[horse racing] [historical data] Why are there multiple files for a day?

[fdsafds]

(1) Why are the multiple files for a day? Meaning, one "main" and the ones with "1.". Why not have one single file?

(2) What does each line represent in the both types of the files (".1" and without it)? Information about ... what? A change of the positions of the horses over time?

(3) What does market mean in this context?

[BetfairDeveloperProgram]

(1) Why are the multiple files for a day? Meaning, one "main" and the ones with "1.". Why not have one single file?

The file structure is designed to represent the Betfair Exchange market offering i.e. on any given day there are multiple events containing one or more markets.

(2) What does each line represent in the both types of the files (".1" and without it)? Information about ... what? A change of the positions of the horses over time?

Each line represents a new update MarketChangeMessage (mcm). This may be a change to any of the fields within either the

MarketDefinition - (Fields containing details of the market - new market definition is published if any of these field change
RunnerDefinition - Details of the selections in the betting market
Market change - Changes to market prices, runners
Runner Change - a list of changes to runners

You can find the full fields and data specification via https://historicdata.betfair.com/Bet...cification.pdf

(3) What does market mean in this context?

Market means a Betfair Exchange betting market. For example https://www.betfair.com/exchange/plus/horse-racing/market/1.201486745?nodeId=31621466

[fdsafds]

Market means a Betfair Exchange betting market. For example https://www.betfair.com/exchange/plus/horse-racing/market/1.201486745?nodeId=31621466

Betfair Exchange betting market -- implies one market. Right? How can then there be multiple markets in the historical data? What do those different markets refer to?
Are they different Exchanges?

[BetfairDeveloperProgram]

Betfair Exchange betting market -- implies one market. Right? How can then there be multiple markets in the historical data? What do those different markets refer to?
Are they different Exchanges?

No, they are different markets that exist within a single event. For example, for horse racing, an event has multiple races (markets) within a single meeting (event).

For football, a single event (Man Utd vs Liverpool) has a number of betting makets (Match Odds, Correct Score, Under/Over 1.5 goals etc)

[fdsafds]

No, they are different markets that exist within a single event. For example, for horse racing, an event has multiple races (markets) within a single meeting (event).

For football, a single event (Man Utd vs Liverpool) has a number of betting makets (Match Odds, Correct Score, Under/Over 1.5 goals etc)

Alright. For horse racing, one market = one race, right?


I'm interested, for now, in "markettype = "WIN" only, if this relevant.

[BetfairDeveloperProgram]

Yes, for horse racing, one market is for a single race assuming you are looking at "markettype = "WIN" only.

[fdsafds]

"marketStart" - is when a race physically starts, right?


What does the very last line in a market file always represent?
Is it a market change right before/after the winner has finished? Or right before/after the 2rd and 3rd horses have finished? Or maybe right before the latest horse has finished?

[BetfairDeveloperProgram]

"marketStart" - is when a race physically starts, right?

This is the scheduled start time of the race, the actual start time may differ from the scheduled time.

What does the very last line in a market file always represent?
Is it a market change right before/after the winner has finished? Or right before/after the 2rd and 3rd horses have finished? Or maybe right before the latest horse has finished?

The last market change message in the file represent the final marketDefinition following market settlement. This represents how the market was settled - specifically which selections were settled as LOSER or WINNER. See an example below:

{"op":"mcm","clk":"6295482797","pt":1658939236252, "mc":[{"id":"1.201407932","marketDefinition":{"bspMarket ":true,"turnInPlayEnabled":true,"persistenceEnable d":true,"marketBaseRate":5.0,"eventId":"31615204", "eventTypeId":"7","numberOfWinners":1,"bettingType ":"ODDS","marketType":"WIN","marketTime":"2022-07-27T16:20:00.000Z","suspendTime":"2022-07-27T16:20:00.000Z","bspReconciled":true,"complete": true,"inPlay":true,"crossMatching":true,"runnersVo idable":false,"numberOfActiveRunners":0,"betDelay" :1,"status":"CLOSED","settledTime":"2022-07-27T16:24:05.000Z","runners":[{"adjustmentFactor":3.85,"status":"REMOVED","sortP riority":1,"removalDate":"2022-07-26T09:16:30.000Z","id":18154247,"name":"Lord Rapscallion"},{"adjustmentFactor":1.4,"status":"RE MOVED","sortPriority":2,"removalDate":"2022-07-27T06:41:02.000Z","id":35400152,"name":"Prince Of Bel Lir"},{"adjustmentFactor":16.66,"status":"LOSER"," sortPriority":3,"bsp":6.54,"id":31428753,"name":"T he Attorney"},{"adjustmentFactor":14.31,"status":"LOS ER","sortPriority":4,"bsp":5.66,"id":25182441,"nam e":"Mums Tipple"},{"adjustmentFactor":11.32,"status":"LOSER ","sortPriority":5,"bsp":9.03,"id":41822110,"name" :"Stockpyle"},{"adjustmentFactor":8.11,"status":"L OSER","sortPriority":6,"bsp":13.5,"id":40034960,"n ame":"Amor Vincit Omnia"},{"adjustmentFactor":7.78,"status":"LOSER", "sortPriority":7,"bsp":16.06,"id":29547710,"name": "Wild Lion"},{"adjustmentFactor":5.4,"status":"LOSER","s ortPriority":8,"bsp":10.61,"id":25785690,"name":"S tunning Beauty"},{"adjustmentFactor":5.26,"status":"LOSER" ,"sortPriority":9,"bsp":24.37,"id":25842152,"name" :"Dance Fever"},{"adjustmentFactor":4.23,"status":"LOSER", "sortPriority":10,"bsp":17.21,"id":32879539,"name" :"Titan Rock"},{"adjustmentFactor":4.05,"status":"LOSER"," sortPriority":11,"bsp":21.0,"id":21022912,"name":" Asad"},{"adjustmentFactor":4.05,"status":"LOSER"," sortPriority":12,"bsp":33.86,"id":39554797,"name": "Windseeker"},{"adjustmentFactor":3.35,"status":"W INNER","sortPriority":13,"bsp":25.14,"id":21124918 ,"name":"Lyndon B"},{"adjustmentFactor":3.24,"status":"LOSER","sor tPriority":14,"bsp":24.83,"id":29110994,"name":"To ussarok"},{"adjustmentFactor":3.04,"status":"LOSER ","sortPriority":15,"bsp":44.0,"id":166899,"name": "Bowman"},{"adjustmentFactor":2.86,"status":"LOSER ","sortPriority":16,"bsp":45.32,"id":31101807,"nam e":"Farasi Lane"},{"adjustmentFactor":2.7,"status":"LOSER","s ortPriority":17,"bsp":32.0,"id":10739864,"name":"A nimal Instinct"},{"adjustmentFactor":1.77,"status":"LOSE R","sortPriority":18,"bsp":71.51,"id":43898372,"na me":"Princess Olly"},{"adjustmentFactor":1.21,"status":"LOSER"," sortPriority":19,"bsp":131.34,"id":39113753,"name" :"Dig Two"},{"adjustmentFactor":0.57,"status":"LOSER","s ortPriority":20,"bsp":155.19,"id":24420618,"name": "Milltown Star"}],"regulators":["MR_INT"],"venue":"Goodwood","countryCode":"GB","discountAl lowed":true,"timezone":"Europe/London","openDate":"2022-07-27T12:50:00.000Z","version":4669730987,"name":"7f Hcap","eventName":"Goodwood 27th Jul"}}]}

[fdsafds]

Got it, thanks.