github.com/cockroachdb/pebble@v0.0.0-20231214172447-ab4952c5f87b/sstable/testdata/size_estimate (about)

     1  # Sequence of ops which tests all of the code paths in the size_estimate type.
     2  
     3  init 1
     4  ----
     5  success
     6  
     7  # Empty size should be 1
     8  size
     9  ----
    10  1
    11  
    12  # There's a single inflight entry, so the size should be 4.
    13  add_inflight 4
    14  ----
    15  4
    16  
    17  num_inflight_entries
    18  ----
    19  1
    20  
    21  num_entries
    22  ----
    23  1
    24  
    25  # Compression ratio defaults to 1, so the size of the inflight entry fully
    26  # counts towards size.
    27  size
    28  ----
    29  4
    30  
    31  # After compression, entry only had a size of 3. The total size is therefore
    32  # 3, since this is the first entry. The max estimated size is 4 since we
    33  # ensure that it is monotonically non decreasing.
    34  entry_written 3 4
    35  ----
    36  4
    37  
    38  num_entries
    39  ----
    40  1
    41  
    42  # There should be 0 inflight entries once the previous entry has been written.
    43  num_inflight_entries
    44  ----
    45  0
    46  
    47  # Compression ratio is 0.75 at this point. The total size is 3, and the inflight
    48  # size is 5, so that returned size is uint64(3 + 0.75*5) = uint64(6.75).
    49  add_inflight 5
    50  ----
    51  6
    52  
    53  num_entries
    54  ----
    55  2
    56  
    57  # We don't clear the empty size, so even after clearing a size of 1 is returned.
    58  clear
    59  ----
    60  1
    61  
    62  # Test writing multiple inflight entries.
    63  add_inflight 4
    64  ----
    65  4
    66  
    67  add_inflight 5
    68  ----
    69  9
    70  
    71  num_entries
    72  ----
    73  2
    74  
    75  num_inflight_entries
    76  ----
    77  2
    78  
    79  # First inflight entry written. The entry didn't get compressed. The total size
    80  # now is less than 9, but the max estimated size should still be 9.
    81  entry_written 4 4
    82  ----
    83  9
    84  
    85  num_entries
    86  ----
    87  2
    88  
    89  num_inflight_entries
    90  ----
    91  1
    92  
    93  # At this point, inflightSize is 13, the totalSize is 4. The compression ratio
    94  # is 1. So, the returned size should be 17.
    95  add_inflight 8
    96  ----
    97  17
    98  
    99  # One entry has been written.
   100  num_written_entries
   101  ----
   102  1
   103  
   104  # The inflight entry had a size of 5, but the entry added had a size of 3
   105  # because of compression/size estimation. The compression ratio is (4+3)/(4+5)
   106  # = 0.77 at this point. The inflightSize is 8. The true size is 7+8*0.77 =
   107  # 13.22, but the maxEstimatedSize is returned.
   108  entry_written 7 5
   109  ----
   110  17
   111  
   112  # The inflight size is 0, and the total size is 11.
   113  entry_written 11 8
   114  ----
   115  17
   116  
   117  num_written_entries
   118  ----
   119  3
   120  
   121  # The compression ratio is (4+3+4)/(4+5+8)=0.647, and the inflight size is 20,
   122  # 20*0.64 = 12.94, so the total size is uint64(12.94 + 11)
   123  add_inflight 20
   124  ----
   125  23
   126  
   127  num_inflight_entries
   128  ----
   129  1
   130  
   131  # We can write an entry, which increases the written size from 11 to 19, but
   132  # it might not have an inflightSize, because it was never inflight. In such a
   133  # case, the numInflightEntries, shouldn't be decreased.
   134  entry_written 19 0
   135  ----
   136  31
   137  
   138  num_inflight_entries
   139  ----
   140  1
   141  
   142  num_written_entries
   143  ----
   144  4