fix default fetch.min.bytes to 1, (#565)

eaglexiang · web-flow · commit 1d5a83b2bb0e · 2020-12-04T11:36:49.000-08:00
following official document. (https://kafka.apache.org/documentation/#fetch.min.bytes)
diff --git a/reader.go b/reader.go
@@ -24,6 +24,13 @@ const (
 	defaultCommitRetries = 3
 )
 
+const (
+	// defaultFetchMinBytes of 1 byte means that fetch requests are answered as
+	// soon as a single byte of data is available or the fetch request times out
+	// waiting for data to arrive.
+	defaultFetchMinBytes = 1
+)
+
 var (
 	errOnlyAvailableWithGroup = errors.New("unavailable when GroupID is not set")
 	errNotAvailableWithGroup  = errors.New("unavailable when GroupID is set")
@@ -581,7 +588,7 @@ func NewReader(config ReaderConfig) *Reader {
 	}
 
 	if config.MinBytes == 0 {
-		config.MinBytes = config.MaxBytes
+		config.MinBytes = defaultFetchMinBytes
 	}
 
 	if config.MaxWait == 0 {

Original file line number	Diff line number	Diff line change
`@@ -24,6 +24,13 @@ const (`
`24`	`24`	`defaultCommitRetries = 3`
`25`	`25`	`)`
`26`	`26`
	`27`	`+const (`
	`28`	`+ // defaultFetchMinBytes of 1 byte means that fetch requests are answered as`
	`29`	`+ // soon as a single byte of data is available or the fetch request times out`
	`30`	`+ // waiting for data to arrive.`
	`31`	`+ defaultFetchMinBytes = 1`
	`32`	`+)`
	`33`	`+`
`27`	`34`	`var (`
`28`	`35`	`errOnlyAvailableWithGroup = errors.New("unavailable when GroupID is not set")`
`29`	`36`	`errNotAvailableWithGroup = errors.New("unavailable when GroupID is set")`
`@@ -581,7 +588,7 @@ func NewReader(config ReaderConfig) *Reader {`
`581`	`588`	`}`
`582`	`589`
`583`	`590`	`if config.MinBytes == 0 {`
`584`		`- config.MinBytes = config.MaxBytes`
	`591`	`+ config.MinBytes = defaultFetchMinBytes`
`585`	`592`	`}`
`586`	`593`
`587`	`594`	`if config.MaxWait == 0 {`