jackye1995 commented on code in PR #9717:
URL: https://github.com/apache/iceberg/pull/9717#discussion_r1496277335
##########
open-api/rest-catalog-open-api.yaml:
##########
@@ -3324,6 +3348,184 @@ components:
type: integer
format: int64
+ BooleanTypeValue:
+ type: boolean
+
+ IntegerTypeValue:
+ type: integer
+
+ LongTypeValue:
+ type: integer
+ format: int64
+
+ FloatTypeValue:
Review Comment:
I did some experiments, I think the current SingleValueParser implementation
has some problems.
The Jackson writeNumber(float/double) method just writes the string form of
the number by calling
[Float/Double.toString()](https://docs.oracle.com/javase/8/docs/api/java/lang/Double.html#toString-double-)
method internally. The Java doc linked provides an explanation of how the
string conversion is done.
The conversion fundamentally have 2 problems, (1) data that is too big or
too small (outside 10^-3 to 10^7 range) is written in scientific notation, and
the JSON representation will be a string but not number. For example, `10^20`
is written as `"1.0E20"`. (2) the result is lossy, because it is the nearest
approximation to the true value. This is not serializing the float/double to
the exact decimal representation as we discussed above.
For example, there is a very small chance that value `3.0` is sometimes
serialized as `2.99999999999999`, and when deserialized back it is probably
still the 3.0 double value, but sometimes it will be just 2.99999999999999.
This becomes a correctness issue for use cases like row-level filtering, where
user can define a filter against a double like `a < 3` and that can produce
unexpected result. We actually saw this exact issue in the past in
LakeFormation row-level filtering with Athena, so I suggest us be very cautious
here.
In general, I think achieving the true decimal representation will be
actually more spacial and computationally intensive than just storing the
binary representation. We can easily store the binary form of a double by
[Double.doubleToRawLongBits](https://docs.oracle.com/javase/8/docs/api/java/lang/Double.html#doubleToRawLongBits-double-)
to store a long value in the serialized form, and deserialize it back using
the reverse `longBitsToDouble` method. I think we should consider using this
approach.
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