Hi,
Imagine the following situation: in my data there is a high cardinality field, “a”, which can be also null. I use a hyperUnique aggregator on this field, but I’d also like to know the number of ingested lines where this field “a” was null. Currently my data also contains a field, “is_a_null”, which contains this information, and is ingested as a dimension in druid.
Optimally, I’d like to get rid of this field from my data, and use a dimensionspecs at ingestion time to transform “a”:
{
“type” : “extraction”,
“dimension” : “a”,
“outputName” : “is_a_null”,
“extractionFn” : {
“type” : “javascript”,
“function” : “function(str) { return str == null; }”
}
}
Is something like that possible?
Best regards,
Balazs