github.com/pingcap/badger@v1.5.1-0.20230103063557-828f39b09b6d/cache/sketch_test.go (about)

     1  package cache
     2  
     3  import (
     4  	"testing"
     5  )
     6  
     7  func TestSketch(t *testing.T) {
     8  	defer func() {
     9  		if r := recover(); r == nil {
    10  			t.Fatal("no panic with bad param numCounters")
    11  		}
    12  	}()
    13  	s := newCmSketch(5)
    14  	if s.mask != 7 {
    15  		t.Fatal("not rounding up to next power of 2")
    16  	}
    17  	newCmSketch(0)
    18  }
    19  
    20  func TestSketchIncrement(t *testing.T) {
    21  	s := newCmSketch(16)
    22  	s.Increment(1)
    23  	s.Increment(5)
    24  	s.Increment(9)
    25  	for i := 0; i < cmDepth; i++ {
    26  		if s.rows[i].string() != s.rows[0].string() {
    27  			break
    28  		}
    29  		if i == cmDepth-1 {
    30  			t.Fatal("identical rows, bad seeding")
    31  		}
    32  	}
    33  }
    34  
    35  func TestSketchEstimate(t *testing.T) {
    36  	s := newCmSketch(16)
    37  	s.Increment(1)
    38  	s.Increment(1)
    39  	if s.Estimate(1) != 2 {
    40  		t.Fatal("estimate should be 2")
    41  	}
    42  	if s.Estimate(0) != 0 {
    43  		t.Fatal("estimate should be 0")
    44  	}
    45  }
    46  
    47  func TestSketchReset(t *testing.T) {
    48  	s := newCmSketch(16)
    49  	s.Increment(1)
    50  	s.Increment(1)
    51  	s.Increment(1)
    52  	s.Increment(1)
    53  	s.Reset()
    54  	if s.Estimate(1) != 2 {
    55  		t.Fatal("reset failed, estimate should be 2")
    56  	}
    57  }
    58  
    59  func TestSketchClear(t *testing.T) {
    60  	s := newCmSketch(16)
    61  	for i := 0; i < 16; i++ {
    62  		s.Increment(uint64(i))
    63  	}
    64  	s.Clear()
    65  	for i := 0; i < 16; i++ {
    66  		if s.Estimate(uint64(i)) != 0 {
    67  			t.Fatal("clear failed")
    68  		}
    69  	}
    70  }
    71  
    72  func BenchmarkSketchIncrement(b *testing.B) {
    73  	s := newCmSketch(16)
    74  	b.SetBytes(1)
    75  	for n := 0; n < b.N; n++ {
    76  		s.Increment(1)
    77  	}
    78  }
    79  
    80  func BenchmarkSketchEstimate(b *testing.B) {
    81  	s := newCmSketch(16)
    82  	s.Increment(1)
    83  	b.SetBytes(1)
    84  	for n := 0; n < b.N; n++ {
    85  		s.Estimate(1)
    86  	}
    87  }