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From Daniel John Debrunner <...@debrunners.com>
Subject Re: [jira] Commented: (DERBY-464) Enhance Derby by adding grant/revoke support. Grant/Revoke provide finner level of privileges than currently provided by Derby that is especially useful in network configurations.
Date Tue, 27 Dec 2005 16:50:03 GMT
Satheesh Bandaram wrote:
> Some answers below....
> 
> Daniel John Debrunner (JIRA) wrote:
> 
>>    [ http://issues.apache.org/jira/browse/DERBY-464?page=comments#action_12361221
] 
>>
>>spec> DDL statements directly invoke executing mechanism simplify the implementation
at the cost of a small increase in execution time.
>>
>>I don't think that's true. DDL''s are not slower due to using a constant action. That's
not the reason for the way they are handled. I think the basic idea is that DDL's are limited
in structure compared to DML and can easily be represented by an object that represents an
action and a set of constants. DDL did  generate a java class to execute the constant action
but I cleaned that up to use a fixed implementation (sub-class) of BaseActivation , as otherwise
each DDL would be generating an identical class. This was wasteful when most DDL is discarded
after a single execution.
>>  
>>
> One side-effect of directly executing DDLs is that they need to be
> compiled everytime... I think that is what I was refering to.. though I
> don't see many useful cases where sharing a DDL plan would be useful. I
> will modify the line.

I don't think that's the case. DDL statements are cached like any other
statement. The exact same mechanism is used to exeucte constant action
statements as other statements.

Dan.


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