MarketDefinition is null on initial marketChangeMessage from StreamingAPI

[JetB]

Hi

I'm in the process of testing the StreamingAPI. What I can't get my head round is that on subscribing to Market changes, the first market change message I get back (before Json parsing) has null for the MarketDefinition field which I need to extract out the eventId for example.

Here's a sample of the output (I'm just testing for football for now) - I've curtailed it for the purposes of this post but the key issue is there is no output for the market definition.

{"op":"mcm","id":2,"initialClk":"uhqyrcuBBcIa5Paeg QW8GrfMnIYF","clk":"AAAAAAAA","conflateMs":180000, "heartbeatMs":5000,"pt":1588101985103,"ct":"SUB_IM AGE","mc":[{"id":"1.170291929","rc":[{"bdatb":[[2,11.07,2.35],[0,15.28,1.75],[1,13.66,1.78]],"bdatl":[[1,26,19.11],[2,27.66,18.08]....,"img":true}

The documentation says that the MarketDefinition "is sent in full (but only if it has changed)" so I would expect this to be returned in the first mcm response.

Anyone have any ideas of what could be going wrong here?

[LiamP]

Judging by the conflate I assume you are using the delayed key?

[JetB]

yes, that's correct - is that the explanation?

[JetB]

actually, I realise the reason for the above issue was that I hadn't included EX_MARKET_DEF in the MarketDataFilter fields list. This is needed to return the MarketDefinition