From 9226e584461480fccb81b38324275a1bc7420289 Mon Sep 17 00:00:00 2001
From: sylzd <sylzd@qq.com>
Date: Wed, 21 Oct 2020 14:37:06 +0800
Subject: [PATCH] Improve for_select_default_busy (pingcap/dumpling#169)

* fix for_select_default_busy
---
 dumpling/v4/export/writer_util.go | 43 ++++++++++++++-----------------
 1 file changed, 20 insertions(+), 23 deletions(-)

diff --git a/dumpling/v4/export/writer_util.go b/dumpling/v4/export/writer_util.go
index acfa3e10..6edf9fcc 100644
--- a/dumpling/v4/export/writer_util.go
+++ b/dumpling/v4/export/writer_util.go
@@ -193,21 +193,19 @@ func WriteInsert(pCtx context.Context, tblIR TableDataIR, w storage.Writer, file
 				bf.WriteString(";\n")
 			}
 			if bf.Len() >= lengthLimit {
-				wp.input <- bf
-				bf = pool.Get().(*bytes.Buffer)
-				if bfCap := bf.Cap(); bfCap < lengthLimit {
-					bf.Grow(lengthLimit - bfCap)
+				select {
+				case <-pCtx.Done():
+					return pCtx.Err()
+				case err := <-wp.errCh:
+					return err
+				case wp.input <- bf:
+					bf = pool.Get().(*bytes.Buffer)
+					if bfCap := bf.Cap(); bfCap < lengthLimit {
+						bf.Grow(lengthLimit - bfCap)
+					}
 				}
 			}
 
-			select {
-			case <-pCtx.Done():
-				return pCtx.Err()
-			case err := <-wp.errCh:
-				return err
-			default:
-			}
-
 			if shouldSwitch {
 				break
 			}
@@ -288,21 +286,20 @@ func WriteInsertInCsv(pCtx context.Context, tblIR TableDataIR, w storage.Writer,
 
 		bf.WriteByte('\n')
 		if bf.Len() >= lengthLimit {
-			wp.input <- bf
-			bf = pool.Get().(*bytes.Buffer)
-			if bfCap := bf.Cap(); bfCap < lengthLimit {
-				bf.Grow(lengthLimit - bfCap)
+			select {
+			case <-pCtx.Done():
+				return pCtx.Err()
+			case err := <-wp.errCh:
+				return err
+			case wp.input <- bf:
+				bf = pool.Get().(*bytes.Buffer)
+				if bfCap := bf.Cap(); bfCap < lengthLimit {
+					bf.Grow(lengthLimit - bfCap)
+				}
 			}
 		}
 
 		fileRowIter.Next()
-		select {
-		case <-pCtx.Done():
-			return pCtx.Err()
-		case err := <-wp.errCh:
-			return err
-		default:
-		}
 		if wp.ShouldSwitchFile() {
 			break
 		}