[jboss-dev] AS trunk boot time back to poor?

[David M. Lloyd]

On 01/21/2010 04:50 PM, Brian Stansberry wrote:
> On 01/21/2010 11:20 AM, Brian Stansberry wrote:
>> On 01/21/2010 10:41 AM, David M. Lloyd wrote:
>>> On 01/21/2010 10:39 AM, David M. Lloyd wrote:
>>>> On 01/21/2010 09:55 AM, Brian Stansberry wrote:
>>
>> Semi-OT: a couple weeks ago, when boot.log was<   10MB I tried setting
>> -Djboss.boot.server.log.level=INFO and got very little improvement in
>> boot time (<   200ms). My take on that is we must have a lot of DEBUG
>> logging with very expensive message construction not guarded by
>> isDebugEnabled().
>
> John Bailey did some quick profiling or something and estimated that
> during startup we have>  5000 log.debug() calls not guarded by
> log.isDebugEnabled(). If you look at the debug logging output, a lot of
> the messages are pretty heavy, some absolutely huge; if those aren't
> guarded it's a serious cost.
[...]
> I fear though that deprecating this method is a failed social
> experiment. Please resist the urge to make that deprecation warning go
> away by not putting a code guard around an expensive log.debug(). Either
> reduce the level to trace (and keep a guard of course) or accept the
> warning and bitch publicly about the deprecation.

Another alternative is to use the debugf variant instead of concatenation:

    log.debugf("Something happened with %s on a %s for %s", foo, bar, baz);

This will avoid the expense of concatenation and toString when debug 
logging isn't enabled (which is the most common case I think), however it 
won't avoid other types of expensive computations.

- DML