[SR-Users] Hash Table capacity

[Elena-Ramona Modroiu]

Hi,

On 8/19/13 4:05 PM, Alex Balashov wrote:
> According the docs, the hash table is restricted to a maximum size of 
> 2^16 (65536) buckets.
it was restricted to 2^14, I just lifted it to positive integer range 
2^31 because it is easier to get now systems with plenty of memory -- it 
will be in next major release.

>
> This doesn't mean that the htable can only hold 65k entries, just that 
> it's the maximum number of unique buckets. Assuming a theoretically 
> ideal distribution where every value has a unique bucket, after 65k 
> values, you will get collisions. Collision chains attached to buckets 
> are linear lists. After collision chains get deep, performance becomes 
> more and more linear.
>
> So, you can put 2m values into the htable. I am not sure that it is 
> the optimal use of an htable, however.

With the previous upper limit (2^14) you could get a fair distribution 
of about 125 items per slot, which is still fine for linear searching, 
provided a modern CPU server.

You can simulate some tests and measure the search performances with 
benchmark module.

Regards,
Ramona

>
>
> Ricardo Martinez <rmartinez at redvoiss.net> wrote:
>
>     Anyone here?
>
>     Thanks!
>
>     Ricardo.-
>
>     *De:*Ricardo Martinez [mailto:rmartinez at redvoiss.net
>     <mailto:rmartinez at redvoiss.net>]
>     *Enviado el:* miércoles, 14 de agosto de 2013 18:34
>     *Para:* sr-users at lists.sip-router.org
>     <mailto:sr-users at lists.sip-router.org>
>     *Asunto:* Hash Table capacity
>
>     Hello list.
>
>     I have a question about the HTABLE module.  Suppose that I have a
>     mysql database with 2 million of records.  Is possible to load
>     this table as a hash table compatible with Kamailio!?
>
>     Hope someone can help me.
>
>     Thanks,
>     Ricardo Martinez.-
>
>     ------------------------------------------------------------------------
>
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>
> --
> Sent from my mobile, and thus lacking in the refinement one might 
> expect from a fully fledged keyboard.
>
> Alex Balashov - Principal
> Evariste Systems LLC
> 235 E Ponce de Leon Ave
> Suite 106
> Decatur, GA 30030
> United States
> Tel: +1-678-954-0670
> Web: http://www.evaristesys.com/, http://www.alexbalashov.com
>
>
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