On Sat, Sep 21, 2019 at 10:17 PM Fredrik Larsen wrote:
> [...] But fixing issues in less than a day of reporting? [...]
>
That's not unusual at all for SQLite. Either it gets "fixed" quickly, or it
doesn't.
The hard part is making the case with Richard (and Dan) about the merit of
the
change,
Good to know that I was not to far off target then. But fixing issues in
less than a day of reporting? On a Saturday? Who does that? I was planning
to feel happy about solving this issue.. :)
Fredrik
On Sat, Sep 21, 2019 at 9:31 PM Dan Kennedy wrote:
>
> On 22/9/62 02:25, Fredrik Larsen wrote:
On 22/9/62 02:25, Fredrik Larsen wrote:
Interesting, very similar change but not fully idenctial. In my patch, I
created a sqlite3ExprListCompareIgnoreButUpdateSort, and used this function
from line 6239. This function ignores the sort part when comparing
expressions, but will update the
Interesting, very similar change but not fully idenctial. In my patch, I
created a sqlite3ExprListCompareIgnoreButUpdateSort, and used this function
from line 6239. This function ignores the sort part when comparing
expressions, but will update the GroupBy sortOrder field if expressions are
found
See Dan's checkin on trunk for this issue.
https://www.sqlite.org/src/info/20f7951bb238ddc0
>-Original Message-
>From: sqlite-users On
>Behalf Of Fredrik Larsen
>Sent: Saturday, 21 September, 2019 08:12
>To: SQLite mailing list
>Subject: Re: [sqlite] [EXTERNAL] Group-by and
To clarify; GROUP-BY does not really have ordering, but in the SQLite
implementation, GROUP-BY and ORDER-BY is very closely related as expected,
and it is possible to set a GROUP-BY direction in code (it is default 0 ->
ASC). So thats what I did. Also, some other modifications very required to
Your last sentence got me thinking. So I downloaded the source, modified
the ordering of the GROUP-BY expression to match ORDER-BY and it works!
This will offcourse only work if the GROUP-BY and ORDER-BY matches
generally expect for the direction. This fix only improves performance for
relevant
>We can observe GROUP BY works ASCending only as of now. Why it can't work
>DESCending to avoid ordering, that's a different question.
>From https://www.sqlite.org/lang_select.html we can observe that
>GROUP BY takes an expr on the RHS, while ORDER BY takes an expr
>followed by optional COLLATE
I´m not sure why you think group_by + order_by_desc + limit N queries are
so obscure? Useful for lots of tail-statistics (number of transactions last
N hours if group_key is time-based, etc).
In my case I'm implementing a event-store using sqlite, where I need to be
able to retrieve entity data
On 2019/09/20 2:49 PM, Fredrik Larsen wrote:
Hi Ryan
Nobody is proposing that QP should automagically add an index, I'm only
asking why the QP does not use already added index, that is specially added
for this specific case. I don't thinks this is a very "obscurest of
use-case" or to much to
Hi Ryan
Nobody is proposing that QP should automagically add an index, I'm only
asking why the QP does not use already added index, that is specially added
for this specific case. I don't thinks this is a very "obscurest of
use-case" or to much to ask for, in fact, this is the expected behavior
On 2019/09/20 11:12 AM, Dominique Devienne wrote:
But who says the GROUP BY must return rows in ASCending order?
A lot of us "oldies" of this ML well know the order is arbitrary and
subject to change w/o an explicit ORDER BY.
So the GROUP BY is allowed, AFAIK, to return rows in DESCending
On Fri, Sep 20, 2019 at 12:33 PM Hick Gunter wrote:
> The dialogue from the stackoverflow discussion shows this quite clearly.
>
Shows what clearly Gunter? I'm not sure to follow. I've read the SO post,
and I don't get your point.
We can observe GROUP BY works ASCending only as of now. Why it
The dialogue from the stackoverflow discussion shows this quite clearly.
"The code for looping over an index goes backwards only when needed. For
implementing GROUP BY itself, going backwards is never needed, so it is never
tried.
It is possible that a future SQLite version might add code to
On Thu, Sep 19, 2019 at 6:15 PM Hick Gunter wrote:
> -Ursprüngliche Nachricht-
> Von: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org]
> Im Auftrag von Fredrik Larsen
> Gesendet: Donnerstag, 19. September 2019 17:29
> An: SQLite mailing list
> Betreff: Re: [sqlite]
-Ursprüngliche Nachricht-
Von: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org] Im
Auftrag von Fredrik Larsen
Gesendet: Donnerstag, 19. September 2019 17:29
An: SQLite mailing list
Betreff: Re: [sqlite] [EXTERNAL] Group-by and order-by-desc does not work as
expected
Simen; ANALYZE and PRAGMA reverse_unordered_selects = YES does not affect
results.
Hick; ORDER BY x DESC >is< covered by index. Btree-indexes allows traversal
both ways. You can see this if you remove GROUP_BY.
Got an answer on StackOverflow that seems to be from somebody that knows
internal
An ORDER BY clause will omit sorting only if the visitation order exactly
fulfills the clause.
A GROUP BY clause is able to avoid creating a temporary table if the visitation
order exactly fulfills the clause.
If a SELECT references only fields present in an index, that (covering) index
may
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