From b0940b663f8a08cdcbba5613756b997b0d0982cf Mon Sep 17 00:00:00 2001
From: INADA Naoki <songofacandy@gmail.com>
Date: Tue, 4 Dec 2018 00:24:18 +0900
Subject: [PATCH 1/2] Reset internal buffer when rows.Close() is called.

Fixes #903
---
 buffer.go | 6 ++++++
 rows.go   | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/buffer.go b/buffer.go
index 19486bd6f..964920358 100644
--- a/buffer.go
+++ b/buffer.go
@@ -37,6 +37,12 @@ func newBuffer(nc net.Conn) buffer {
 	}
 }
 
+func (b *buffer) reset() {
+	b.buf = make([]byte, defaultBufSize)
+	b.idx = 0
+	b.length = 0
+}
+
 // fill reads into the buffer until at least _need_ bytes are in it
 func (b *buffer) fill(need int) error {
 	n := b.length
diff --git a/rows.go b/rows.go
index d3b1e2822..08727f999 100644
--- a/rows.go
+++ b/rows.go
@@ -111,6 +111,10 @@ func (rows *mysqlRows) Close() (err error) {
 		return err
 	}
 
+	// We can't reuse receive buffer when rows.Close() is called.
+	// See https://github.com/golang/go/commit/651ddbdb5056ded455f47f9c494c67b389622a47
+	mc.buf.reset()
+
 	// Remove unread packets from stream
 	if !rows.rs.done {
 		err = mc.readUntilEOF()

From 30ff57936e26e6d356506eb55bf74b174cf6f513 Mon Sep 17 00:00:00 2001
From: INADA Naoki <songofacandy@gmail.com>
Date: Tue, 4 Dec 2018 10:15:23 +0900
Subject: [PATCH 2/2] fix

---
 buffer.go | 21 ++++++++++++++++++---
 rows.go   |  2 +-
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/buffer.go b/buffer.go
index 964920358..d9ae7f52e 100644
--- a/buffer.go
+++ b/buffer.go
@@ -37,10 +37,25 @@ func newBuffer(nc net.Conn) buffer {
 	}
 }
 
-func (b *buffer) reset() {
-	b.buf = make([]byte, defaultBufSize)
+// discard trims b.buf[:b.idx] to prohibit it reused.
+//
+// This is required by Rows.Close().
+// See https://github.com/golang/go/commit/651ddbdb5056ded455f47f9c494c67b389622a47
+func (b *buffer) discard() {
+	if len(b.buf)-b.idx >= defaultBufSize {
+		b.buf = b.buf[b.idx:]
+		b.idx = 0
+		return
+	}
+
+	bufSize := defaultBufSize
+	if bufSize < b.length {
+		bufSize = b.length
+	}
+	newBuf := make([]byte, bufSize)
+	copy(newBuf, b.buf[b.idx:b.idx+b.length])
+	b.buf = newBuf
 	b.idx = 0
-	b.length = 0
 }
 
 // fill reads into the buffer until at least _need_ bytes are in it
diff --git a/rows.go b/rows.go
index 08727f999..5fc6f23e4 100644
--- a/rows.go
+++ b/rows.go
@@ -113,7 +113,7 @@ func (rows *mysqlRows) Close() (err error) {
 
 	// We can't reuse receive buffer when rows.Close() is called.
 	// See https://github.com/golang/go/commit/651ddbdb5056ded455f47f9c494c67b389622a47
-	mc.buf.reset()
+	mc.buf.discard()
 
 	// Remove unread packets from stream
 	if !rows.rs.done {