Sequence folding in parallel case

[ThomasArts]

An unexpeced effect in book_objectfold/5

In a sequential prefix, we put an element in the store and then define a sqn_order object fold over this store with snapshot false. Then in parallel we run the fold and put one more oject in the store. That new object has the same bucket and key, but other value.

Now, I would expect to see as outcome of the fold either the first or the second put for that key. But I see both. And worst, I see the one put in first as last in the outcome of the fold!

Sequential prefix:

   leveledjc_eqc:init_backend(o_rkv,
       [{root_path, Dir}, {log_level, error}, {max_sstslots, 2},
        {cache_size, 10}, {max_pencillercachesize, 40},
        {max_journalsize, 20000}],
       sut) ->
     <0.8007.0>
   leveledjc_eqc:put(<0.8007.0>, <<98, 117, 99, 107, 101, 116, 49>>,
       <<2, 201, 141, 204, 220, 59, 44, 47, 23, 186, 96, 213, 119, 114,
         228, 125>>, 
       <<53, 1, 0, 0, 0, 95, 131, 108, 0, 0, 0, 7, 104, 2, 100, 0, 5,
         99, 108, 97, 114, 97, 97, 1, 104, 2, 100, 0, 6, 103, 101, 111,
         114, 103, 101, 97, 2, 104, 2, 100, 0, 5, 105, 115, 97, 97, 99,
         97, 3, 104, 2, 100, 0, 6, 103, 101, 111, 114, 103, 101, 97, 4,
         104, 2, 100, 0, 5, 105, 115, 97, 97, 99, 97, 5, 104, 2, 100, 0,
         6, 98, 101, 114, 116, 105, 101, 97, 6, 104, 2, 100, 0, 6, 98,
         101, 114, 116, 105, 101, 97, 7, 106, 0, 0, 0, 1, 0, 0, 1, 1, 1,
         102, 36, 5, 193, 191, 22, 53, 85, 105, 9, 89, 22, 207, 140, 34,
         144, 26, 113, 202, 213, 62, 36, 201, 186, 215, 182, 172, 163,
         168, 32, 169, 143, 244, 224, 244, 47, 8, 241, 201, 191, 3, 204,
         240, 248, 81, 29, 117, 128, 186, 180, 245, 171, 195, 63, 193, 13,
         91, 149, 200, 208, 128, 134, 245, 55, 171, 68, 159, 232, 243,
         169, 26, 45, 218, 179, 52, 49, 64, 133, 46, 134, 137, 117, 161,
         84, 146, 174, 66, 134, 42, 113, 221, 75, 57, 180, 187, 228, 174,
         30, 162, 89, 161, 26, 69, 230, 47, 144, 108, 47, 252, 212, 25,
         106, 48, 169, 204, 252, 98, 182, 21, 70, 179, 123, 132, 232, 103,
         66, 168, 91, 20, 69, 118, 109, 104, 170, 251, 52, 234, 164, 214,
         255, 228, 149, 213, 41, 225, 205, 3, 161, 242, 249, 233, 30, 43,
         54, 66, 123, 244, 61, 139, 43, 190, 192, 24, 244, 126, 245, 131,
         15, 29, 146, 230, 223, 194, 133, 35, 52, 166, 116, 107, 0, 12,
         119, 142, 221, 64, 90, 110, 6, 38, 17, 57, 66, 212, 80, 82, 35,
         123, 184, 31, 107, 35, 105, 125, 181, 82, 27, 215, 109, 232, 86,
         47, 13, 74, 126, 254, 199, 239, 128, 87, 79, 145, 123, 19, 162,
         111, 93, 191, 111, 187, 29, 243, 68, 205, 72, 140, 41, 228, 145,
         69, 122, 124, 24, 61, 106, 57, 136, 166, 97, 189, 213, 98, 147,
         189, 86, 56, 182, 0, 0, 0, 15, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
         0, 1, 101, 0>>,
       [], o_rkv) ->
     ok
   leveledjc_eqc:objectfold(<0.8007.0>, o_rkv, {#Fun<leveledjc_eqc.30.115929979>, []},
       false, sqn_order, 1) ->
     #Fun<leveled_runner.10.81953218>

Parallel:

1. leveledjc_eqc:fold_run(1, #Fun<leveled_runner.10.81953218>) ->
  [{<<98, 117, 99, 107, 101, 116, 49>>,
    <<2, 201, 141, 204, 220, 59, 44, 47, 23, 186, 96, 213, 119, 114,
      228, 125>>,
    <<53, 1, 0, 0, 0, 19, 131, 108, 0, 0, 0, 1, 104, 2, 100, 0, 5,
      105, 115, 97, 97, 99, 97, 1, 106, 0, 0, 0, 1, 0, 0, 1, 1, 1, 72,
      91, 51, 204, 93, 141, 134, 68, 135, 44, 79, 97, 32, 185, 231,
      207, 84, 127, 250, 100, 210, 95, 245, 171, 156, 134, 222, 162,
      47, 129, 81, 120, 132, 168, 55, 144, 18, 85, 77, 170, 49, 126,
      18, 189, 102, 97, 237, 249, 94, 128, 210, 250, 229, 70, 105, 152,
      31, 252, 224, 41, 145, 232, 23, 60, 58, 72, 178, 225, 10, 115,
      245, 230, 237, 114, 135, 88, 208, 125, 180, 210, 250, 76, 207,
      188, 96, 14, 32, 63, 88, 2, 254, 127, 79, 103, 22, 52, 250, 194,
      153, 168, 48, 166, 102, 210, 76, 247, 226, 137, 221, 24, 65, 76,
      66, 201, 130, 119, 55, 12, 129, 93, 131, 104, 83, 15, 233, 183,
      114, 223, 41, 229, 237, 12, 50, 219, 192, 184, 172, 77, 110, 176,
      103, 118, 10, 156, 113, 126, 52, 106, 144, 128, 125, 116, 115,
      11, 93, 149, 30, 180, 182, 68, 61, 186, 235, 113, 157, 211, 85,
      50, 78, 24, 184, 222, 14, 147, 172, 232, 100, 98, 252, 201, 22,
      83, 174, 16, 79, 30, 151, 164, 144, 17, 132, 172, 44, 41, 222,
      216, 235, 108, 160, 84, 83, 201, 212, 42, 176, 140, 202, 50, 236,
      14, 222, 111, 143, 44, 54, 98, 7, 122, 164, 21, 218, 195, 45,
      189, 97, 70, 17, 194, 53, 12, 248, 115, 166, 82, 5, 7, 76, 145,
      169, 253, 120, 219, 239, 105, 76, 9, 152, 34, 25, 198, 253, 50,
      132, 12, 94, 55, 0, 0, 0, 15, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      1, 101, 0>>},
   {<<98, 117, 99, 107, 101, 116, 49>>,
    <<2, 201, 141, 204, 220, 59, 44, 47, 23, 186, 96, 213, 119, 114,
      228, 125>>,
    <<53, 1, 0, 0, 0, 95, 131, 108, 0, 0, 0, 7, 104, 2, 100, 0, 5,
      99, 108, 97, 114, 97, 97, 1, 104, 2, 100, 0, 6, 103, 101, 111,
      114, 103, 101, 97, 2, 104, 2, 100, 0, 5, 105, 115, 97, 97, 99,
      97, 3, 104, 2, 100, 0, 6, 103, 101, 111, 114, 103, 101, 97, 4,
      104, 2, 100, 0, 5, 105, 115, 97, 97, 99, 97, 5, 104, 2, 100, 0,
      6, 98, 101, 114, 116, 105, 101, 97, 6, 104, 2, 100, 0, 6, 98,
      101, 114, 116, 105, 101, 97, 7, 106, 0, 0, 0, 1, 0, 0, 1, 1, 1,
      102, 36, 5, 193, 191, 22, 53, 85, 105, 9, 89, 22, 207, 140, 34,
      144, 26, 113, 202, 213, 62, 36, 201, 186, 215, 182, 172, 163,
      168, 32, 169, 143, 244, 224, 244, 47, 8, 241, 201, 191, 3, 204,
      240, 248, 81, 29, 117, 128, 186, 180, 245, 171, 195, 63, 193, 13,
      91, 149, 200, 208, 128, 134, 245, 55, 171, 68, 159, 232, 243,
      169, 26, 45, 218, 179, 52, 49, 64, 133, 46, 134, 137, 117, 161,
      84, 146, 174, 66, 134, 42, 113, 221, 75, 57, 180, 187, 228, 174,
      30, 162, 89, 161, 26, 69, 230, 47, 144, 108, 47, 252, 212, 25,
      106, 48, 169, 204, 252, 98, 182, 21, 70, 179, 123, 132, 232, 103,
      66, 168, 91, 20, 69, 118, 109, 104, 170, 251, 52, 234, 164, 214,
      255, 228, 149, 213, 41, 225, 205, 3, 161, 242, 249, 233, 30, 43,
      54, 66, 123, 244, 61, 139, 43, 190, 192, 24, 244, 126, 245, 131,
      15, 29, 146, 230, 223, 194, 133, 35, 52, 166, 116, 107, 0, 12,
      119, 142, 221, 64, 90, 110, 6, 38, 17, 57, 66, 212, 80, 82, 35,
      123, 184, 31, 107, 35, 105, 125, 181, 82, 27, 215, 109, 232, 86,
      47, 13, 74, 126, 254, 199, 239, 128, 87, 79, 145, 123, 19, 162,
      111, 93, 191, 111, 187, 29, 243, 68, 205, 72, 140, 41, 228, 145,
      69, 122, 124, 24, 61, 106, 57, 136, 166, 97, 189, 213, 98, 147,
      189, 86, 56, 182, 0, 0, 0, 15, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 1, 101, 0>>}]
2. leveledjc_eqc:put(<0.8007.0>, <<98, 117, 99, 107, 101, 116, 49>>,
    <<2, 201, 141, 204, 220, 59, 44, 47, 23, 186, 96, 213, 119, 114,
      228, 125>>,
    <<53, 1, 0, 0, 0, 19, 131, 108, 0, 0, 0, 1, 104, 2, 100, 0, 5,
      105, 115, 97, 97, 99, 97, 1, 106, 0, 0, 0, 1, 0, 0, 1, 1, 1, 72,
      91, 51, 204, 93, 141, 134, 68, 135, 44, 79, 97, 32, 185, 231,
      207, 84, 127, 250, 100, 210, 95, 245, 171, 156, 134, 222, 162,
      47, 129, 81, 120, 132, 168, 55, 144, 18, 85, 77, 170, 49, 126,
      18, 189, 102, 97, 237, 249, 94, 128, 210, 250, 229, 70, 105, 152,
      31, 252, 224, 41, 145, 232, 23, 60, 58, 72, 178, 225, 10, 115,
      245, 230, 237, 114, 135, 88, 208, 125, 180, 210, 250, 76, 207,
      188, 96, 14, 32, 63, 88, 2, 254, 127, 79, 103, 22, 52, 250, 194,
      153, 168, 48, 166, 102, 210, 76, 247, 226, 137, 221, 24, 65, 76,
      66, 201, 130, 119, 55, 12, 129, 93, 131, 104, 83, 15, 233, 183,
      114, 223, 41, 229, 237, 12, 50, 219, 192, 184, 172, 77, 110, 176,
      103, 118, 10, 156, 113, 126, 52, 106, 144, 128, 125, 116, 115,
      11, 93, 149, 30, 180, 182, 68, 61, 186, 235, 113, 157, 211, 85, 
      50, 78, 24, 184, 222, 14, 147, 172, 232, 100, 98, 252, 201, 22,
      83, 174, 16, 79, 30, 151, 164, 144, 17, 132, 172, 44, 41, 222,
      216, 235, 108, 160, 84, 83, 201, 212, 42, 176, 140, 202, 50, 236,
      14, 222, 111, 143, 44, 54, 98, 7, 122, 164, 21, 218, 195, 45,
      189, 97, 70, 17, 194, 53, 12, 248, 115, 166, 82, 5, 7, 76, 145,
      169, 253, 120, 219, 239, 105, 76, 9, 152, 34, 25, 198, 253, 50,
      132, 12, 94, 55, 0, 0, 0, 15, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      1, 101, 0>>,
    [], o_rkv) ->
  ok