From 6b0b6ff8f8acff721cb0d1b6ae302913a910a277 Mon Sep 17 00:00:00 2001
From: a631807682 <631807682@qq.com>
Date: Sun, 14 Aug 2022 21:56:52 +0800
Subject: [PATCH] chore[ci skip]: improve code comments

---
 prepare_stmt.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/prepare_stmt.go b/prepare_stmt.go
index 456204b8..3934bb97 100644
--- a/prepare_stmt.go
+++ b/prepare_stmt.go
@@ -79,8 +79,9 @@ func (db *PreparedStmtDB) prepare(ctx context.Context, conn ConnPool, isTransact
 	// prepare completed
 	defer close(cacheStmt.prepared)
 
-	// Reason why cannot lock conn.PrepareContext (suppose the maxopen is 1).
-	// 1. g1 begin tx, now `db.ConnPool` db.numOpen == 1
+	// Reason why cannot lock conn.PrepareContext
+	// suppose the maxopen is 1, g1 is creating record and g2 is querying record.
+	// 1. g1 begin tx, g1 is requeued because of waiting for the system call, now `db.ConnPool` db.numOpen == 1.
 	// 2. g2 select lock `conn.PrepareContext(ctx, query)`, now db.numOpen == db.maxOpen , wait for release.
 	// 3. g1 tx exec insert, wait for unlock `conn.PrepareContext(ctx, query)` to finish tx and release.
 	stmt, err := conn.PrepareContext(ctx, query)