influxdata / influxdata/influxdb-java
Incorrect long values returned due to json to java conversion
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Description
I am having a problem with bad long values being returned due to the conversion to double that happens when all JSON numeric values are stored as Doubles.
This came up first when trying to get back time values as nanoseconds instead of rfc3339 string values. But we need to store very large long values in other fields as well. The application here is scientific instruments, so numerical errors are pretty high priority problems when we are looking at data storage.
From looking around, it does not look like there is a good way to intercept the JSON and convert to Long instead of Double... but maybe I am missing something? I would like to find some way to get these values returned as Long instead of Double. Maybe a different converter? I would appreciate any suggestions or workarounds.
Here is a snippet that recreates the problem:
long lval = 1485370052974000001L;
BatchPoints batchPoints = BatchPoints
.database(dbName)
.tag("async", "true")
.retentionPolicy("autogen")
.consistency(ConsistencyLevel.ALL)
.build();
Point point = Point.measurement("testProblems")
.time(innano, TimeUnit.NANOSECONDS)
.addField("double", 3.14)
.addField("long", lval)
.build();
batchPoints.point(point);
influxDB.write(batchPoints);
Series series0 = result.getResults().get(0).getSeries().get(0);
List<String> cols = series0.getColumns();
List<Object> val0 = series0.getValues().get(0);
Object outlval_obj = val0.get(cols.indexOf("long"));
if (outlval_obj instanceof Double)
{
long outlval = ((Double)outlval_obj).longValue();
if (outlval != lval)
{
System.err.println("Got bad lval back as double [" + (outlval_obj) + "] -> " + outlval + " != " + lval);
}
}
Here is a gist with more code and outputs:
https://gist.github.com/ghmegan/4ed652c8c8dbaf18976c6f5f4c0c6b55
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Research direction
Start with the provided BatchPoints/Point reproduction and the linked gist, then trace the JSON result conversion that turns the long field into a Double. Determine how large integer values can round-trip without loss, and verify completion by confirming the reproduced value is returned exactly rather than as a corrupted Double.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- java
- Domain
- database
- Issue type
- Bug
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100