internal: remove fastrand

This package is no longer necessary, as in `math/rand/v2` the
`rand.Uint32` function is equivalent.

internal/arenaskl/skl.go

@@ -45,13 +45,13 @@ package arenaskl // import "github.com/cockroachdb/pebble/internal/arenaskl"
 
 import (
  "math"
+ "math/rand/v2"
  "runtime"
  "sync/atomic"
  "unsafe"
 
  "github.com/cockroachdb/errors"
  "github.com/cockroachdb/pebble/internal/base"
- "github.com/cockroachdb/pebble/internal/fastrand"
 )
 
 const (
@@ -337,7 +337,7 @@ func (s *Skiplist) newNode(
 }
 
 func (s *Skiplist) randomHeight() uint32 {
- rnd := fastrand.Uint32()
+ rnd := rand.Uint32()
 
  h := uint32(1)
  for h < maxHeight && rnd <= probabilities[h] {

internal/invariants/utils.go

@@ -4,10 +4,10 @@
 
 package invariants
 
-import "github.com/cockroachdb/pebble/internal/fastrand"
+import "math/rand/v2"
 
 // Sometimes returns true percent% of the time if we were built with the
 // "invariants" of "race" build tags
 func Sometimes(percent int) bool {
- return Enabled && fastrand.Uint32()%100 < uint32(percent)
+ return Enabled && rand.Uint32N(100) < uint32(percent)
 }

iterator.go

@@ -8,13 +8,13 @@ import (
  "bytes"
  "context"
  "io"
+ "math/rand/v2"
  "sync"
  "unsafe"
 
  "github.com/cockroachdb/errors"
  "github.com/cockroachdb/pebble/internal/base"
  "github.com/cockroachdb/pebble/internal/bytealloc"
- "github.com/cockroachdb/pebble/internal/fastrand"
  "github.com/cockroachdb/pebble/internal/humanize"
  "github.com/cockroachdb/pebble/internal/invariants"
  "github.com/cockroachdb/pebble/internal/keyspan"
@@ -810,14 +810,14 @@ func (i *Iterator) maybeSampleRead() {
  }
  bytesRead := uint64(len(i.key) + i.value.Len())
  for i.readSampling.bytesUntilReadSampling < bytesRead {
- i.readSampling.bytesUntilReadSampling += uint64(fastrand.Uint32n(2 * uint32(samplingPeriod)))
+ i.readSampling.bytesUntilReadSampling += uint64(rand.Uint32N(2 * uint32(samplingPeriod)))
  // The block below tries to adjust for the case where this is the
  // first read in a newly-opened iterator. As bytesUntilReadSampling
  // starts off at zero, we don't want to sample the first read of
  // every newly-opened iterator, but we do want to sample some of them.
  if !i.readSampling.initialSamplePassed {
  i.readSampling.initialSamplePassed = true
- if fastrand.Uint32n(uint32(i.readSampling.bytesUntilReadSampling)) > uint32(bytesRead) {
+ if rand.Uint32N(uint32(i.readSampling.bytesUntilReadSampling)) > uint32(bytesRead) {
  continue
  }
  }