Re: Partition boundary messed up

If you were thinking of some ALTER command which will just alter the
boundaries of the incorrect partition and make it correct , I don't think
there exists any such. You may have to create a whole new table and run the
partman.create_parent block with the UTC time zone set so that all the
subsequent partitions will be created with correct boundaries and then move
the data into it from the existing table.

On Thu, Jul 25, 2024 at 12:55 AM Lok P <loknath(dot)73(at)gmail(dot)com> wrote:

> Hello All,
> We normally operate on UTC timezone so we normally create partitions in
> UTC timezone so that each day partition starts from today's midnight UTC to
> next day's midnight UTC. The script looks something like below. And also
> that way reference partition tables are also created in a similar way. Say
> for example the 29th august partition in parent partition reference to 29th
> august child partition as FK. This was working fine even for partition
> maintenance(mainly while dropping historical partitions) too without any
> issue.
>
> For one of the newly introduced partition tables, by mistake somebody
> created the initial partition definition without setting the timezone to
> UTC and all the partitions created are in different time zones. And as this
> table refers to another partition table (which is the parent and have
> partitions created in UTC timezone) the rows are spanning across two
> partitions and it's breaking the partition maintenance process while we try
> to drop the historical partition.
>
> Now the issue is that the newly introduced table already has billions of
> rows pumped into it spanning across 40 partitions. So is there an easy way
> to just alter the partition boundary to make it UTC midnight to midnight
> range?
> or
> The only way is to create a new table from scratch with the correct
> partition boundary in UTC timezone and then move the data and then create
> foreign key on that(which I believe is going to take a lot of time too)?
>
> Another thing we noticed, it shows initial partitions having boundaries in
> NON UTC (which we understand because of the missing timezone syntax) but
> then suddenly the subsequent partitions are getting created UTC too, not
> sure how it happened. And I believe it will create issues while rows come
> into the database which falls in between these ranges? Wondering if there
> is any easy way to correct this mess now? Note- This is postgres version
> 15+.
>
> Below partition creation script we use:-
> set timesozne='UTC';
> SELECT partman.create_parent(
> p_parent_table := 'schema1.tab1',
> p_control := 'TRAN_DATE',
> p_type := 'native',
> p_interval := '1 day',
> p_premake := 90,
> p_start_partition => '2024-02-15 00:00:00'
> );
> UPDATE partman.part_config SET infinite_time_partitions = 'true' ,
> premake=20 WHERE parent_table = 'schema1.tab1';
> CALL partman.run_maintenance_proc();
>
> Below details i fetched from pg_class for the table which is messed up:-
>
> Partition_name Partition Expressions
> TAB1_p2024_08_29 FOR VALUES FROM ('2024-08-29 00:00:00+05:30') TO
> ('2024-08-30 00:00:00+05:30')
> TAB1_p2024_08_30 FOR VALUES FROM ('2024-08-30 00:00:00+05:30') TO
> ('2024-08-31 00:00:00+05:30')
> TAB1_p2024_08_31 FOR VALUES FROM ('2024-08-31 00:00:00+05:30') TO
> ('2024-09-01 00:00:00+05:30')
> TAB1_p2024_09_01 FOR VALUES FROM ('2024-09-01 00:00:00+05:30') TO
> ('2024-09-02 00:00:00+05:30')
>
> *TAB1_p2024_09_02 FOR VALUES FROM ('2024-09-02 00:00:00+05:30') TO
> ('2024-09-03 00:00:00+05:30')*
> *TAB1_p2024_09_03 FOR VALUES FROM ('2024-09-03 05:30:00+05:30') TO
> ('2024-09-04 05:30:00+05:30')*TAB1_p2024_09_04 FOR VALUES FROM
> ('2024-09-04 05:30:00+05:30') TO ('2024-09-05 05:30:00+05:30')
> TAB1_p2024_09_05 FOR VALUES FROM ('2024-09-05 05:30:00+05:30') TO
> ('2024-09-06 05:30:00+05:30')
> TAB1_p2024_09_06 FOR VALUES FROM ('2024-09-06 05:30:00+05:30') TO
> ('2024-09-07 05:30:00+05:30')
>
> Regards
> Lok
>