BIND 10 #1750: add "at origin" option in ZoneFinder::find() and support it in in-memory

[BIND 10 Development]

#1750: add "at origin" option in ZoneFinder::find() and support it in in-memory
-------------------------------------+-------------------------------------
                   Reporter:         |                 Owner:  jinmei
  jinmei                             |                Status:  reviewing
                       Type:  task   |             Milestone:
                   Priority:  high   |  Sprint-20120501
                  Component:  data   |            Resolution:
  source                             |             Sensitive:  0
                   Keywords:         |           Sub-Project:  DNS
            Defect Severity:  N/A    |  Estimated Difficulty:  4
Feature Depending on Ticket:  auth   |           Total Hours:  0
  performance                        |
        Add Hours to Ticket:  0      |
                  Internal?:  0      |
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Changes (by vorner):

 * owner:  vorner => jinmei


Comment:

 Hello

 I merged with master and tried again. The test was with the `query_bench`
 tool, `-O2` optimisations. The test data was a small real-life zone (73
 records), I picked few records that were and few that were not in the zone
 for the queries.

 Since the merge was not really trivial, I placed it as `trac1750-merged`
 branch into git for possible review. But I think it won't be needed,
 because the benchmarks show the optimisation gives nothing (it is actually
 slower with the branch than without, which might be some kind of code
 complexity issue, or benchmark inaccuracy, as the difference is rather
 small).

 Without the optimisation:
 {{{
 $ ./query_bench -n 1000000 -t memory -o sury.org. ~/zone ~/x
 Parameters:
   Iterations: 1000000
   Data Source: type=memory, file=/home/vorner/zone
   Origin: sury.org.
   Query data: file=/home/vorner/x (9 queries)

 Benchmark with In Memory Data Source
 Processed 9000000 queries in 49.463844s (181951.08qps)
 }}}

 And with the optimisation:
 {{{
 $ ./query_bench -n 1000000 -t memory -o sury.org. ~/zone ~/x
 Parameters:
   Iterations: 1000000
   Data Source: type=memory, file=/home/vorner/zone
   Origin: sury.org.
   Query data: file=/home/vorner/x (9 queries)

 Benchmark with In Memory Data Source
 Processed 9000000 queries in 49.819539s (180652.01qps)
 }}}

 So, could you have a quick look if I did something obviously stupid in the
 merge? If not, I propose to drop the branch.

 Thank you

-- 
Ticket URL: <http://bind10.isc.org/ticket/1750#comment:13>
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