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133 lines
3.6 KiB
Go

10 years ago
package main
import (
"bufio"
"fmt"
"os"
"sync"
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"time"
)
var chunk_id struct {
sync.Mutex
val int
}
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// type chunk represents a grouping of redis statements to be sent to a redis
// server.
type chunk struct {
id int
vals []value
t time.Time
}
// creates a new chunk of a given size, automatically assigning it a
// monotomically increasing id.
func newChunk(size int) *chunk {
chunk_id.Lock()
defer chunk_id.Unlock()
chunk_id.val++
return &chunk{id: chunk_id.val, vals: make([]value, 0, size)}
}
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// write out a chunk's statements onto a bufio.Writer. After sending all
// statements onto the bufio.Writer, reads from the provided channel of
// responses N times, where N is the number of statements originally sent.
func (c *chunk) send(w *bufio.Writer, responses chan maybe) *sendResult {
stats := new(sendResult)
stats.start()
defer stats.stop()
for _, v := range c.vals {
n, err := v.Write(w)
if err != nil {
fmt.Fprintf(os.Stderr, "error writing a statement: %v\n", err)
}
stats.byteSize += n
}
if err := w.Flush(); err != nil {
fmt.Fprintf(os.Stderr, "error flushing statement buffer: %v\n", err)
}
for _, request := range c.vals {
response, ok := <-responses
if !ok {
// we get here when the response channel closes too early
fmt.Fprintf(os.Stderr, "error reading redis response stream: response chan closed early")
return stats
}
stats.accumulate(request, response)
}
return stats
}
// -----------------------------------------------------------------------------
type sendResult struct {
read int // number of statement sread on the incoming statement stream
errors int // number of error responses seen on the redis response stream
replies int // number of reply responses seen on the redis response stream
byteSize int // number of bytes sent
elapsed time.Duration // time taken to send requests and receive responses from redis
paused time.Duration // sleep time inserted
startTime time.Time
}
func (s *sendResult) start() {
s.startTime = time.Now()
}
func (s *sendResult) stop() {
s.elapsed = time.Since(s.startTime)
}
func (s *sendResult) avg() time.Duration {
if s.read == 0 {
fmt.Fprintln(os.Stderr, "for some reason, we tried to divide by zero on sendResult.avg. we recovered, though.")
return 100 * time.Microsecond
}
return time.Duration(int64(s.elapsed) / int64(s.read))
}
func (s *sendResult) log() {
if !options.chunkInfo {
return
}
fmt.Printf("errors: %d replies: %d total: %d sent: %d elapsed: %v avg: %v size: %v\n", s.errors, s.replies, s.errors+s.replies, s.read, s.elapsed, s.avg(), s.byteSize)
}
func (s *sendResult) nextSize() int {
target := int(int64(chunk_target) / int64(s.avg()))
return min(target, chunk_max, 2*s.read)
}
func (s *sendResult) accumulate(request value, response maybe) {
s.read++
if response.ok() {
switch r := response.val().(type) {
case ErrorVal:
// these errors are errors reported from redis. e.g., if you
// try to do something like delete a key that doesn't exist or
// send an invalid command to redis
if options.verbose {
fmt.Fprintf(os.Stderr, "%q -> %q\n", request, response.val())
} else {
fmt.Fprintf(os.Stderr, "%q\n", r)
}
s.errors++
default:
if options.verbose {
fmt.Fprintf(os.Stdout, "%q -> %q\n", request, response.val())
}
s.replies++
}
} else {
// we get here when we encounter an error in the response stream.
// That is, the response stream contains bytes that are not valid
// in the redis protocol.
fmt.Fprintf(os.Stderr, "ResponseError: %v\n", response.err())
}
}