Max value along with timestamp retrieval question

[ace-han]

Say, I have below time series for metric cpu.load_1min

t0	t1	t2	t3	t4	t5	t6	t7	t8	t9
0	10	90	20	80	30	70	40	60	50

I wanna extract the highest value along with its timestamp. in above case it's <t2, 90>. I also want the timestamp to be the exact timestamp without downsampling.

And I'm talking about generating a 3-month timespan report for over 10 thousand servers. So querying them all back and then do the max operation myself is really not my option.

I found that /api/query or /api/query/exp could not do it

Please help me out, thx.

[johann8384]

Well, if you do the gexp you can do max(${query}) and get the max value, I think we implemented Max, if not, adding it would not be terribly hard.

In either case, you're still going to be querying three months of data and calculating the max, it will involve a little less network traffic to do it server side.

For doing long queries, I recommend using Splicer (github.com/turn/splicer) it will shard your query into 1 hour blocks and run them in parallel against the cluster of TSD nodes. I use it with 10x Docker containers running RO mode OpenTSDB on each HDFS Datanode/HBase RegionServer. Splicer also sends the queries to the node which hosts the region which also reduces the network traffic. Once it has retrieved the data it will cache the 1 hour blocks in Redis. This greatly improves the amount of time required to run long queries in cases where most of the data was previously queried.

[ace-han]

@johann8384 for the gexp you referred to, I kinda not getting it work. In the doc, I found below two endpoints highestMax and highestCurrent, and sadly their behaviors are like below

http://opentsdb/api/query/gexp?start=3n-ago&exp=highestMax(max:network.pkts_in{host=s1|s2|s3}, 2) result looks

and detail in one of the array

The return result is about the top n time series with full list of values including the max value respectively, not a simple array with <max_ts, max_value>.

It's not sth more like what I expected in below format (not with a bunch of values, just the max, min or avg value during that specific period)

[
{"host": "s1", "max_value_ts": "tsX", "max_value": "max_value_s1"},
{"host": "s2", "max_value_ts": "tsY", "max_value": "max_value_s2"},
]

Or am I missing anything on the doc? Or just the doc just lack of examples of how to use gexp.

Looking forward to your help

[opsun]

https://github.com/OpenTSDB/opentsdb/pull/1048

I have been fixed this issue.

[IDerr]

Hi @ace-han if your question has been answered can you close this issue please ?

Thanks

[mancubus77]

Facing same issue on 2.3 Instead of MAX value, TSDB return set of datapoints. http://opentsdb/api/query/gexp?start=4h-ago&exp=highestMax(max:if.percent.peak.stat\{tid=xx,dir=*,target=*\},2)

    "dps": {
      "1516852800": 17.200000762939453,
      "1516853700": 18.350000381469727,
      "1516854600": 18.5,
      "1516855500": 19.31999969482422,
      "1516856400": 17.479999542236328,
      "1516857300": 16.450000762939453,
      "1516860900": 22.56999969482422,
      "1516861800": 22.8799991607666
    }