How to execute DDL and DML statements concurrently?

[Yifan <he...@msn.com>]

Recently my colleague has run some benchmark tests on Derby.

During the test we execute DDL and DML statements concurrently,

We find that Derby will lock the data dictionary for a relative long time
when executes DDL statements, 

and then the DML statements would not be executed and finally timed out.

Are there some way that we can work around this so that DDL and DML
statements can be executed concurrently?

 

Any help would be appreciated.

 

Thanks!

Yifan

Re: How to execute DDL and DML statements concurrently?

[Bryan Pendleton <bp...@amberpoint.com>]

> Do you mean we change the concurrency level in derby dynamically depending
> on the statements?

No, I was just wondering whether some DDL statements
locked out the DML statements longer than others did.

thanks,

bryan

re: How to execute DDL and DML statements concurrently?

[Yifan Wang <he...@gmail.com>]

The DDL statements are mostly “create” new tables.
In the test, it seems that the problems are not depending on different DDL
statements.

Do you mean we change the concurrency level in derby dynamically depending
on the statements?

Thanks
Yifan

-----邮件原件-----
发件人: Bryan Pendleton [mailto:bpendleton@amberpoint.com] 
发送时间: 2007年4月19日 22:34
收件人: derby-dev@db.apache.org
主题: Re: How to execute DDL and DML statements concurrently?

> We find that Derby will lock the data dictionary for a relative long 
> time when executes DDL statements,

Does it vary based on the DDL statement? Which DDL statements have you
tried, and can you measure differing concurrency levels depending on
the statement?

thanks,

bryan

Re: How to execute DDL and DML statements concurrently?

[Bryan Pendleton <bp...@amberpoint.com>]

> We find that Derby will lock the data dictionary for a relative long 
> time when executes DDL statements,

Does it vary based on the DDL statement? Which DDL statements have you
tried, and can you measure differing concurrency levels depending on
the statement?

thanks,

bryan