Re: Hibernate, web application and only one sequence for all primary keys - Mailing list pgsql-sql

From rawi
Subject Re: Hibernate, web application and only one sequence for all primary keys
Date
Msg-id 25491924.post@talk.nabble.com
Whole thread Raw
In response to Re: Hibernate, web application and only one sequence for all primary keys  (Leo Mannhart <leo.mannhart@beecom.ch>)
Responses Re: Hibernate, web application and only one sequence for all primary keys  (Rob Sargent <robjsargent@gmail.com>)
Re: Hibernate, web application and only one sequence for all primary keys  (Leo Mannhart <leo.mannhart@beecom.ch>)
Re: Hibernate, web application and only one sequence for all primary keys  (Kenneth Marshall <ktm@rice.edu>)
List pgsql-sql

Leo Mannhart wrote:
> 
> Caveat: If you use the standard sequence generator in hibernate, it is
> not using the postgres-sequence in the "usual" manner. hibernate itself
> caches 50 ID's as sequence numbers by default. This means, hibernate
> only does a select on the database sequence every 50 numbers. it
> multyplies the database sequence by 50 to get the "real" sequence
> number. it generates the sequence numbers in blocks of 50 numbers or
> according to the sequence cache size.
> That said, you would probably not see any performance bottlenecks
> because of the sequence number generator in the database, even with
> thousands of inserts per second.
> 

Hi Leo, thank you for the explanation!

I don't know if it is that cool to lose up to 50 IDs on each session-end of
Hibernate...
And what do you suppose it would happen, if I set the cache size of
Hibernate's own sequence (after generation) by hand to 1 instead of 50? I
wouldn't need tausends of inserts per second...

Kind regards, Rawi

-- 
View this message in context:
http://www.nabble.com/Hibernate%2C-web-application-and-only-one-sequence-for-all-primary-keys-tp25490498p25491924.html
Sent from the PostgreSQL - sql mailing list archive at Nabble.com.



pgsql-sql by date:

Previous
From: rawi
Date:
Subject: Re: Hibernate, web application and only one sequence for all primary keys
Next
From: rawi
Date:
Subject: Re: Hibernate, web application and only one sequence for all primary keys