github.com/cockroachdb/cockroach@v20.2.0-alpha.1+incompatible/pkg/sql/opt/optgen/exprgen/testdata/fake (about)

     1  expr
     2  (FakeRel [])
     3  ----
     4  fake-rel
     5   ├── cardinality: [0 - 0]
     6   ├── stats: [rows=0]
     7   └── cost: 0.01
     8  
     9  expr
    10  (FakeRel
    11    [
    12      (OutputCols [ (NewColumn "a" "int") (NewColumn "b" "int") (NewColumn "c" "int")] )
    13      (NotNullCols "a,b")
    14      (Cardinality "-")
    15    ]
    16  )
    17  ----
    18  fake-rel
    19   ├── columns: a:1(int!null) b:2(int!null) c:3(int)
    20   ├── stats: [rows=0]
    21   └── cost: 0.01
    22  
    23  expr
    24  (FakeRel
    25    [
    26      (OutputCols [ (NewColumn "a" "int") (NewColumn "b" "int") (NewColumn "c" "int")] )
    27      (Cardinality "5 - 1000")
    28      (Stats `[
    29        {
    30          "columns": ["a"],
    31          "distinct_count": 100,
    32          "null_count": 0, 
    33          "row_count": 100, 
    34          "created_at": "2018-01-01 1:00:00.00000+00:00"
    35        },
    36        {
    37          "columns": ["b"],
    38          "distinct_count": 20,
    39          "null_count": 5, 
    40          "row_count": 100, 
    41          "created_at": "2018-01-01 1:00:00.00000+00:00"
    42        }
    43      ]`)
    44    ]
    45  )
    46  ----
    47  fake-rel
    48   ├── columns: a:1(int) b:2(int) c:3(int)
    49   ├── cardinality: [5 - 1000]
    50   ├── stats: [rows=100, distinct(1)=100, null(1)=0, distinct(2)=20, null(2)=5]
    51   └── cost: 0.01
    52  
    53  # Verify that newer stats are preferred.
    54  expr
    55  (FakeRel
    56    [
    57      (OutputCols [ (NewColumn "a" "int") (NewColumn "b" "int") (NewColumn "c" "int")] )
    58      (Cardinality "-")
    59      (Stats `[
    60        {
    61          "columns": ["a"],
    62          "distinct_count": 100,
    63          "null_count": 0, 
    64          "row_count": 100, 
    65          "created_at": "2018-01-01 1:00:00.00000+00:00"
    66        },
    67        {
    68          "columns": ["a"],
    69          "distinct_count": 110,
    70          "null_count": 0, 
    71          "row_count": 110, 
    72          "created_at": "2018-01-02 1:00:00.00000+00:00"
    73        },
    74        {
    75          "columns": ["b"],
    76          "distinct_count": 20,
    77          "null_count": 5, 
    78          "row_count": 100, 
    79          "created_at": "2018-01-01 1:00:00.00000+00:00"
    80        },
    81        {
    82          "columns": ["b"],
    83          "distinct_count": 22,
    84          "null_count": 5, 
    85          "row_count": 120, 
    86          "created_at": "2018-01-03 1:00:00.00000+00:00"
    87        }
    88      ]`)
    89    ]
    90  )
    91  ----
    92  fake-rel
    93   ├── columns: a:1(int) b:2(int) c:3(int)
    94   ├── stats: [rows=120, distinct(1)=110, null(1)=0, distinct(2)=22, null(2)=5]
    95   └── cost: 0.01