blp.BlpQuery().start.bql processing errors

[samrblackman]

Hi all,

I have used the blp.BlpQuery().start.bql syntax for a while now to pull lots of data. No issues.

I think since the lateest bloomberg update / office update, it breaks has strange performance. Sometimes it works but now routinely if I am looping through tickers and running a bq expression for each ticker and concatenating or something, it errors out with the "Error occurred during request processing" error number 5. Not sure what the issue is, I have reinstalled and updated my office tools/DAPI and so wondering if others are now aware of this and if it has something to do with a change to blpapi that needs to be updated here. Thanks!

[butterflywaltz]

About 10% of queries just started to fail randomly from Monday 27 Oct 2025.

In create_bql_query function, replace
values = {"expression": expression}
by
values = {"expression": expression, "clientContext": {"appName": "BQNT"}}

Should work again.

[cdnozzle]

tried the change you suggested still seem to get the error message 5. anything else i would need to take into consideration to make it work like before ?

[jnappa1]

I am getting the same issue as well, only a few of the queries work and am constantly receiving the processing error.

[jnappa1]

About 10% of queries just started to fail randomly from Monday 27 Oct 2025.

In create_bql_query function, replace values = {"expression": expression} by values = {"expression": expression, "clientContext": {"appName": "BQNT"}}

Should work again.

Tried this on my end even despite updating blpapi, does not work unfortunately.

Have also tested using bdp and bds, these work fine. This is an issue specifically with parsing bql expressions

[butterflywaltz]

@jnappa1 @cdnozzle I am unable to replicate error as the change I suggested is working well on my end. Do you guys have BQuant enabled? (i.e. does BQNT work on your terminal?)
Through some guesses, I found another app name that works for me "EXCEL", please try below:
values = {"expression": expression, "clientContext": {"appName": "EXCEL"}}

Updating blpapi or downgrading is unlikely having any effect. Because blpapi is just a messenger, the message is successfully send, it's the processing side on bloomberg server has changed, not sure what happened from an outsider. A reasonable guess is that a new server processing bql queries requiring app name has just been onboarded.

[jnappa1]

@jnappa1 @cdnozzle I am unable to replicate error as the change I suggested is working well on my end. Do you guys have BQuant enabled? (i.e. does BQNT work on your terminal?) Through some guesses, I found another app name that works for me "EXCEL", please try below: values = {"expression": expression, "clientContext": {"appName": "EXCEL"}}

Updating blpapi or downgrading is unlikely having any effect. Because blpapi is just a messenger, the message is successfully send, it's the processing side on bloomberg server has changed, not sure what happened from an outsider. A reasonable guess is that a new server processing bql queries requiring app name has just been onboarded.

Yeah I am fully using BQNT perfectly fine - all enabled on my end. The only change BB (that I know of) have made as of late is now the requirement that all scripts using blpapi now need to be registered using APRE and then authenticating with a unique key. I have tried this and it still doesn't work.

I will try your method again to see if that changes things.

[jnappa1]

@jnappa1 @cdnozzle I am unable to replicate error as the change I suggested is working well on my end. Do you guys have BQuant enabled? (i.e. does BQNT work on your terminal?) Through some guesses, I found another app name that works for me "EXCEL", please try below: values = {"expression": expression, "clientContext": {"appName": "EXCEL"}}
Updating blpapi or downgrading is unlikely having any effect. Because blpapi is just a messenger, the message is successfully send, it's the processing side on bloomberg server has changed, not sure what happened from an outsider. A reasonable guess is that a new server processing bql queries requiring app name has just been onboarded.

Yeah I am fully using BQNT perfectly fine - all enabled on my end. The only change BB (that I know of) have made as of late is now the requirement that all scripts using blpapi now need to be registered using APRE and then authenticating with a unique key. I have tried this and it still doesn't work.

I will try your method again to see if that changes things.

***Confirming EXCEL as app fixes this issue.

How did you generate the fix?

[butterflywaltz]

@jnappa1 I just read the BQuant python implementation...in your BQNT, try do below to get a hint of what context looking like:

from bql.common.client_context import ClientContextBuilder
context = ClientContextBuilder()
context.get_context()

I just used that app name and worked for me. And since BQL runs fine in Excel, and everything in Excel is executed via blpapi as well, Excel must have a valid app name of its own, then it's blind guess.

The APRE thing is new to me, you have any more details?

[vpsinghg]

@butterflywaltz Could you please share the repo and docs url from where you picked this snippet ?

[butterflywaltz]

@vpsinghg I haven’t seen any public repo and bql request is not documented in developer guide. All you can do is read source code of BB’s Bquant implementation.

[cdnozzle]

i do have access to Bqnt but for some reason using the app as excel does not seem to work. this is the snippet of code i am using. and i still get the same error.

from blp import blp
bquery = blp.BlpQuery().start()

fx = 'brl'
query = ("get(Rate(dates=range('-3M','0d'))) for(curvemembers('{} curncy', curve_type='fx', quote_type='Implied_Yield'))").format(fx)
values = {"expression": query, "clientContext": {"appName": "EXCEL"}}
fx_fwd = bquery.bql(values)

[butterflywaltz]

@cdnozzle that’s not how the proposed fix is meant to be applied. First locate the blp.py source file that you imported, and modify in the create_bql_query function as instructed in original reply.

[cdnozzle]

perfect ! that did the trick. thank you