// This method never blocks. It'll buffer writes until they fill the buffer then drop the on the
// floor and let the background goroutine replay from the WAL
func (self *WriteBuffer) Write(request *protocol.Request) {
self.shardLastRequestNumber[request.GetShardId()] = request.GetRequestNumber()
select {
case self.writes <- request:
log.Debug("Buffering %d:%d for %s", request.GetRequestNumber(), request.GetShardId(), self.writerInfo)
return
default:
select {
case self.stoppedWrites <- *request.RequestNumber:
return
default:
return
}
}
}
func (self *WriteBuffer) write(request *protocol.Request) {
attempts := 0
for {
self.shardIds[*request.ShardId] = true
err := self.writer.Write(request)
if err == nil {
requestNumber := request.RequestNumber
if requestNumber == nil {
return
}
self.shardCommitedRequestNumber[request.GetShardId()] = *requestNumber
log.Debug("Commiting %d:%d for %s", request.GetRequestNumber(), request.GetShardId(), self.writerInfo)
self.wal.Commit(*requestNumber, self.serverId)
return
}
if attempts%100 == 0 {
log.Error("%s: WriteBuffer: error on write to server %d: %s", self.writerInfo, self.serverId, err)
}
attempts += 1
// backoff happens in the writer, just sleep for a small fixed amount of time before retrying
time.Sleep(time.Millisecond * 100)
}
}