A long time ago, someone stated in this Data and Contet Support topic: https://forums.iqfeed.net/index.cfm?page=topic&topicID=2402 that market indexes and stats are updated frequently, perhaps as often as tick-by-tick. I could swear I've read somewhere on the web that many of the famous indexes (such as SPX) have their vlaues updated only as often as every 15 seconds. But anyway...

For those with realtime subscriptions who write their own code with the TCP IQFeed API, what is the best way to consume indexes and market stats, if we want the quickest available updates? Obviously the Market Summary snapshot call wouldn't be ideal if, for instance, the Russell "exchange" summary file for security type Index is updated on DTN servers every 5 minutes.

1. Can indexes and market stats actually be consumed via an L1 Watch API call? (clearly most of the dynamic fields such as those related to bid and ask would not apply, which is why I ask)

1a. If an L1 feed is the way to go, are there any special values for any of the dynamic fields (such as "Message Contents") which woudl have any specific or unusual meanings for indexes or market stats?

2. Do people instead request streaming interval bars for these with an interval set as low as applicable (with a floor of 1 second)? If the old thread I referenced is correct about tick-by-tick frequency, this wouldn't take advantage of the "realtime" subscription.

2a. Many market stats such as "TRIN" lend themselves to line charts rather than bars... In this caseI guess one might simply use "last" from the OHLC values and just discard the other 3 "price" fields? (moot if streaming bars wouldn't be used for live index/market stat requests)

2a. I can grab historical bars off-hours, so I'm not worried about the "8/180" day restriction for second intervals which aren't a multiple of 20; I'd mainly be consuming only the current day's "trades". But, as a good citizen in the DTN ecosystm, is there an upper limit to the number of 1-second streaming bars calls I can make (currrent day only) or is this simply included in the (base) 500-symbol limit? (moot if streaming bars wouldn't be used for live index/market stat requests)

OR

3. If there is a better API call to stream real time data for indexes and/or market stats not covered above, just mention that and ignore the other numberd questions

---

-Mark D. Valor
Edited by mkvalor on Dec 1, 2022 at 12:53 AM
Edited by mkvalor on Dec 1, 2022 at 12:54 AM
Edited by mkvalor on Dec 1, 2022 at 01:04 AM

Just stream the symbol as L1 like all the other symbols. Pull out the relevant fields and ignore the rest.

Since they are lighter load, not much to worry about. They do add to your overall symbol count.

You can reduce the dynamic fields down to what ever you normally use. Otherwise, you'll need a different TCP connection to use a different set of dynamic fields.

mkvalor,

1. Can indexes and market stats actually be consumed via an L1 Watch API call? Yes, they behave just as any other symbol would. You are correct that fields like Bid and Ask will have no meaning, so you can omit them from your message using the S,SELECT UPDATE FIELDS message as Stargazer suggested. (see http://www.iqfeed.net/dev/api/docs//DynamicFieldsets.cfm)

1A. are there any special values for any of the dynamic fields (such as "Message Contents") Not that I know of, but I'll double-check.

2. 2. Do people instead request streaming interval bars for these with an interval set as low as applicable (with a floor of 1 second)? If the old thread I referenced is correct about tick-by-tick frequency, this wouldn't take advantage of the "realtime" subscription.

You are correct that this wouldn't be very efficient - if an indicator updates once a second, then there's no advantage to streaming interval bars versus a Level 1 follow. Some people don't need tick-by-tick precision, though, so I wouldn't be surprised to learn that some people only collect the data minute-by-minute.

I guess one might simply use "last" from the OHLC values and just discard the other 3 "price" fields? See above: most market stats use only Last, and other fields are left blank, or have placeholder values.

is there an upper limit to the number of 1-second streaming bars calls I can make (currrent day only) or is this simply included in the (base) 500-symbol limit? Included in your symbol limit.

---

Sincerely,
Gary Stephen
DTN IQFeed Implementation Support Specialist