26 Apr
2010
26 Apr
'10
1:22 p.m.
The htable size is static; it doesn't dynamically resize itself up to
the next power of 2 after a certain utilisation threshold, right?
--
Alex Balashov - Principal
Evariste Systems LLC
1170 Peachtree Street
12th Floor, Suite 1200
Atlanta, GA 30309
Tel: +1-678-954-0670
Fax: +1-404-961-1892
Web: http://www.evaristesys.com/
26 Apr
26 Apr
1:31 p.m.
On Monday 26 April 2010, Alex Balashov wrote:
The htable size is static; it doesn't dynamically
resize itself up to
the next power of 2 after a certain utilisation threshold, right?
Hi Alex,
i think this is a static setting, as the memory is allocated on startup in
shared memory. Do you've run into performance problems or memory size
constraints with the htable module?
Regards,
Henning
1:32 p.m.
On 04/26/2010 07:31 AM, Henning Westerholt wrote:
On Monday 26 April 2010, Alex Balashov wrote:
None whatsoever, I was just curious from a theoretical perspective.
The answer lets me know in an a priori way whether the htable is optimal
for applications involving rapidly shrinking or contracting data sets,
by several factors.
--
Alex Balashov - Principal
Evariste Systems LLC
1170 Peachtree Street
12th Floor, Suite 1200
Atlanta, GA 30309
Tel: +1-678-954-0670
Fax: +1-404-961-1892
Web: http://www.evaristesys.com/
The htable size is static; it doesn't
dynamically resize itself up to
the next power of 2 after a certain utilisation threshold, right?
Hi Alex,
i think this is a static setting, as the memory is allocated on startup in
shared memory. Do you've run into performance problems or memory size
constraints with the htable module?
1:48 p.m.
On Monday 26 April 2010, Alex Balashov wrote:
There is probably a certain point on which further increase of the htable size
make not that much sense anymore. It seems the module only supports from 256
to 16384 buckets in the htable. So depending on the distribution of the hash
function the htable will start to degenerate, up to a worst case complexity to
O(n). The used function is core_case_hash from hash_func.c
Regards,
Henning
i think this
is a static setting, as the memory is allocated on startup
in shared memory. Do you've run into performance problems or memory size
constraints with the htable module?
None whatsoever, I was just curious from a theoretical perspective.
The answer lets me know in an a priori way whether the htable is optimal
for applications involving rapidly shrinking or contracting data sets,
by several factors.
1:51 p.m.
On 04/26/2010 07:48 AM, Henning Westerholt wrote:
On Monday 26 April 2010, Alex Balashov wrote:
There is probably a certain point on which further increase of the htable size
make not that much sense anymore. It seems the module only supports from 256
to 16384 buckets in the htable. So depending on the distribution of the hash
function the htable will start to degenerate, up to a worst case complexity to
O(n). The used function is core_case_hash from hash_func.c
Indeed, I asked this question after seeing your git commit to the
documentation that specifies that maximum dimension is 2^14.
Is there a particular reason for the cap to be at 2^14?
--
Alex Balashov - Principal
Evariste Systems LLC
1170 Peachtree Street
12th Floor, Suite 1200
Atlanta, GA 30309
Tel: +1-678-954-0670
Fax: +1-404-961-1892
Web: http://www.evaristesys.com/
i think
this is a static setting, as the memory is allocated on startup
in shared memory. Do you've run into performance problems or memory size
constraints with the htable module?
None whatsoever, I was just curious from a theoretical perspective.
The answer lets me know in an a priori way whether the htable is optimal
for applications involving rapidly shrinking or contracting data sets,
by several factors.
2:04 p.m.
On Monday 26 April 2010, Alex Balashov wrote:
I also wondered about this restriction, i thought e.g. 2^16 would be possible
to configure. But probably Daniel can comment on this, perhaps there is some
restriction in the design of the module?
Henning
There is
probably a certain point on which further increase of the htable
size make not that much sense anymore. It seems the module only supports
from 256 to 16384 buckets in the htable. So depending on the distribution
of the hash function the htable will start to degenerate, up to a worst
case complexity to O(n). The used function is core_case_hash from
hash_func.c
Indeed, I asked this question after seeing your git commit to the
documentation that specifies that maximum dimension is 2^14.
Is there a particular reason for the cap to be at 2^14?
5117
days inactive
5117
days old
5 comments
2 participants
participants (2)
-
Alex Balashov -
Henning Westerholt