Patch submission for comments : CGI speed improvement (XNG)

[Andreas Ericsson]

François Laupretre wrote:
>>Here is a patch I am submitting to your comments. The purpose 
>>of this patch is to bring a solution to the CGI performance 
>>problem met on configuration with several thousands of hosts/services.
>>...
> 
> 
> Hello everybody,
> 
> As I didn't have any reply, do I have to consider that it does not interest
> anybody ?
> 

Yes and no. The comments were in french, much of the code wasn't 
indented and mnemonic identifiers doesn't appear to be in the 
programming style you use, so it took a while to grok all of it.

> Sorry to insist but I thought that it could be a solution (good or bad...)
> to a real issue. And, as more and more people switch to Nagios V 2, this
> problem will become more important.
> 

A simpler solution to the same problem would be to implement real 
hashing instead of the algorithm in current use. Presently it generates 
worse hashes than an internet checksum function and the 
compare_hashdata* functions (called from find_*) are extremely expensive.

> If you consider that nagios-db is THE ultimate solution, I don't agree, but
> let me know, and I won't disturb you any more.
> 

nagios-db isn't the ultimate solution, although using a database is far 
superior to flat-files (regardless of format).

I'm not so sure about this patch you've proposed though. By necessity it 
involves a fair deal of pointer voodoo. Code such as that is always hell 
to maintain, and it gets increasingly difficult to ensure support for 
various compilers and architectures. F.e., gcc aligns components of 
datastructures on sizeof(register) boundaries with certain optimization 
options, and squeezes them with others, making pointer-hopping using 
anything but relative offsets a debugging nightmare. Other compilers 
have similar symptoms.

-- 
Andreas Ericsson                   andreas.ericsson at op5.se
OP5 AB                             www.op5.se
Lead Developer


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