You posted in the Elasticsearch category vs Logstash so was assuming you were talking about ingest pipelines.
In Logstash you will use the Grok Filter with the same pattern I posted above.
filter {
grok {
match => { "message": "conn=10 op=221996 RESULT err=0 tag=101 nentries=1 wtime=0.000062880 optime=0.000082472 etime=0.000143846" }
}
}