capistrant commented on issue #10042:
URL: https://github.com/apache/druid/issues/10042#issuecomment-675682218
@gianm It appears to be essentially the same stack trace.
@leerho since the sketch is only an aggregated value and not a persisted
value in the segment, I only know how to access it as base64. If theres a tool
out there to decode I will gladly do that, but I figured I'd talk with you
before going down that route.
recap: Druid 0.18 broker queries a druid 0.15 historical. So it would
violate Lee's point above stating the only guarantee is that older sketches can
be read by newer code and not the opposite as we have in this case.
Base64 result from the historical node:
```JSON
[
{
"timestamp": "2020-08-05T01:00:00.000Z",
"result": {
"historical_version_count_2week": "AQMDAAA6zJPXi9u+uHa0Uw==",
"historical_version_count_1week": "AQMDAAA6zJPXi9u+uHa0Uw=="
}
}
]
```
The query:
```JSON
{
"queryType": "timeseries",
"dataSource": {
"type": "table",
"name": "druidMigration.cluster-metrics"
},
"granularity": "all",
"intervals": [
"2020-08-05T00:00:00/2020-08-19T00:00:00"
],
"aggregations": [
{
"type": "filtered",
"filter": {
"type": "and",
"fields": [
{
"type": "interval",
"dimension": "__time",
"intervals": [
"2020-08-05T00:00:00/2020-08-12T00:00:00"
]
},
{
"type": "selector",
"dimension": "service",
"value": "druid/historical"
}
]
},
"aggregator": {
"type": "thetaSketch",
"fieldName": "version",
"name": "historical_version_count_2week"
}
},
{
"type": "filtered",
"filter": {
"type": "and",
"fields": [
{
"type": "interval",
"dimension": "__time",
"intervals": [
"2020-08-12T00:00:00/2020-08-19T00:00:00"
]
},
{
"type": "selector",
"dimension": "service",
"value": "druid/historical"
}
]
},
"aggregator": {
"type": "thetaSketch",
"fieldName": "version",
"name": "historical_version_count_1week"
}
}
],
"postAggregations": [
{
"type": "arithmetic",
"name": "(historical_version_count_2week -
historical_version_count_1week)",
"fn": "-",
"fields": [
{
"type": "thetaSketchEstimate",
"name": "historical_version_count_2week",
"field": {
"type": "fieldAccess",
"fieldName": "historical_version_count_2week"
}
},
{
"type": "thetaSketchEstimate",
"name": "historical_version_count_1week",
"field": {
"type": "fieldAccess",
"fieldName": "historical_version_count_1week"
}
}
]
}
],
"filter": null,
"context": {
"priority": 2,
"timeout": 60000,
"useCache": false
}
}
```
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
