Re: (ITS#8875) [Patch] Performance problems in back-mdb with large DITs and many aliases

[hyc@symas.com]

henrik.bohnenkamp@ionos.com wrote:
> On Fri, Jan 25, 2019 at 06:31:41AM -0800, Quanah Gibson-Mount wrote:
>> --On Friday, January 25, 2019 1:51 PM +0000 hbohnenkamp@united-internet.de
>> wrote:
>>

Hi, thanks for the report and investigation. I've briefly reviewed your
patches. Please squash your #3 into #2, there's no reason to preserve that.

We don't use "inline" in this code. If the compiler is smart enough it will
inline automatically anyway. Please drop that from your patch.

No need to keep the old mdb_idscope invocation commented out in patch #2.
Just delete it, we have the git history.

In patch #1 delete.c your patch line #145 is incorrect. You should be
using is_entry_alias(e) instead of (op->ora_e.) The entry in question is not
part of the op request, only its DN is in the Delete request.

Not sure why you dropped nsubs from the diskNode definition. Are you sure you
haven't broken the nsubs processing in this patch?

> 
> Hi,
> 
> I have now done quite a lot of testing in the way described in my
> email from January (Followup 3). I used version 2.4.47, not the HEAD
> of the openldap git master branch.
> 
> I have found one bug, the one mentioned already in the same email. I
> have added a fix for that bug to the patch directory in
> https://github.com/hbo/openldap-mdb-deref-problem
> 
> I have come across the regression with the back-hdb backend again,
> which I also described in my previous email already.  I am now
> convinced that this regression is really a problem with the back-hdb
> implementation, and I can show it without using my patched
> implementation of back-mdb. The demonstration requires a bit more work
> to be really presentable and should in any case go into a different
> bug report.
> 
> Apart from these two issues I have not seen any regressions, and I am
> now quite confident that my patch would work reliable in the
> environment of my company... no guarantees for anything else :-)  
> 
> I have seen that Quanah has suggested to look at ITS#8875 for the
> 2.4.48 release. Whether there will be a fix in 2.4.48 and whether it
> will be based on my patch is of course up to the lead developers (the
> change in the DB schema is certainly a strong point against), but this
> patch can perhaps serve as something to test the actual fix against.
> 
> Best regards
> Henrik
> 
> 
> --
> Henrik Bohnenkamp
> 
> 
> 
> 


-- 
  -- Howard Chu
  CTO, Symas Corp.           http://www.symas.com
  Director, Highland Sun     http://highlandsun.com/hyc/
  Chief Architect, OpenLDAP  http://www.openldap.org/project/