How to config hibernate isolation level for postgres - postgresql

Question

I have a table ErrorCase in postgres database. This table has one field case_id with datatype text. Its value is generated by format: yymmdd_xxxx. yymmdd is the date when the record insert to DB, xxxx is the number of record in that date.
For example, 3th error case on 2019/08/01 will have the case_id = 190801_0003. On 08/04, if there is one more case, its case_id will be 190804_0001, and go on.
I already using trigger in database to generate value for this field:
DECLARE
total integer;
BEGIN
SELECT (COUNT(*) + 1) INTO total FROM public.ErrorCase WHERE create_at = current_date;
IF (NEW.case_id is null) THEN
NEW.case_id = to_char(current_timestamp, 'YYMMDD_') || trim(to_char(total, '0000'));
END IF;
RETURN NEW;
END
And in Spring Project, I config the application properties for jpa/hibernates:
datasource:
type: com.zaxxer.hikari.HikariDataSource
url: jdbc:postgresql://localhost:5432/table_name
username: postgres
password: postgres
hikari:
poolName: Hikari
auto-commit: false
jpa:
database-platform: io.github.jhipster.domain.util.FixedPostgreSQL82Dialect
database: POSTGRESQL
show-sql: true
properties:
hibernate.id.new_generator_mappings: true
hibernate.connection.provider_disables_autocommit: true
hibernate.cache.use_second_level_cache: true
hibernate.cache.use_query_cache: false
hibernate.generate_statistics: true
Currently, it generates the case_id correctly.
However, when insert many records in nearly same time, it generates the same case_id for two record. I guess the reason is because of the isolation level. When the first transaction not yet committed, the second transaction do the SELECT query to build case_id. So, the result of SELECT query does not include the record from first query (because it has not committed yet). Therefore, the second case_id has the same result as the first one.
Please suggest me any solution for this problems, which isolation level is good for this case???

Answer 1

"yymmdd is the date when the record insert to DB, xxxx is the number of record in that date" - no offense but that is a horrible design.
You should have two separate columns, one date column and one integer column. If you want to increment the counter during an insert, make that date column the primary key and use insert on conflict. You can get rid that horribly inefficient trigger and more importantly that will be safe for concurrent modifications even with read committed.
Something like:
create table error_case
(
error_date date not null primary key,
counter integer not null default 1
);
Then use the following to insert rows:
insert into error_case (error_date)
values (date '2019-08-01')
on conflict (error_date) do update
set counter = counter + 1;
No trigger needed and safe for concurrent inserts.
If you really need a text column as a "case ID", create a view that returns that format:
create view v_error_case
as
select concat(to_char(error_date, 'yymmdd'), '_', to_char(counter, '0000')) as case_id,
... other columns
from error_case;