I would like to have a table with deleted column containing the date the item was soft-deleted. Rows with NULL value in deleted column are the active ones. I was not able to figure our the syntax to create a partition for null values in deleted column. What is the syntax of creating such column?
create table my_table_pointing(street_id int, p_city_id int, name varchar(10), deleted date)
PARTITION BY RANGE (deleted);
CREATE TABLE my_table_pointing_2020 PARTITION OF my_table_pointing
FOR VALUES FROM ('2020-01-01') TO ('2021-01-01');
CREATE TABLE my_table_pointing_active PARTITION OF my_table_pointing
"for all rows where date is null"...
Thanks!
Provided you are on PG11 or later, you can create a default partition, and rows with deleted is null will be routed there.
create table my_table_pointing_active partition of my_table_pointing default;
Related
So basically we have a very large table in Postgres 11 DB which has hundreds of millions of data since the table was added. Now we are trying to convert it into a range based partition table based on created_at column (timestamp - not nullable).
As suggested in the Postgres Partitioning Documentation, I tried adding a check constraint on the same table before actually running the attach partition. So after that if I run attach partition, ideally it should have taken very less time as it should skip the validation due to presence of respective constraint on the table, but I see it is still taking lot more time. My partition range and the constraint looks something like this:
alter table xyz_2020 add constraint temp_check check (created_at >= '2020-01-01 00:00:00' and created_at < '2021-01-01 00:00:00');
ALTER TABLE xyz ATTACH PARTITION xyz_2020 FOR VALUES FROM ('2020-01-01 00:00:00') TO ('2021-01-01 00:00:00');
Here xyz_2020 is my existing big table which got renamed from xyz. And xyz is the new master table created like the old table. So I want to understand what could be the possible reasons that attach partition might still be taking lot more time.
Edit: We are creating a new partitioned table and trying to attach the old table as one of its partition.
is it ok to rename a parent table from which partitioned child tables are based ?
For example if I have
CREATE TABLE demos_qa (
demo_id int,
demo_date VARCHAR,
demo_text TEXT)
PARTITION BY RANGE (trxn_post_dt);
CREATE TABLE demos_2022 PARTITION OF demos_qa
FOR VALUES FROM ('2022-01-01') TO ('2023-01-01');
CREATE TABLE demos_2021 PARTITION OF demos_qa
FOR VALUES FROM ('2021-01-01') TO ('2022-01-01');
CREATE TABLE demos_2020 PARTITION OF demos_qa
FOR VALUES FROM ('2020-01-01') TO ('2021-01-01');
and I bulk load the partition tables.
I now want to rename the parent table from demo_qa to demo. Can I do that and will things work as normal without having to change the definitions of the partition tables ?
Yes, this will work.
The partitions won't be renamed though, in case you expected that.
I have a table that is partitioned by hash on a column.
CREATE TABLE TEST(
ACCOUNT_NUMBER VARCHAR(20)
)
PARTITION BY HASH (ACCOUNT_NUMBER)
PARTITIONS 16
Now, I want to update the account_number column itself in the table because of certain requirements.
As this column is partitioned, I'm not able to issue an update command on the table like
Update test set account_number = new_value
as it results to the below error:
Error is: ORA-14402: UPDATING PARTITION WOULD CAUSE PARTITION CHANGE.
Row movement is set to disable for the table.
The one way I know is to enable row movement but I also want to explore other options.
Could you please advise me on how to solve this?
I have a table partitioned by range in Postgres 10.6. Is there a way to tell one of its partitions to accept NULL for the column used as partition key?
The reason I need this is: my table size is 200GB and it's actually not yet partitioned. I want to partition it going forward, so I thought I would create an initial partition including all of the current rows, and then at the start of each month I would create another partition for that month's data.
The issue is, currently this table doesn't have the column I'll use for partitioning, so I want to add the column (initially null) and then tell that initial partition to hold all rows that have null in the partitioning key.
Another option would be to not add the column as null but to set an initial date value, but that would be time and space consuming because of the size of that table.
I would upgrade to v11 and initially define the partitioned table with just a default partition that contains all the NULL values.
Then you can add other partitions and gradually move the data by updating the NULL values.
I want to split up a table into partitions, where I have a partition for each distinct value of a column. So, if foo_id is the column, I want to put a row with foo_id=23 into the partition bar_23. Is it possible to then remove the column from the partitions and still use the value for selecting the partition via constraints or do I have to explicitly name the partition table in the query?
I.e., can I do this
INSERT INTO bar (foo_id, other) (23, 'value');
without actually having foo_id in the table? Or do I have to go the explicit way:
INSERT INTO bar_23 (other) ('value');