Need help to create alert for a huge number of events

[Gene]

Dear Splunkers, Hello. I am new to Splunk and have task to create alert for following scenario:

Each minute we receive about 100K events and need to find out events where field value is greater than 180.
Also we have 2 eval fields (current value and previous value)

After each event - current_value = previous_value +(-)1 based on value (greater or less than 180). Also when end of file is reached - next file should start with values of current and previous results.

I have created following search but it doesn't work well:

index=OurIndex

| eval alertType = ""
| eval threshold = 180
| eval severity = "low"
| eval maxLevel = 5
| eval alertLevel = 1
| eval clearLevel = 0

| eval startTime = round(relative_time(_time, "-0s@s"))
| eval processedTime = now()
| eval metric = "dl_dmax"
| eval metricValue = dl_dmax
| streamstats current=f window=1 last(dl_dmax) as lastDmax, last(stateLevel) as lastStateLevel by _time
| eval stateLevel = if(isnull(lastStateLevel), 0, lastStateLevel)
| eval lastLevel = if(lastDmax>threshold, case(stateLevel<maxLevel, stateLevel+1, stateLevel==maxLevel, maxLevel), case(stateLevel!=0, stateLevel-1, stateLevel=0, 0))
| eval stateLevel = if(metricValue>threshold, case(lastLevel<maxLevel, lastLevel+1, lastLevel==maxLevel, maxLevel), case(lastLevel!=0, lastLevel-1, lastLevel=0, 0))
| table snmpid, objectId, objectName, objectType,  alertLevel, lastLevel, stateLevel

 For now stateLevel is never greater than 2 and lastLevel is not greater than 1. Can you please advise on how to modify my search to make it working?

Thanks in advance!

[Gene]

Hello all, I will update my question with example
we have events
id| sessionID | dl_max (numeric value with time to process event)| other not needed fields
num | num| num

what I want to achieve after search

SessionID | dl_max | threshold | lastLevel | stateLevel
1                  | 100  | 180 | 0 | 0

2                  | 190 | 180 | 0 | 1
3                   | 200 | 180 |1 | 2

4                  | 220 | 180 | 2| 3
5                  |160 | 180 |3 | 2

I would really appreciate your help.