winbindd_cache.tdb size issue in 3.2.15

[Jeremy Allison]

On Fri, Oct 30, 2009 at 04:50:58PM +0100, valyekhin at aidoss.com wrote:
> Hello.
>
> After update Samba from v. 3.0.28a to v.  3.2.15 we've noticed that  
> winbibdd_cache.tdb file has been increased up to 10 times. After some  
> testing we got the following file sizes (in bytes)
>
> 6 users in AD:  3.0.28a - 53248, 3.2.15 - 389120
> 1005 users in AD: 0.28a - 1802240, 3.2.15 - 13963264
> 10005 users in AD: 0.28a - 18464768, 3.2.15 - 144846848
>
> We've found out that 3.2.15 uses another algorythm for making room for  
> new records in the tdb file. If 3.0.28a allocates space for at least 10 
> more records, 3.2.15 allocates space for at least 100 more records, and 
> at least 25% more space.
> We've created a patch which transfers algorythm for allocation space from
> 3.0.28a.
> After using this patch we've got the next results:
> 6 users in AD:  3.0.28a - 53248, 3.2.15 patched - 61440
> 1005 users in AD: 0.28a - 1802240, 3.2.15 patched - 1922916
> 10005 users in AD: 0.28a - 18464768, 3.2.15 patched - 19709952
>
> But we have some doubts as for the correctness of the patch and we're  
> not sure that it won't damage anything.
>
> Please, clarify this item.

The increase in size is by design as it helps prevent fragmentation
in the tdb files. Why is the increased size causing a problem for you ?

Jeremy.