github.com/cockroachdb/pebble@v1.1.2/testdata/iterator_read_sampling (about)

     1  # Test with overlapping keys across levels, should pick top level to compact after allowed-seeks goes to 0
     2  # Verify that Iterator.First(), Iterator.SeekGE() and Iterator.Next() call maybe sample read.
     3  define auto-compactions=off
     4  L0
     5    a.SET.4:4
     6  L1
     7    a.SET.3:3
     8  L2
     9    d.SET.2:2
    10  L3
    11    d.SET.1:1
    12  ----
    13  0.0:
    14    000004:[a#4,SET-a#4,SET]
    15  1:
    16    000005:[a#3,SET-a#3,SET]
    17  2:
    18    000006:[d#2,SET-d#2,SET]
    19  3:
    20    000007:[d#1,SET-d#1,SET]
    21  
    22  set allowed-seeks=2
    23  ----
    24  
    25  
    26  iter
    27  first
    28  ----
    29  a: (4, .)
    30  
    31  iter-read-compactions
    32  ----
    33  (none)
    34  
    35  iter
    36  first
    37  ----
    38  a: (4, .)
    39  
    40  iter-read-compactions
    41  ----
    42  (level: 0, start: a, end: a)
    43  
    44  read-compactions
    45  ----
    46  (none)
    47  
    48  close-iter
    49  ----
    50  
    51  read-compactions
    52  ----
    53  (level: 0, start: a, end: a)
    54  
    55  iter
    56  seek-ge d
    57  ----
    58  d: (2, .)
    59  
    60  iter
    61  prev
    62  ----
    63  a: (4, .)
    64  
    65  iter
    66  next
    67  ----
    68  d: (2, .)
    69  
    70  iter-read-compactions
    71  ----
    72  (level: 2, start: d, end: d)
    73  
    74  close-iter
    75  ----
    76  
    77  read-compactions
    78  ----
    79  (level: 0, start: a, end: a)
    80  (level: 2, start: d, end: d)
    81  
    82  
    83  
    84  # Verify that Iterator.Last(), Iterator.SeekLT() and Iterator.Prev() call maybe sample read.
    85  define auto-compactions=off
    86  L0
    87    a.SET.4:4
    88    c.SET.8:8
    89  L1
    90    a.SET.3:3
    91    c.SET.9:9
    92  L2
    93    d.SET.2:2
    94    l.SET.7:7
    95  L3
    96    d.SET.1:1
    97    l.SET.8:8
    98  ----
    99  0.0:
   100    000004:[a#4,SET-c#8,SET]
   101  1:
   102    000005:[a#3,SET-c#9,SET]
   103  2:
   104    000006:[d#2,SET-l#7,SET]
   105  3:
   106    000007:[d#1,SET-l#8,SET]
   107  
   108  set allowed-seeks=2
   109  ----
   110  
   111  
   112  iter
   113  last
   114  ----
   115  l: (8, .)
   116  
   117  iter-read-compactions
   118  ----
   119  (none)
   120  
   121  iter
   122  last
   123  ----
   124  l: (8, .)
   125  
   126  iter-read-compactions
   127  ----
   128  (level: 2, start: d, end: l)
   129  
   130  read-compactions
   131  ----
   132  (none)
   133  
   134  close-iter
   135  ----
   136  
   137  read-compactions
   138  ----
   139  (level: 2, start: d, end: l)
   140  
   141  iter
   142  seek-lt d
   143  ----
   144  c: (9, .)
   145  
   146  iter
   147  next
   148  ----
   149  d: (2, .)
   150  
   151  iter
   152  prev
   153  ----
   154  c: (9, .)
   155  
   156  iter-read-compactions
   157  ----
   158  (level: 0, start: a, end: c)
   159  
   160  close-iter
   161  ----
   162  
   163  read-compactions
   164  ----
   165  (level: 2, start: d, end: l)
   166  (level: 0, start: a, end: c)
   167  
   168  
   169  # For Iterator.Last(), Iterator.SeekLT() and Iterator.Prev(), if the key is the first key of the file or
   170  # the only key, sampling skips it because the iterator has already moved past it.
   171  define auto-compactions=off
   172  L0
   173    a.SET.4:4
   174  L1
   175    a.SET.3:3
   176  L2
   177    d.SET.2:2
   178  L3
   179    d.SET.1:1
   180  ----
   181  0.0:
   182    000004:[a#4,SET-a#4,SET]
   183  1:
   184    000005:[a#3,SET-a#3,SET]
   185  2:
   186    000006:[d#2,SET-d#2,SET]
   187  3:
   188    000007:[d#1,SET-d#1,SET]
   189  
   190  set allowed-seeks=2
   191  ----
   192  
   193  
   194  iter
   195  last
   196  ----
   197  d: (2, .)
   198  
   199  iter-read-compactions
   200  ----
   201  (none)
   202  
   203  iter
   204  last
   205  ----
   206  d: (2, .)
   207  
   208  iter-read-compactions
   209  ----
   210  (none)
   211  
   212  read-compactions
   213  ----
   214  (none)
   215  
   216  close-iter
   217  ----
   218  
   219  read-compactions
   220  ----
   221  (none)
   222  
   223  iter
   224  seek-lt d
   225  ----
   226  a: (4, .)
   227  
   228  iter
   229  next
   230  ----
   231  d: (2, .)
   232  
   233  iter
   234  prev
   235  ----
   236  a: (4, .)
   237  
   238  iter-read-compactions
   239  ----
   240  (none)
   241  
   242  close-iter
   243  ----
   244  
   245  read-compactions
   246  ----
   247  (none)
   248  
   249  
   250  
   251  
   252  # Test with no overlapping keys across levels, should not pick any compaction
   253  define auto-compactions=off
   254  L0
   255    a.SET.4:4
   256  L1
   257    b.SET.3:3
   258  L2
   259    c.SET.2:2
   260  L3
   261    d.SET.1:1
   262  ----
   263  0.0:
   264    000004:[a#4,SET-a#4,SET]
   265  1:
   266    000005:[b#3,SET-b#3,SET]
   267  2:
   268    000006:[c#2,SET-c#2,SET]
   269  3:
   270    000007:[d#1,SET-d#1,SET]
   271  
   272  set allowed-seeks=3
   273  ----
   274  
   275  iter
   276  first
   277  ----
   278  a: (4, .)
   279  
   280  iter
   281  first
   282  ----
   283  a: (4, .)
   284  
   285  iter
   286  first
   287  ----
   288  a: (4, .)
   289  
   290  iter-read-compactions
   291  ----
   292  (none)
   293  
   294  close-iter
   295  ----
   296  
   297  read-compactions
   298  ----
   299  (none)
   300  
   301  # Test to see if the allowedSeeks associated with a file
   302  # is reset once it hits 0.
   303  define auto-compactions=off
   304  L0
   305    a.SET.4:4
   306    c.SET.8:8
   307  L1
   308    a.SET.3:3
   309    c.SET.9:9
   310  L2
   311    d.SET.2:2
   312    l.SET.7:7
   313  L3
   314    d.SET.1:1
   315    l.SET.8:8
   316  ----
   317  0.0:
   318    000004:[a#4,SET-c#8,SET]
   319  1:
   320    000005:[a#3,SET-c#9,SET]
   321  2:
   322    000006:[d#2,SET-l#7,SET]
   323  3:
   324    000007:[d#1,SET-l#8,SET]
   325  
   326  set allowed-seeks=1
   327  ----
   328  
   329  iter
   330  last
   331  ----
   332  l: (8, .)
   333  
   334  iter-read-compactions
   335  ----
   336  (level: 2, start: d, end: l)
   337  
   338  close-iter
   339  ----
   340  
   341  read-compactions
   342  ----
   343  (level: 2, start: d, end: l)
   344  
   345  # The allowedSeeks on this file should have been reset.
   346  # Since the value of allowedSeeks determined
   347  # by the code is 100, we check if allowed-seeks has been
   348  # reset to 100.
   349  show allowed-seeks=(000006,)
   350  ----
   351  100