Lightning: Skip apply ioworkers when seek(0, io.SeekCurrent) (pingcap#57454) (pingcap#57930)

ti-chi-bot · web-flow · commit 772377222d94 · 2024-12-04T06:32:56.000Z
close pingcap#57413
diff --git a/br/pkg/lightning/mydump/reader.go b/br/pkg/lightning/mydump/reader.go
@@ -187,7 +187,8 @@ func (pr PooledReader) Read(p []byte) (n int, err error) {
 
 // Seek implements io.Seeker
 func (pr PooledReader) Seek(offset int64, whence int) (int64, error) {
-	if pr.ioWorkers != nil {
+	// Seek(0, io.SeekCurrent) is used to get the current offset, which will not cause any Disk I/O.
+	if pr.ioWorkers != nil && !(offset == 0 && whence == io.SeekCurrent) {
 		w := pr.ioWorkers.Apply()
 		defer pr.ioWorkers.Recycle(w)
 	}

Original file line number	Diff line number	Diff line change
`@@ -187,7 +187,8 @@ func (pr PooledReader) Read(p []byte) (n int, err error) {`
`187`	`187`
`188`	`188`	`// Seek implements io.Seeker`
`189`	`189`	`func (pr PooledReader) Seek(offset int64, whence int) (int64, error) {`
`190`		`- if pr.ioWorkers != nil {`
	`190`	`+ // Seek(0, io.SeekCurrent) is used to get the current offset, which will not cause any Disk I/O.`
	`191`	`+ if pr.ioWorkers != nil && !(offset == 0 && whence == io.SeekCurrent) {`
`191`	`192`	`w := pr.ioWorkers.Apply()`
`192`	`193`	`defer pr.ioWorkers.Recycle(w)`
`193`	`194`	`}`