Optimize timestamp queries: ==, !=, !NULL

[ironage]

Add TimestampNode specializations for: Equal, NotEqual, NotNull.

Here's the timestamp benchmarks for the naïve generic search:

QueryTimestampGreater (MemOnly, EncryptionOff):     min  23.37ms (-50.62%)           max  25.34ms (-57.52%)           med  24.10ms (-56.46%)           avg  24.05ms (-55.09%)           stddev   588us (-86.42%)
QueryTimestampGreater (MemOnly, EncryptionOn):      min  23.34ms (-51.32%)           max  24.95ms (-64.54%)           med  23.79ms (-57.59%)           avg  23.81ms (-57.64%)           stddev   522us (-92.59%)
QueryTimestampGreater (Full   , EncryptionOff):     min  23.38ms (-50.77%)           max     25ms (-58.04%)           med  23.91ms (-56.68%)           avg  23.86ms (-54.99%)           stddev   517us (-88.96%)
QueryTimestampGreater (Full   , EncryptionOn):      min  23.40ms (-50.35%)           max  24.31ms (-59.61%)           med  23.52ms (-56.52%)           avg  23.59ms (-55.92%)           stddev   282us (-93.13%)

QueryTimestampGreaterEqual (MemOnly, EncryptionOff):   min  23.32ms     max  23.81ms     median  23.63ms     avg  23.55ms     stddev    176us
QueryTimestampGreaterEqual (MemOnly, EncryptionOn):    min  23.25ms     max  24.65ms     median  23.58ms     avg  23.63ms     stddev    414us
QueryTimestampGreaterEqual (Full   , EncryptionOff):   min  23.15ms     max  23.59ms     median  23.35ms     avg  23.33ms     stddev    115us
QueryTimestampGreaterEqual (Full   , EncryptionOn):    min  23.27ms     max  23.89ms     median  23.38ms     avg  23.41ms     stddev    187us

QueryTimestampLess (MemOnly, EncryptionOff):           min  23.29ms     max  23.74ms     median  23.40ms     avg  23.45ms     stddev    162us
QueryTimestampLess (MemOnly, EncryptionOn):            min  23.50ms     max  24.61ms     median  23.89ms     avg  23.89ms     stddev    334us
QueryTimestampLess (Full   , EncryptionOff):           min  23.38ms     max  25.02ms     median  24.61ms     avg  24.22ms     stddev    671us
QueryTimestampLess (Full   , EncryptionOn):            min  23.50ms     max  24.21ms     median  23.68ms     avg  23.71ms     stddev    207us

QueryTimestampLessEqual (MemOnly, EncryptionOff):      min  23.30ms     max  23.52ms     median  23.37ms     avg  23.38ms     stddev     84us
QueryTimestampLessEqual (MemOnly, EncryptionOn):       min  23.24ms     max  24.01ms     median  23.54ms     avg  23.50ms     stddev    253us
QueryTimestampLessEqual (Full   , EncryptionOff):      min  23.09ms     max  26.57ms     median  23.43ms     avg  24.04ms     stddev   1.31ms
QueryTimestampLessEqual (Full   , EncryptionOn):       min  23.47ms     max  24.22ms     median  24.08ms     avg  23.95ms     stddev    260us

QueryTimestampEqual (MemOnly, EncryptionOff):          min  18.65ms     max  19.37ms     median  18.75ms     avg  18.80ms     stddev    212us
QueryTimestampEqual (MemOnly, EncryptionOn):           min  18.71ms     max  19.80ms     median  19.08ms     avg  19.04ms     stddev    360us
QueryTimestampEqual (Full   , EncryptionOff):          min  18.92ms     max  19.52ms     median  19.24ms     avg  19.18ms     stddev    223us
QueryTimestampEqual (Full   , EncryptionOn):           min  18.66ms     max  19.19ms     median  18.81ms     avg  18.82ms     stddev    170us

QueryTimestampNotEqual (MemOnly, EncryptionOff):       min  38.87ms     max  40.61ms     median  39.43ms     avg  39.41ms     stddev    560us
QueryTimestampNotEqual (MemOnly, EncryptionOn):        min  38.65ms     max  40.54ms     median  39.53ms     avg  39.50ms     stddev    581us
QueryTimestampNotEqual (Full   , EncryptionOff):       min  39.06ms     max  72.66ms     median  44.69ms     avg  47.36ms     stddev  11.43ms
QueryTimestampNotEqual (Full   , EncryptionOn):        min  38.35ms     max  42.08ms     median  39.75ms     avg  39.65ms     stddev   1.19ms

QueryTimestampNotNull (MemOnly, EncryptionOff):        min  24.29ms     max  25.24ms     median  24.73ms     avg  24.67ms     stddev    281us
QueryTimestampNotNull (MemOnly, EncryptionOn):         min  24.28ms     max  24.78ms     median  24.52ms     avg  24.49ms     stddev    153us
QueryTimestampNotNull (Full   , EncryptionOff):        min  24.19ms     max  25.64ms     median  24.77ms     avg  24.77ms     stddev    461us
QueryTimestampNotNull (Full   , EncryptionOn):         min  24.27ms     max  24.68ms     median  24.47ms     avg  24.46ms     stddev    128us

QueryTimestampEqualNull (MemOnly, EncryptionOff):      min  21.10ms     max  22.17ms     median  21.48ms     avg  21.49ms     stddev    369us
QueryTimestampEqualNull (MemOnly, EncryptionOn):       min  21.08ms     max  22.87ms     median  21.33ms     avg  21.53ms     stddev    606us
QueryTimestampEqualNull (Full   , EncryptionOff):      min     21ms     max  21.47ms     median  21.08ms     avg  21.11ms     stddev    151us
QueryTimestampEqualNull (Full   , EncryptionOn):       min  21.07ms     max  23.57ms     median  21.30ms     avg  21.48ms     stddev    755us

And here's the timestamp benchmarks for this branch:

QueryTimestampGreater (MemOnly, EncryptionOff):     min   7.06ms (-85.09%)           max   7.31ms (-87.74%)           med   7.17ms (-87.04%)           avg   7.17ms (-86.62%)           stddev    87us (-98.00%)
QueryTimestampGreater (MemOnly, EncryptionOn):      min   7.06ms (-85.28%)           max   7.23ms (-89.72%)           med   7.13ms (-87.28%)           avg   7.13ms (-87.32%)           stddev    61us (-99.14%)
QueryTimestampGreater (Full   , EncryptionOff):     min   7.05ms (-85.15%)           max   7.31ms (-87.73%)           med   7.12ms (-87.10%)           avg   7.13ms (-86.55%)           stddev    72us (-98.45%)
QueryTimestampGreater (Full   , EncryptionOn):      min   7.10ms (-84.95%)           max   7.37ms (-87.76%)           med   7.19ms (-86.70%)           avg   7.19ms (-86.56%)           stddev    94us (-97.70%)

QueryTimestampGreaterEqual (MemOnly, EncryptionOff):   min   7.20ms     max   7.69ms     median   7.31ms     avg   7.38ms     stddev    155us
QueryTimestampGreaterEqual (MemOnly, EncryptionOn):    min   7.20ms     max   7.36ms     median   7.28ms     avg   7.27ms     stddev     49us
QueryTimestampGreaterEqual (Full   , EncryptionOff):   min   7.20ms     max   7.92ms     median   7.28ms     avg   7.33ms     stddev    191us
QueryTimestampGreaterEqual (Full   , EncryptionOn):    min   7.81ms     max  23.72ms     median  10.88ms     avg  12.02ms     stddev   4.66ms

QueryTimestampLess (MemOnly, EncryptionOff):           min   6.54ms     max   7.68ms     median   6.75ms     avg   6.82ms     stddev    350us
QueryTimestampLess (MemOnly, EncryptionOn):            min   6.54ms     max   7.25ms     median   6.78ms     avg   6.78ms     stddev    186us
QueryTimestampLess (Full   , EncryptionOff):           min   6.58ms     max   8.57ms     median   7.54ms     avg   7.49ms     stddev    508us
QueryTimestampLess (Full   , EncryptionOn):            min   6.55ms     max   7.44ms     median   6.67ms     avg   6.70ms     stddev    240us

QueryTimestampLessEqual (MemOnly, EncryptionOff):      min   6.72ms     max   7.23ms     median   6.90ms     avg   6.91ms     stddev    123us
QueryTimestampLessEqual (MemOnly, EncryptionOn):       min   6.99ms     max   8.63ms     median   7.79ms     avg   7.72ms     stddev    578us
QueryTimestampLessEqual (Full   , EncryptionOff):      min   6.69ms     max   8.42ms     median   6.83ms     avg   7.01ms     stddev    526us
QueryTimestampLessEqual (Full   , EncryptionOn):       min   6.72ms     max   7.07ms     median   6.78ms     avg   6.82ms     stddev    108us

QueryTimestampEqual (MemOnly, EncryptionOff):          min   1.08ms     max   1.54ms     median   1.10ms     avg   1.12ms     stddev     71us
QueryTimestampEqual (MemOnly, EncryptionOn):           min   1.10ms     max   1.28ms     median   1.10ms     avg   1.11ms     stddev     30us
QueryTimestampEqual (Full   , EncryptionOff):          min   1.08ms     max   1.30ms     median   1.10ms     avg   1.11ms     stddev     39us
QueryTimestampEqual (Full   , EncryptionOn):           min   1.10ms     max   1.84ms     median   1.11ms     avg   1.15ms     stddev    110us

QueryTimestampNotEqual (MemOnly, EncryptionOff):       min  25.91ms     max  31.94ms     median  26.37ms     avg  27.03ms     stddev   1.89ms
QueryTimestampNotEqual (MemOnly, EncryptionOn):        min  25.75ms     max  28.38ms     median  26.68ms     avg  26.57ms     stddev    885us
QueryTimestampNotEqual (Full   , EncryptionOff):       min  25.94ms     max  27.66ms     median  26.72ms     avg  26.70ms     stddev    551us
QueryTimestampNotEqual (Full   , EncryptionOn):        min  25.54ms     max  26.70ms     median     26ms     avg  25.96ms     stddev    363us

QueryTimestampNotNull (MemOnly, EncryptionOff):        min  12.58ms     max  13.13ms     median  12.73ms     avg  12.76ms     stddev    172us
QueryTimestampNotNull (MemOnly, EncryptionOn):         min  12.74ms     max  13.64ms     median  13.10ms     avg  13.14ms     stddev    310us
QueryTimestampNotNull (Full   , EncryptionOff):        min  12.71ms     max  14.40ms     median  13.60ms     avg  13.38ms     stddev    584us
QueryTimestampNotNull (Full   , EncryptionOn):         min  12.75ms     max  13.73ms     median  13.38ms     avg  13.26ms     stddev    333us

QueryTimestampEqualNull (MemOnly, EncryptionOff):      min   3.66ms     max   4.07ms     median   3.75ms     avg   3.79ms     stddev    126us
QueryTimestampEqualNull (MemOnly, EncryptionOn):       min   3.66ms     max   3.91ms     median   3.68ms     avg   3.71ms     stddev     63us
QueryTimestampEqualNull (Full   , EncryptionOff):      min   3.65ms     max   3.78ms     median   3.68ms     avg   3.69ms     stddev     36us
QueryTimestampEqualNull (Full   , EncryptionOn):       min   3.67ms     max   3.86ms     median   3.72ms     avg   3.73ms     stddev     60us

[jedelbo]

I was able to squeeze it a bit more. A simple optimization in Array::find_optimized paid well off.
These are the improvements compared to the commit that gave the numbers above.

QueryTimestampGreater (MemOnly, EncryptionOff):     min   7.80ms (-5.85%)            max   7.93ms (-4.78%)            med   7.81ms (-6.06%)            avg   7.82ms (-5.89%)            stddev    36us (+114.87%)     
QueryTimestampGreater (MemOnly, EncryptionOn):      min   7.82ms (-5.51%)            max   7.96ms (-4.28%)            med   7.91ms (-4.66%)            avg   7.91ms (-4.62%)            stddev    37us (+224.19%)     
QueryTimestampGreater (Full   , EncryptionOff):     min   7.81ms (-5.74%)            max   7.85ms (-7.33%)            med   7.83ms (-6.54%)            avg   7.83ms (-6.71%)            stddev    11us (-86.54%)      
QueryTimestampGreater (Full   , EncryptionOn):      min   7.82ms (-5.70%)            max   7.89ms (-5.45%)            med   7.84ms (-5.65%)            avg   7.84ms (-5.61%)            stddev    18us (+13.93%)      

QueryTimestampGreaterEqual (MemOnly, EncryptionOff):     min   7.64ms (-8.30%)            max   7.73ms (-8.67%)            med   7.64ms (-8.33%)            avg   7.65ms (-8.34%)            stddev    26us (-32.48%)      
QueryTimestampGreaterEqual (MemOnly, EncryptionOn):      min   7.64ms (-8.19%)            max   7.75ms (-7.53%)            med   7.66ms (-8.06%)            avg   7.68ms (-7.94%)            stddev    40us (+94.54%)      
QueryTimestampGreaterEqual (Full   , EncryptionOff):     min   7.62ms (-9.13%)            max   7.69ms (-11.20%)           med   7.63ms (-10.79%)           avg   7.64ms (-10.22%)           stddev    19us (-82.88%)      
QueryTimestampGreaterEqual (Full   , EncryptionOn):      min   7.64ms (-8.00%)            max   7.69ms (-8.91%)            med   7.66ms (-8.61%)            avg   7.66ms (-8.47%)            stddev    14us (-66.94%)      

QueryTimestampLess (MemOnly, EncryptionOff):             min   7.66ms (-9.38%)            max   7.72ms (-8.82%)            med   7.69ms (-9.16%)            avg   7.68ms (-9.18%)            stddev    20us (+241.73%)     
QueryTimestampLess (MemOnly, EncryptionOn):              min   7.70ms (-9.25%)            max   7.73ms (-9.73%)            med   7.72ms (-9.70%)            avg   7.71ms (-9.56%)            stddev    10us (-58.71%)      
QueryTimestampLess (Full   , EncryptionOff):             min   7.68ms (-9.22%)            max   7.76ms (-8.68%)            med   7.71ms (-9.02%)            avg   7.70ms (-9.08%)            stddev    27us (+53.37%)      
QueryTimestampLess (Full   , EncryptionOn):              min   7.68ms (-9.26%)            max   7.75ms (-8.65%)            med   7.70ms (-9.12%)            avg   7.70ms (-9.08%)            stddev    26us (+168.02%)     

QueryTimestampLessEqual (MemOnly, EncryptionOff):        min   7.73ms (-6.85%)            max   7.78ms (-6.50%)            med   7.75ms (-6.63%)            avg   7.75ms (-6.68%)            stddev    19us (+120.61%)     
QueryTimestampLessEqual (MemOnly, EncryptionOn):         min   7.74ms (-6.98%)            max   7.78ms (-7.23%)            med   7.76ms (-6.98%)            avg   7.76ms (-7.01%)            stddev    16us (-17.55%)      
QueryTimestampLessEqual (Full   , EncryptionOff):        min   7.73ms (-6.92%)            max   7.81ms (-7.99%)            med   7.75ms (-8.06%)            avg   7.75ms (-7.82%)            stddev    23us (-66.96%)      
QueryTimestampLessEqual (Full   , EncryptionOn):         min   7.75ms (-7.05%)            max   7.84ms (-6.63%)            med   7.79ms (-6.75%)            avg   7.79ms (-6.79%)            stddev    33us (+75.85%)      

QueryTimestampEqual (MemOnly, EncryptionOff):            min    882us (-40.98%)           max    938us (-38.51%)           med    884us (-40.94%)           avg    885us (-40.93%)           stddev     6us (+0.78%)       
QueryTimestampEqual (MemOnly, EncryptionOn):             min    893us (-40.74%)           max    900us (-43.82%)           med    895us (-40.79%)           avg    895us (-41.29%)           stddev     2us (-93.73%)      
QueryTimestampEqual (Full   , EncryptionOff):            min    882us (-40.99%)           max    967us (-39.88%)           med    884us (-41.10%)           avg    887us (-41.56%)           stddev    11us (-63.36%)      
QueryTimestampEqual (Full   , EncryptionOn):             min    894us (-40.69%)           max    934us (-42.52%)           med    895us (-42.43%)           avg    897us (-42.03%)           stddev     5us (-82.14%)      

QueryTimestampNotEqual (MemOnly, EncryptionOff):         min  13.43ms (-54.78%)           max  13.59ms (-54.49%)           med  13.54ms (-54.55%)           avg  13.50ms (-54.67%)           stddev    59us (+19.57%)      
QueryTimestampNotEqual (MemOnly, EncryptionOn):          min  13.44ms (-54.89%)           max  13.58ms (-54.56%)           med  13.54ms (-54.61%)           avg  13.50ms (-54.73%)           stddev    56us (+73.53%)      
QueryTimestampNotEqual (Full   , EncryptionOff):         min  13.39ms (-55.16%)           max  13.54ms (-55.09%)           med  13.52ms (-54.81%)           avg  13.47ms (-55.01%)           stddev    64us (-25.45%)      
QueryTimestampNotEqual (Full   , EncryptionOn):          min  13.47ms (-55.60%)           max  13.64ms (-56.20%)           med  13.60ms (-56.09%)           avg  13.56ms (-56.07%)           stddev    68us (-70.62%)      

QueryTimestampNotNull (MemOnly, EncryptionOff):          min  14.25ms (-5.77%)            max  14.31ms (-8.73%)            med  14.30ms (-5.77%)            avg  14.28ms (-6.17%)            stddev    28us (-83.88%)      
QueryTimestampNotNull (MemOnly, EncryptionOn):           min  14.19ms (-5.96%)            max  14.28ms (-7.43%)            med  14.24ms (-6.14%)            avg  14.23ms (-6.28%)            stddev    31us (-75.08%)      
QueryTimestampNotNull (Full   , EncryptionOff):          min  14.23ms (-5.67%)            max  14.30ms (-6.65%)            med  14.26ms (-5.80%)            avg  14.26ms (-5.86%)            stddev    26us (-65.96%)      
QueryTimestampNotNull (Full   , EncryptionOn):           min  14.20ms (-6.02%)            max  14.29ms (-5.86%)            med  14.27ms (-5.82%)            avg  14.26ms (-5.88%)            stddev    26us (+14.03%)      

QueryTimestampEqualNull (MemOnly, EncryptionOff):        min   3.87ms (-9.52%)            max   3.90ms (-9.52%)            med   3.88ms (-9.34%)            avg   3.88ms (-9.38%)            stddev     8us (-6.84%)       
QueryTimestampEqualNull (MemOnly, EncryptionOn):         min   3.87ms (-9.61%)            max   3.90ms (-9.13%)            med   3.89ms (-9.51%)            avg   3.89ms (-9.51%)            stddev     7us (+139.19%)     
QueryTimestampEqualNull (Full   , EncryptionOff):        min   3.87ms (-9.65%)            max   3.90ms (-9.42%)            med   3.88ms (-9.31%)            avg   3.88ms (-9.40%)            stddev    10us (+90.95%)      
QueryTimestampEqualNull (Full   , EncryptionOn):         min   3.88ms (-9.66%)            max   3.90ms (-10.66%)           med   3.89ms (-9.46%)            avg   3.89ms (-9.60%)            stddev     7us (-59.88%)