<symbol>@bookTicker (futures) order book updateId is not consistent

Websocket
1

Hello,
I try to use @bookTicker in my project.
In documentation Binance API Documentation web socket push data:

{
  "e":"bookTicker",         // event type
  "u":400900217,            // order book updateId
  "E": 1568014460893,       // event time
  "T": 1568014460891,       // transaction time
  "s":"BNBUSDT",            // symbol
  "b":"25.35190000",        // best bid price
  "B":"31.21000000",        // best bid qty
  "a":"25.36520000",        // best ask price
  "A":"40.66000000"         // best ask qty
}
This data have field - "u" - order book updateId. 
In documentation written - Update Speed: Real-time.

**Question:** Why field value of "u" is not consistent. For example: i get u = 1690098908783, next data u = 1690098908888. I expected  1690098908783 > 1690098908784. Web socket does not give all the changes of order book?

P.S.: I'm trying to match trades with the order book, and I have a problem that the order book update is much less frequent than the trades.

Thanks
2

Unlike SPOT, the update id in the futures exchange is shared between all symbols. Therefore the "u" property will not be incremental as an update does not necessarily mean the order book you are subscribed to had a state change.

1 Like
3

Thanks