regarding comments etc.
This is still an issue:
postgres=# CREATE STATISTICS xt ON a FROM t JOIN t ON true;
ERROR: schema "i" does not exist
--
Justin
On 2021-Mar-24, Justin Pryzby wrote:
> On Wed, Mar 24, 2021 at 05:15:46PM +, Dean Rasheed wrote:
> > Hmm, I think "univariate" and "multivariate" are pretty ubiquitous,
> > when used to describe statistics. You could use "single-column" and
> > "multi-column", but then "column" isn't really r
On Wed, Mar 24, 2021 at 05:15:46PM +, Dean Rasheed wrote:
> On Wed, 24 Mar 2021 at 16:48, Tomas Vondra
> wrote:
> >
> > As for the changes proposed in the create_statistics, do we really want
> > to use univariate / multivariate there? Yes, the terms are correct, but
> > I'm not sure how many
On Wed, 24 Mar 2021 at 16:48, Tomas Vondra
wrote:
>
> As for the changes proposed in the create_statistics, do we really want
> to use univariate / multivariate there? Yes, the terms are correct, but
> I'm not sure how many people looking at CREATE STATISTICS will
> understand them.
>
Hmm, I thin
On 3/24/21 5:28 PM, Dean Rasheed wrote:
> On Wed, 24 Mar 2021 at 14:48, Tomas Vondra
> wrote:
>>
>> AFAIK the primary issue here is that the two places disagree. While
>> estimate_num_groups does this
>>
>> varnos = pull_varnos(root, (Node *) varshere);
>> if (bms_membership(varnos) ==
On Wed, Mar 24, 2021 at 01:24:46AM -0500, Justin Pryzby wrote:
> It seems like you're preferring to use pluralized "statistics" in a lot of
> places that sound wrong to me. For example:
> > Currently the first statistics wins, which seems silly.
> I can write more separately, but I think this is r
On 3/24/21 7:24 AM, Justin Pryzby wrote:
> Most importantly, it looks like this forgets to update catalog documentation
> for stxexprs and stxkind='e'
>
Good catch.
> It seems like you're preferring to use pluralized "statistics" in a lot of
> places that sound wrong to me. For example:
>> Cu
On Wed, 24 Mar 2021 at 14:48, Tomas Vondra
wrote:
>
> AFAIK the primary issue here is that the two places disagree. While
> estimate_num_groups does this
>
> varnos = pull_varnos(root, (Node *) varshere);
> if (bms_membership(varnos) == BMS_SINGLETON)
> { ... }
>
> the add_unique_group
On 3/24/21 2:36 PM, Dean Rasheed wrote:
> On Wed, 24 Mar 2021 at 10:22, Tomas Vondra
> wrote:
>>
>> Thanks, it seems to be some thinko in handling in PlaceHolderVars, which
>> seem to break the code's assumptions about varnos. This fixes it for me,
>> but I need to look at it more closely.
>>
>
>
On Wed, 24 Mar 2021 at 10:22, Tomas Vondra
wrote:
>
> Thanks, it seems to be some thinko in handling in PlaceHolderVars, which
> seem to break the code's assumptions about varnos. This fixes it for me,
> but I need to look at it more closely.
>
I think that makes sense.
Reviewing the docs, I not
On Wed, Mar 24, 2021 at 09:54:22AM +0100, Tomas Vondra wrote:
> Hi Justin,
>
> Unfortunately the query is incomplete, so I can't quite determine what
> went wrong. Can you extract the full query causing the crash, either
> from the server log or from a core file?
Oh, shoot, I didn't realize it wa
Hi Justin,
Unfortunately the query is incomplete, so I can't quite determine what
went wrong. Can you extract the full query causing the crash, either
from the server log or from a core file?
thanks
On 3/24/21 9:14 AM, Justin Pryzby wrote:
> I got this crash running sqlsmith:
>
> #1 0x7f90
I got this crash running sqlsmith:
#1 0x7f907574b801 in __GI_abort () at abort.c:79
#2 0x5646b95a35f8 in ExceptionalCondition
(conditionName=conditionName@entry=0x5646b97411db "bms_num_members(varnos) ==
1", errorType=errorType@entry=0x5646b95fa00b "FailedAssertion",
fileName=file
Most importantly, it looks like this forgets to update catalog documentation
for stxexprs and stxkind='e'
It seems like you're preferring to use pluralized "statistics" in a lot of
places that sound wrong to me. For example:
> Currently the first statistics wins, which seems silly.
I can write mo
On Wed, 17 Mar 2021 at 21:31, Tomas Vondra
wrote:
>
> I agree applying at least the [(a+b),c] stats is probably the right
> approach, as it means we're considering at least the available
> information about dependence between the columns.
>
> I think to improve this, we'll need to teach the code t
On 3/17/21 9:58 PM, Dean Rasheed wrote:
> On Wed, 17 Mar 2021 at 20:48, Dean Rasheed wrote:
>>
>> For reference, here is the test case I was using (which isn't really very
>> good for
>> catching dependence between columns):
>>
>
> And here's a test case with much more dependence between the
On Wed, 17 Mar 2021 at 20:48, Dean Rasheed wrote:
>
> For reference, here is the test case I was using (which isn't really very
> good for
> catching dependence between columns):
>
And here's a test case with much more dependence between the columns:
DROP TABLE IF EXISTS foo;
CREATE TABLE foo (
On Wed, 17 Mar 2021 at 19:07, Tomas Vondra
wrote:
>
> On 3/17/21 7:54 PM, Dean Rasheed wrote:
> >
> > it might have been better to estimate the first case as
> >
> > ndistinct((a+b)) * ndistinct(c) * ndistinct(d)
> >
> > and the second case as
> >
> > ndistinct((a+b)) * ndistinct((c+d))
On 3/17/21 7:54 PM, Dean Rasheed wrote:
> On Wed, 17 Mar 2021 at 17:26, Tomas Vondra
> wrote:
>>
>> My concern is that the current behavior (where we prefer expression
>> stats over multi-column stats to some extent) works fine as long as the
>> parts are independent, but once there's dependenc
On Wed, 17 Mar 2021 at 17:26, Tomas Vondra
wrote:
>
> My concern is that the current behavior (where we prefer expression
> stats over multi-column stats to some extent) works fine as long as the
> parts are independent, but once there's dependency it's probably more
> likely to produce underestim
Hi,
On 3/17/21 4:55 PM, Dean Rasheed wrote:
> On Sun, 7 Mar 2021 at 21:10, Tomas Vondra
> wrote:
>>
>> 2) ndistinct
>>
>> There's one thing that's bugging me, in how we handle "partial" matches.
>> For each expression we track both the original expression and the Vars
>> we extract from it. If w
On Sun, 7 Mar 2021 at 21:10, Tomas Vondra wrote:
>
> 2) ndistinct
>
> There's one thing that's bugging me, in how we handle "partial" matches.
> For each expression we track both the original expression and the Vars
> we extract from it. If we can't find a statistics matching the whole
> expressio
On Thu, 4 Mar 2021 at 22:16, Tomas Vondra wrote:
>
> Attached is a slightly improved version of the patch series, addressing
> most of the issues raised in the previous message.
Cool. Sorry for the delay replying.
> 0003-Extended-statistics-on-expressions-20210304.patch
>
> Mostly unchanged, The
On 3/5/21 1:43 AM, Justin Pryzby wrote:
> On Mon, Jan 04, 2021 at 09:45:24AM -0600, Justin Pryzby wrote:
>> On Mon, Jan 04, 2021 at 03:34:08PM +, Dean Rasheed wrote:
>>> * I'm not sure I understand the need for 0001. Wasn't there an earlier
>>> version of this patch that just did it by re-popul
On Mon, Jan 04, 2021 at 09:45:24AM -0600, Justin Pryzby wrote:
> On Mon, Jan 04, 2021 at 03:34:08PM +, Dean Rasheed wrote:
> > * I'm not sure I understand the need for 0001. Wasn't there an earlier
> > version of this patch that just did it by re-populating the type
> > array, but which still h
On 1/27/21 12:02 PM, Dean Rasheed wrote:
> On Fri, 22 Jan 2021 at 03:49, Tomas Vondra
> wrote:
>>
>> Whooops. A fixed version attached.
>>
>
> The change to pg_stats_ext_exprs isn't quite right, because now it
> cross joins expressions and their stats, which leads to too many rows,
> with the
On 1/22/21 5:01 AM, Justin Pryzby wrote:
On Fri, Jan 22, 2021 at 04:49:51AM +0100, Tomas Vondra wrote:
| Statistics objects:
| "public"."s2" (ndistinct, dependencies, mcv) ON FROM t
Umm, for me that prints:
"public"."s2" ON ((i + 1)), (((i + 1) + 0)) FROM t
which I think is OK
On 1/22/21 10:00 AM, Dean Rasheed wrote:
On Fri, 22 Jan 2021 at 04:46, Justin Pryzby wrote:
I think you'll maybe have to do something better - this seems a bit too weird:
| postgres=# CREATE STATISTICS s2 ON (i+1) ,i FROM t;
| postgres=# \d t
| ...
| "public"."s2" (ndistinct, dependenc
On Fri, 22 Jan 2021 at 04:46, Justin Pryzby wrote:
>
> I think you'll maybe have to do something better - this seems a bit too weird:
>
> | postgres=# CREATE STATISTICS s2 ON (i+1) ,i FROM t;
> | postgres=# \d t
> | ...
> | "public"."s2" (ndistinct, dependencies, mcv) ON i FROM t
>
I guess th
On Thu, Jan 21, 2021 at 10:01:01PM -0600, Justin Pryzby wrote:
> On Fri, Jan 22, 2021 at 04:49:51AM +0100, Tomas Vondra wrote:
> > > > | Statistics objects:
> > > > | "public"."s2" (ndistinct, dependencies, mcv) ON FROM t
> >
> > Umm, for me that prints:
>
> > "public"."s2" ON ((i + 1)),
On Fri, Jan 22, 2021 at 04:49:51AM +0100, Tomas Vondra wrote:
> > > | Statistics objects:
> > > | "public"."s2" (ndistinct, dependencies, mcv) ON FROM t
>
> Umm, for me that prints:
> "public"."s2" ON ((i + 1)), (((i + 1) + 0)) FROM t
>
> which I think is OK. But maybe there's something
This already needs to be rebased on 55dc86eca.
And needs to update rules.out.
And doesn't address this one:
On Sun, Jan 17, 2021 at 10:53:31PM -0600, Justin Pryzby wrote:
> | postgres=# CREATE TABLE t(i int);
> | postgres=# CREATE STATISTICS s2 ON (i+1) ,(i+1+0) FROM t;
> | postgres=# \d t
> |
On Tue, 19 Jan 2021 at 01:57, Tomas Vondra
wrote:
>
> > A slightly bigger issue that I don't like is the way it assigns
> > attribute numbers for expressions starting from
> > MaxHeapAttributeNumber+1, so the first expression has an attnum of
> > 1601. That leads to pretty inefficient use of Bitma
On 1/18/21 4:48 PM, Dean Rasheed wrote:
Looking through extended_stats.c, I found a corner case that can lead
to a seg-fault:
CREATE TABLE foo();
CREATE STATISTICS s ON (1) FROM foo;
ANALYSE foo;
This crashes in lookup_var_attr_stats(), because it isn't expecting
nvacatts to be 0. I can't thi
Looking through extended_stats.c, I found a corner case that can lead
to a seg-fault:
CREATE TABLE foo();
CREATE STATISTICS s ON (1) FROM foo;
ANALYSE foo;
This crashes in lookup_var_attr_stats(), because it isn't expecting
nvacatts to be 0. I can't think of any case where building stats on a
tab
On Sun, Jan 17, 2021 at 01:23:39AM +0100, Tomas Vondra wrote:
> > CREATE TABLE t AS SELECT generate_series(1,9) AS i;
> > CREATE STATISTICS s ON (i+1) ,(i+1+0) FROM t;
> > ANALYZE t;
> > SELECT i+1 FROM t GROUP BY 1;
> > ERROR: corrupt MVNDistinct entry
>
> Thanks. There was a thinko in estimate_
On 1/17/21 6:29 AM, Justin Pryzby wrote:
On Sun, Jan 17, 2021 at 01:23:39AM +0100, Tomas Vondra wrote:
diff --git a/doc/src/sgml/ref/create_statistics.sgml
b/doc/src/sgml/ref/create_statistics.sgml
index 4363be50c3..5b8eb8d248 100644
--- a/doc/src/sgml/ref/create_statistics.sgml
+++ b/doc/sr
On 1/17/21 3:55 AM, Zhihong Yu wrote:
Hi,
+ * Check that only the base rel is mentioned. (This should be dead code
+ * now that add_missing_from is history.)
+ */
+ if (list_length(pstate->p_rtable) != 1)
If it is dead code, it can be removed, right ?
Maybe. The question is whe
On Sun, Jan 17, 2021 at 01:23:39AM +0100, Tomas Vondra wrote:
> diff --git a/doc/src/sgml/ref/create_statistics.sgml
> b/doc/src/sgml/ref/create_statistics.sgml
> index 4363be50c3..5b8eb8d248 100644
> --- a/doc/src/sgml/ref/create_statistics.sgml
> +++ b/doc/src/sgml/ref/create_statistics.sgml
> @
Hi,
+* Check that only the base rel is mentioned. (This should be dead code
+* now that add_missing_from is history.)
+*/
+ if (list_length(pstate->p_rtable) != 1)
If it is dead code, it can be removed, right ?
For statext_mcv_clauselist_selectivity:
+ // bms_fre
On Sat, Jan 16, 2021 at 05:48:43PM +0100, Tomas Vondra wrote:
> +
> + expr text
> +
> +
> + Expression the extended statistics is defined on
> +
Expression the extended statistics ARE defined on
Or maybe say "on which the extended statistics are defined"
> +
On 1/8/21 3:35 AM, Justin Pryzby wrote:
> On Fri, Jan 08, 2021 at 01:57:29AM +0100, Tomas Vondra wrote:
>> Attached is a patch fixing most of the issues. There are a couple
>> exceptions:
>
> In the docs:
>
> ...
>
Thanks! Checking the docs and comments is a tedious work, I appreciate
you going
On Fri, Jan 08, 2021 at 01:57:29AM +0100, Tomas Vondra wrote:
> Attached is a patch fixing most of the issues. There are a couple
> exceptions:
In the docs:
+ — at the cost that its schema must be extended whenever the structure
Starting to look at the planner code, I found an oversight in the way
expression stats are read at the start of planning -- it is necessary
to call ChangeVarNodes() on any expressions if the relid isn't 1,
otherwise the stats expressions may contain Var nodes referring to the
wrong relation. Possib
Looking over the statscmds.c changes, there are a few XXX's and
FIXME's that need resolving, and I had a couple of other minor
comments:
+ /*
+* An expression using mutable functions is probably wrong,
+* since if you aren't going to get the same result for the
+
On 1/5/21 3:10 PM, Dean Rasheed wrote:
On Tue, 5 Jan 2021 at 00:45, Tomas Vondra wrote:
On 1/4/21 4:34 PM, Dean Rasheed wrote:
* In src/bin/psql/describe.c, I think the \d output should also
exclude the "expressions" stats kind and just list the other kinds (or
have no kinds list at all,
On Tue, 5 Jan 2021 at 00:45, Tomas Vondra wrote:
>
> On 1/4/21 4:34 PM, Dean Rasheed wrote:
> >
> > * In src/bin/psql/describe.c, I think the \d output should also
> > exclude the "expressions" stats kind and just list the other kinds (or
> > have no kinds list at all, if there are no other kinds)
On 1/4/21 4:34 PM, Dean Rasheed wrote:
...
Some other comments:
* I'm not sure I understand the need for 0001. Wasn't there an earlier
version of this patch that just did it by re-populating the type
array, but which still had it as an array rather than turning it into
a list? Making it a li
On Mon, Jan 04, 2021 at 03:34:08PM +, Dean Rasheed wrote:
> * I'm not sure I understand the need for 0001. Wasn't there an earlier
> version of this patch that just did it by re-populating the type
> array, but which still had it as an array rather than turning it into
> a list? Making it a lis
On Fri, 11 Dec 2020 at 20:17, Tomas Vondra
wrote:
>
> OK. Attached is an updated version, reworking it this way.
Cool. I think this is an exciting development, so I hope it makes it
into the next release.
I have started looking at it. So far I have only looked at the
catalog, parser and client c
On Tue, 8 Dec 2020 at 12:44, Tomas Vondra wrote:
>
> Possibly. But I don't think it's worth the extra complexity. I don't
> expect people to have a lot of overlapping stats, so the amount of
> wasted space and CPU time is expected to be fairly limited.
>
> So I don't think it's worth spending too
On 12/7/20 5:02 PM, Dean Rasheed wrote:
> On Mon, 7 Dec 2020 at 14:15, Tomas Vondra
> wrote:
>>
>> On 12/7/20 10:56 AM, Dean Rasheed wrote:
>>> it might actually be
>>> neater to have separate documented syntaxes for single- and
>>> multi-column statistics:
>>>
>>> CREATE STATISTICS [ IF NOT
On Mon, 7 Dec 2020 at 14:15, Tomas Vondra wrote:
>
> On 12/7/20 10:56 AM, Dean Rasheed wrote:
> > it might actually be
> > neater to have separate documented syntaxes for single- and
> > multi-column statistics:
> >
> > CREATE STATISTICS [ IF NOT EXISTS ] statistics_name
> > ON (expression)
On 12/7/20 10:56 AM, Dean Rasheed wrote:
> On Thu, 3 Dec 2020 at 15:23, Tomas Vondra
> wrote:
>>
>> Attached is a patch series rebased on top of 25a9e54d2d.
>
> After reading this thread and [1], I think I prefer the name
> "standard" rather than "expressions", because it is meant to describe
On Thu, 3 Dec 2020 at 15:23, Tomas Vondra wrote:
>
> Attached is a patch series rebased on top of 25a9e54d2d.
After reading this thread and [1], I think I prefer the name
"standard" rather than "expressions", because it is meant to describe
the kind of statistics being built rather than what they
On 11/24/20 5:23 PM, Justin Pryzby wrote:
> On Mon, Nov 23, 2020 at 04:30:26AM +0100, Tomas Vondra wrote:
>> 0004 - Seems fine. IMHO not really "silly errors" but OK.
>
> This is one of the same issues you pointed out - shadowing a variable.
> Could be backpatched.
>
> On Mon, Nov 23, 2020 at
On Mon, Nov 23, 2020 at 04:30:26AM +0100, Tomas Vondra wrote:
> 0004 - Seems fine. IMHO not really "silly errors" but OK.
This is one of the same issues you pointed out - shadowing a variable.
Could be backpatched.
On Mon, Nov 23, 2020 at 04:30:26AM +0100, Tomas Vondra wrote:
> > +
On 11/23/20 3:26 AM, Justin Pryzby wrote:
> On Sun, Nov 22, 2020 at 08:03:51PM +0100, Tomas Vondra wrote:
>> attached is a significantly improved version of the patch, allowing
>> defining extended statistics on expressions. This fixes most of the
>> problems in the previous WIP version and AFAI
On 11/16/20 2:49 PM, Tomas Vondra wrote:
> Hi,
>
> ...
>
> 4) apply the statistics
>
>This is the hard part, really, and the exact state of the support
>depends on type of statistics.
>
>For ndistinct coefficients, it generally works. I'm sure there may be
>bugs in estimate_num_gr
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