added query event in dummy event handler

[axfor]

added more query event

• onQueryEvent query event include(create user,drop user,create index event,etd.)

[lance6716]

why do we need it?

[axfor]

Based on mysql.Position adds SavePos and Force fields

I think queryEvent contains multiple sub-events, pos save logic, and it is up to the end-user event to decide whether to save or not

---

func (h *DummyEventHandler) OnQueryEvent(header *replication.EventHeader, stmt ast.StmtNode, pos *Position, e *replication.QueryEvent) error { 
         //....
        pos.SavePos =true
	return nil
}

---

Of course, it can also be handled uniformly in the main loop of canal/sync.go events.

https://github.com/axfor/go-mysql/blob/feature-axx/canal/sync.go#L161

func (c *Canal) startSyncer() (*replication.BinlogStreamer, error) { 
        //....
       for _, stmt := range stmts {
		nodes := parseDDLStmt(stmt)
		if len(nodes) > 0 {
		      // OnDDL
		} else {
			err := c.handleQueryEvent(ev.Header, stmt, posInfo, e)
			if err != nil {
				c.cfg.Logger.Errorf("handle query event err %v", err)
			} else {
				savePos = true   // for save pos
				force = true   // for save pos
			}
               }
              //....
       } 
      //....
}

[lance6716]

it is up to the end-user event to decide whether to save or not

I think it's more obvious to use return value to do it.

OnQueryEvent(ev *replication.BinlogEvent, e *replication.QueryEvent, stmt ast.StmtNode, pos mysql.Position) (savePos bool, force bool, err error)

[axfor]

Ok, I'll modify it

[lance6716]

Please use named return in this interface, or explain what's the meaning of two bools in comments. So users of this library will understand when they implement this interface.

[lance6716]

Suggested change

	if err != nil {
	return savePos, force, errors.Trace(err)
	}
	return savePos, force, nil
	return savePos, force, errors.Trace(err)