On 08/05/2019 01:31, Heikki Linnakangas wrote:
> On 02/05/2019 10:37, Heikki Linnakangas wrote:
>> On 29/04/2019 16:16, Anastasia Lubennikova wrote:
>>> In previous emails, I have sent two patches with test and bugfix (see
>>> attached).
>>> After Heikki shared his concerns, I've rechecked the algorithm and
>>> haven't found any potential error.
>>> So, if other hackers are agreed with my reasoning, the suggested fix is
>>> sufficient and can be committed.
>>
>> I still believe there is a problem with grandparent splits with this.
>> I'll try to construct a test case later this week, unless you manage to
>> create one before that.
>
> Here you go. If you apply the two patches from
> https://www.postgresql.org/message-id/5d48ce28-34cf-9b03-5d42-dbd5457926bf%40postgrespro.ru,
> and run the attached script, it will print out something like this:
>
> postgres=# \i grandparent.sql
> DROP TABLE
> CREATE TABLE
> INSERT 0 150000
> CREATE INDEX
> psql:grandparent.sql:27: NOTICE: working on 10000
> psql:grandparent.sql:27: NOTICE: working on 20000
> psql:grandparent.sql:27: NOTICE: working on 30000
> psql:grandparent.sql:27: NOTICE: working on 40000
> psql:grandparent.sql:27: NOTICE: working on 50000
> psql:grandparent.sql:27: NOTICE: working on 60000
> psql:grandparent.sql:27: NOTICE: working on 70000
> psql:grandparent.sql:27: NOTICE: working on 80000
> psql:grandparent.sql:27: NOTICE: working on 90000
> psql:grandparent.sql:27: NOTICE: working on 100000
> psql:grandparent.sql:27: NOTICE: working on 110000
> psql:grandparent.sql:27: NOTICE: failed for 114034
> psql:grandparent.sql:27: NOTICE: working on 120000
> DO
>
> That "failed for 114034" should not happen.
>
> Fortunately, that's not too hard to fix. We just need to arrange things
> so that the "retry_from_parent" flag also gets set for the grandparent,
> when the grandparent is split. Like in the attached patch.
I hear no objections, so pushed that. But if you have a chance to review
this later, just to double-check, I'd still appreciate that.
- Heikki
