performance improvement for time format (#1118)

Author: chanxuehong

connection.go

@@ -245,44 +245,10 @@ func (mc *mysqlConn) interpolateParams(query string, args []driver.Value) (strin
 ifv.IsZero(){
 buf=append(buf, "'0000-00-00'"...)
  } else{
-v:=v.In(mc.cfg.Loc)
-v=v.Add(time.Nanosecond*500) // To round under microsecond
-year:=v.Year()
-year100:=year/100
-year1:=year%100
-month:=v.Month()
-day:=v.Day()
-hour:=v.Hour()
-minute:=v.Minute()
-second:=v.Second()
-micro:=v.Nanosecond() /1000
-
-buf=append(buf, []byte{
-'\'',
-digits10[year100], digits01[year100],
-digits10[year1], digits01[year1],
-'-',
-digits10[month], digits01[month],
-'-',
-digits10[day], digits01[day],
-' ',
-digits10[hour], digits01[hour],
-':',
-digits10[minute], digits01[minute],
-':',
-digits10[second], digits01[second],
- }...)
-
-ifmicro!=0{
-micro10000:=micro/10000
-micro100:=micro/100%100
-micro1:=micro%100
-buf=append(buf, []byte{
-'.',
-digits10[micro10000], digits01[micro10000],
-digits10[micro100], digits01[micro100],
-digits10[micro1], digits01[micro1],
- }...)
+buf=append(buf, '\'')
+buf, err=appendDateTime(buf, v.In(mc.cfg.Loc))
+iferr!=nil{
+return"", err
  }
 buf=append(buf, '\'')
  }

packets.go

@@ -1116,7 +1116,10 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error{
 ifv.IsZero(){
 b=append(b, "0000-00-00"...)
  } else{
-b=v.In(mc.cfg.Loc).AppendFormat(b, timeFormat)
+b, err=appendDateTime(b, v.In(mc.cfg.Loc))
+iferr!=nil{
+returnerr
+ }
  }
 
 paramValues=appendLengthEncodedInteger(paramValues,

utils.go

@@ -276,6 +276,55 @@ func parseBinaryDateTime(num uint64, data []byte, loc *time.Location) (driver.Va
 returnnil, fmt.Errorf("invalid DATETIME packet length %d", num)
 }
 
+funcappendDateTime(buf []byte, t time.Time) ([]byte, error){
+nsec:=t.Nanosecond()
+// to round under microsecond
+ifnsec%1000>=500{// save half of time.Time.Add calls
+t=t.Add(500*time.Nanosecond)
+nsec=t.Nanosecond()
+ }
+year, month, day:=t.Date()
+hour, min, sec:=t.Clock()
+micro:=nsec/1000
+
+ifyear<1||year>9999{
+returnbuf, errors.New("year is not in the range [1, 9999]: "+strconv.Itoa(year)) // use errors.New instead of fmt.Errorf to avoid year escape to heap
+ }
+year100:=year/100
+year1:=year%100
+
+varlocalBuf [26]byte// does not escape
+localBuf[0], localBuf[1], localBuf[2], localBuf[3] =digits10[year100], digits01[year100], digits10[year1], digits01[year1]
+localBuf[4] ='-'
+localBuf[5], localBuf[6] =digits10[month], digits01[month]
+localBuf[7] ='-'
+localBuf[8], localBuf[9] =digits10[day], digits01[day]
+
+ifhour==0&&min==0&&sec==0&&micro==0{
+returnappend(buf, localBuf[:10]...), nil
+ }
+
+localBuf[10] =' '
+localBuf[11], localBuf[12] =digits10[hour], digits01[hour]
+localBuf[13] =':'
+localBuf[14], localBuf[15] =digits10[min], digits01[min]
+localBuf[16] =':'
+localBuf[17], localBuf[18] =digits10[sec], digits01[sec]
+
+ifmicro==0{
+returnappend(buf, localBuf[:19]...), nil
+ }
+
+micro10000:=micro/10000
+micro100:= (micro/100) %100
+micro1:=micro%100
+localBuf[19] ='.'
+localBuf[20], localBuf[21], localBuf[22], localBuf[23], localBuf[24], localBuf[25] =
+digits10[micro10000], digits01[micro10000], digits10[micro100], digits01[micro100], digits10[micro1], digits01[micro1]
+
+returnappend(buf, localBuf[:]...), nil
+}
+
 // zeroDateTime is used in formatBinaryDateTime to avoid an allocation
 // if the DATE or DATETIME has the zero value.
 // It must never be changed.

utils_test.go

@@ -293,6 +293,78 @@ func TestIsolationLevelMapping(t *testing.T){
  }
 }
 
+funcTestAppendDateTime(t*testing.T){
+tests:= []struct{
+t time.Time
+strstring
+ }{
+{
+t: time.Date(2020, 05, 30, 0, 0, 0, 0, time.UTC),
+str: "2020-05-30",
+ },
+{
+t: time.Date(2020, 05, 30, 22, 0, 0, 0, time.UTC),
+str: "2020-05-30 22:00:00",
+ },
+{
+t: time.Date(2020, 05, 30, 22, 33, 0, 0, time.UTC),
+str: "2020-05-30 22:33:00",
+ },
+{
+t: time.Date(2020, 05, 30, 22, 33, 44, 0, time.UTC),
+str: "2020-05-30 22:33:44",
+ },
+{
+t: time.Date(2020, 05, 30, 22, 33, 44, 550000000, time.UTC),
+str: "2020-05-30 22:33:44.550000",
+ },
+{
+t: time.Date(2020, 05, 30, 22, 33, 44, 550000499, time.UTC),
+str: "2020-05-30 22:33:44.550000",
+ },
+{
+t: time.Date(2020, 05, 30, 22, 33, 44, 550000500, time.UTC),
+str: "2020-05-30 22:33:44.550001",
+ },
+{
+t: time.Date(2020, 05, 30, 22, 33, 44, 550000567, time.UTC),
+str: "2020-05-30 22:33:44.550001",
+ },
+{
+t: time.Date(2020, 05, 30, 22, 33, 44, 999999567, time.UTC),
+str: "2020-05-30 22:33:45",
+ },
+ }
+for_, v:=rangetests{
+buf:=make([]byte, 0, 32)
+buf, _=appendDateTime(buf, v.t)
+ifstr:=string(buf); str!=v.str{
+t.Errorf("appendDateTime(%v), have: %s, want: %s", v.t, str, v.str)
+return
+ }
+ }
+
+// year out of range
+{
+v:=time.Date(0, 1, 1, 0, 0, 0, 0, time.UTC)
+buf:=make([]byte, 0, 32)
+_, err:=appendDateTime(buf, v)
+iferr==nil{
+t.Error("want an error")
+return
+ }
+ }
+{
+v:=time.Date(10000, 1, 1, 0, 0, 0, 0, time.UTC)
+buf:=make([]byte, 0, 32)
+_, err:=appendDateTime(buf, v)
+iferr==nil{
+t.Error("want an error")
+return
+ }
+ }
+}
+
 funcTestParseDateTime(t*testing.T){
 cases:= []struct{
 namestring