Re: [Springframework-developer] I would like to remove JdbcTemplate/JdbcAccessor eager init of exception translator

[Colin S. <col...@ex...>]

Well, it's quite easy to make it configurable (in the fashion I 
mentioned below). However, somebody putting it in the context, where 
it's easy to configure, would probably not even care about the eager 
init, since they'll be using it as a singleton. On the other hand, 
somebody using 'new JdbcTemplate(datasource, eagerInitFlag), who would 
benefit from not doing the eager init unless absolutely necessary, since 
they are using non-singleton instances, probably has no easy way to 
configure that value. The whole point was to not have to pass both a 
datasource and jdbctemplate to various component, but only a datasource. 
If an eager init config flag is passed, then the jdbctemplate can just 
as readily be passed.

There are probably still a few edge cases where the flag would be useful 
though...

Regards,
Colin

tri...@tr... wrote:

>Maybe we could make lazy init it configurable with the default beeing eager
>init.  I'll give it some thouhgt this week - maybe we can squeeze it in before RC2.
>
>Thomas
>
>Quoting Colin Sampaleanu <col...@ex...>:
>
>  
>
>>Hmm, too bad.   The problem is that if you can get your hands on the 
>>database name, which is something that you would never want to hard-code 
>>in your code, then you can probably also just get your hands on a 
>>jdbcTemplate instance from the context, used as a singleton.   I was 
>>hoping to just make 'new jdbcTemplate(datasource)' as efficient as that 
>>approach...
>>
>>
>>tri...@tr... wrote:
>>
>>    
>>
>>>Colin,
>>>
>>>I think Rod did make it lazy init at some point, but the problem was that
>>>      
>>>
>>some
>>    
>>
>>>jdbc driver (I think MS SQL Server) was not letting us use the connection
>>>      
>>>
>>after
>>    
>>
>>>some exception was thrown.  This prevented us from loading the meta data and
>>>      
>>>
>>the
>>    
>>
>>>translation mapping.  
>>>
>>>All we really need is the database product name, so if you
>>>could set that explicitly, then we don't need to look it up.  
>>>
>>>There is already code in SQLErrorCodesFactory to avoid the database
>>>      
>>>
>>metadata
>>    
>>
>>>lookup if you pass in a database product name.
>>>
>>> public SQLErrorCodes getErrorCodes(String dbName)
>>>
>>>I think all you need now is to do is create a custom 
>>>SQLErrorCodeSQLExceptionTranslator where you set the database product name
>>>explicitly and load the error codes using this rather than the data source.
>>>
>>>Thomas
>>>
>>>
>>>
>>>Quoting Colin Sampaleanu <col...@ex...>:
>>>
>>> 
>>>
>>>      
>>>
>>>>I've been sitting here all day watching logs go by as I try to get a 
>>>>system into production, and seeing a lot of pauses as the
>>>> new JdbcTemplate(dataSource)
>>>>in JdbcHelper causes, every single time JdbcHelper is created, the 
>>>>exception metadata to be pulled from the DB.
>>>>
>>>>Now this is code using Spring slightly post RC1. I realize JdbcHelper 
>>>>has gone away, but the same thing happens of course when you just do a 
>>>>'new JdbcTemplate(dataSource)' directly.
>>>>
>>>>I don't know why JdbcAccessor (and hence JdbcTemplate) really needs to 
>>>>eager init the exception translator. The access method is synchronized, 
>>>>so there should be no issues letting it lazy init.
>>>>
>>>>I would like to remove this eager init (in afterPropertiesSet()) of the 
>>>>exception translator. Please let me know if you have a problem with 
>>>>this. I was thinking that if somebody wants to still allow it to be 
>>>>eagerly inited, for the case where JdbcTemplate is coming out of a 
>>>>beanfactory/context then we can add a 'lazyInitExceptionTranslator' 
>>>>property, which would default to true.
>>>>
>>>>Regards,
>>>>Colin
>>>>
>>>>   
>>>>