How to create a search to detect if no increase in the count of fields?

[jakeoftrades]

hi,

can anyone help me how should I query the counts of kafka_datatype  of those stream_type which Im going to set an alert if there will be no increase within  3 hours within only a time period of time 7am-8pm 

I have this query :

index="pcg_p4_datataservices_prod" sourcetype="be:monitoring-services"
| setfields a=a
| rex "^[^\|\n]*\|\s+(?P<kafka_datatype>\w+)\s+\-\s+(?P<kafka_count>.+)"
| search kafka_datatype IN (PRODUCED, CONSUMED)
| search stream_type IN (Datascore_Compress, Datascore_Decompress, Eservices_Eload, Eservices_Ebills)
| eval service_details=stream_type
| timechart span=3h limit=0 sum(kafka_count) by service_details

I tried to add in the query for the earliest/latest (as -180m I guess for 3hrs) but not showing any result that Im aiming to set it  to detect that if for 3 hours if no increase in the count of kafka_datatype of those stream_type which Im going to set the alert:

index="pcg_p4_datataservices_prod" sourcetype="be:monitoring-services"
earliest=-180m
latest=now
| setfields a=a
| rex "^[^\|\n]*\|\s+(?P<kafka_datatype>\w+)\s+\-\s+(?P<kafka_count>.+)"
| search kafka_datatype IN (PRODUCED, CONSUMED)
| search stream_type IN (Datascore_Compress, Datascore_Decompress, Eservices_Eload, Eservices_Ebills)
| eval service_details=stream_type
| timechart span=3h limit=0 sum(kafka_count) by service_details