Re: Performance regression since 3.19.0

Hi -- I've not heard anything more about this, and I don't see a bug listed
at https://www.sqlite.org/src/rptview?rn=1.

Will it be addressed as a bug?

I hope I'm not coming across as demanding a fix -- I just want to make sure
this hasn't fallen through the gaps!

On Mon, 6 Jan 2020 at 20:24, Peter Inglesby <[email protected]>
wrote:

>
> How does the performance compare with this:
>>
>> CREATE TABLE t1 (a TEXT, b TEXT);
>> CREATE TABLE t2 (a TEXT, b TEXT);
>> CREATE INDEX t1_a ON t1 (a,b);
>> CREATE INDEX t2_a ON t2 (a,b);
>>
>> SELECT *
>> FROM t1 LEFT JOIN t2 ON (t1.b=t2.b AND t2.a='123')
>> WHERE t1.a='123';
>>
>
> Here are best-of-three averages for my version and your version for both
> the good and bad commits:
>
> good / mine :: <0.1s
> bad / mine :: 12.5s
> good / yours :: 0.2s
> bad / yours :: 0.2s
>
> In other words, there is no regression for your version.  But it does not
> return as quickly as my version does before the regression.
>
>
>> Run "ANALYZE;" on a database that contains actual data, then send us
>> the output of ".fullschema"
>>
>
> Here you go:
>
> sqlite> analyze;
> sqlite> .fullschema
> CREATE TABLE t1 (a TEXT, b TEXT);
> CREATE TABLE t2 (a TEXT, b TEXT);
> CREATE INDEX t1_a ON t1 (a);
> CREATE INDEX t1_b ON t1 (b);
> CREATE INDEX t2_a ON t2 (a);
> CREATE INDEX t2_b ON t2 (b);
> ANALYZE sqlite_master;
> ANALYZE sqlite_master;
> INSERT INTO sqlite_stat1 VALUES('t2','t2_b','1000000 1000');
> INSERT INTO sqlite_stat1 VALUES('t2','t2_a','1000000 1000');
> INSERT INTO sqlite_stat1 VALUES('t1','t1_b','1000000 1000');
> INSERT INTO sqlite_stat1 VALUES('t1','t1_a','1000000 1000');
> ANALYZE sqlite_master;
>
> The sqlite_stat1 values make sense, because there are 1,000,000 rows in
> each of t1 and t2, with 1,000 values for each of a and b.
>
> After running ANALYZE, the origin query returns in 2.7s, but the query
> plan is unchanged.
>
> On Mon, 6 Jan 2020 at 01:53, Richard Hipp <[email protected]> wrote:
>
>> How does the performance compare with this:
>>
>> CREATE TABLE t1 (a TEXT, b TEXT);
>> CREATE TABLE t2 (a TEXT, b TEXT);
>> CREATE INDEX t1_a ON t1 (a,b);
>> CREATE INDEX t2_a ON t2 (a,b);
>>
>> SELECT *
>> FROM t1 LEFT JOIN t2 ON (t1.b=t2.b AND t2.a='123')
>> WHERE t1.a='123';
>>
>>
>> On 1/5/20, Peter Inglesby <[email protected]> wrote:
>> > Is there any more information I could provide?
>>
>> Run "ANALYZE;" on a database that contains actual data, then send us
>> the output of ".fullschema"
>>
>> --
>> D. Richard Hipp
>> [email protected]
>> _______________________________________________
>> sqlite-users mailing list
>> [email protected]
>> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
>>
>
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