topic Search query using spath and mvexpand on multi-value nested JSON doesn't scale in Splunk Search

Search query using spath and mvexpand on multi-value nested JSON doesn't scale

sharad06 — Thu, 26 Oct 2017 02:23:26 GMT

Hi Splunk Experts,

I am sending events to Splunk Enterprise in the following nested JSON format:

{
     compliance:     Compliance Unknown,    
     ctupdate:   hostinfo,  
     host_properties:   [
            {
             name:   _times,    
              since:     1508907165,    
             value:  last_onsite    
            },  
            {
              name:  compliance_state,  
               since:    1508268020,    
               value:    N/A    
            },  
            {
              name:  engine_seen_packet,    
               since:    1508907165,    
               value:    Yes    
            },  
            {
               name:     guest_corporate_state, 
               since:    1508268020,    
               value:    N/A    
            },  
            {
             name:   linux_operating_system,    
             since:  1508907165,    
             value:  2.0.2  
            },  
            {
             name:   online,    
             since:  1508907165,    
             value:  online_multivalue1
            },  
                {
             name:   online,    
             since:  1508907165,    
             value:  online_multivalue2
            },
                {
             name:   online,    
             since:  1508907165,    
             value:  online_multivalue3
            },
            {
             name:   ssh_open_port, 
             since:  1508959259,    
             value:  0  
            },
            {
             name:   va_netfunc,    
             since:  1508959247,    
             value:  Linux Desktop/Server   
            }   
    ]   
     ip:     192.168.1.17,  
     tenant_id:  acd1034578ef
}

I want to create a dashboard that would go over all such events and display a pie-chart with online values seen so far. To achieve this, I've been using the following query:

`ct_hostinfo` `get_sourcetypes`
| spath output=prop_name path=host_properties{}.name
| spath output=prop_val path=host_properties{}.value
| eval prop_key_val=mvzip(prop_name, prop_val, "---")
| mvexpand prop_key_val
| eval prop_key_val=split(prop_key_val, "---")
| eval prop_name=mvindex(prop_key_val, 0)
| eval prop_val=mvindex(prop_key_val, 1)
| search prop_name=online
| stats count by prop_val

The above query does its work but it doesn't scale. If I let my dashboard collect data for over ~5k events, I start seeing the following error:

command.mvexpand: output will be truncated at 1300 results due to excessive memory usage. Memory threshold of 500MB as configured in limits.conf / [mvexpand] / max_mem_usage_mb has been reached.

I would like to know if I can somehow scale the above search query so that it can handle greater number of events. Would I need to defined field extractions etc. in transforms.conf/props.conf? I don't know much about field extraction configs.

I would be very grateful, if someone can suggest me a better query or field extractions.

Thanks.

Re: Search query using spath and mvexpand on multi-value nested JSON doesn't scale

DalJeanis — Mon, 30 Oct 2017 01:51:24 GMT

You are carrying along a ton of fields when you mvexpand your records. That calculates to over 300K per record. You only need prop_key_val at that point, right?

Two fields commands, immediately before the mvexpand, should put you up to millions of records possible.

 | eval prop_key_val=mvzip(prop_name, prop_val, "---")
 | fields prop_key_val
 | fields - _*
 | mvexpand prop_key_val

Looking deeper, you only want ONE of the values for prop_name=online, so you don't need the mvexpand at all. You need mvfilter.

Try this against your existing search for a small time number of records. It should get the same results. If not, then adjust the mvfilter test until it does. (Adjust case sensitivity, like() vs match(), and so on)

`ct_hostinfo` `get_sourcetypes`
 | spath output=prop_name path=host_properties{}.name
 | spath output=prop_val path=host_properties{}.value
 | eval prop_key_val=mvzip(prop_name, prop_val, "---")
 | eval prop_key_val=mvfilter( like(prop_key_val,"online%") 
 | mvexpand prop_key_val
 | eval prop_val=mvindex(split(prop_key_val, "---"), 1)
 | stats count by prop_val

Re: Search query using spath and mvexpand on multi-value nested JSON doesn't scale

sharad06 — Tue, 07 Nov 2017 20:05:39 GMT

Hi Dal,

I tried your suggestion to remove internal fields (fields - _*). But it doesn't work 😞

It's always returning 'No results found'.