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https://issues.apache.org/jira/browse/CASSANDRA-20723?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17985161#comment-17985161
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Nadav Har'El commented on CASSANDRA-20723:
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Strangely, I checked experimentally that only the parsing of the the
**exponent** is broken when parsing CQL "decimal" literals. The precision is
not broken: If I use the literal
3.14159265358979323846264338327950288419716939937510 with 50 significant
digits, on all versions of Cassandra (3, 4, 5) it is correctly parsed and
stored, and **not** converted into a double which would have caused precision
loss. So only the exponent is incorrectly limited in Cassandra 4 and 5, to 309.
Strange.
> decimal literal parsed as as a double, with misleading error message
> --------------------------------------------------------------------
>
> Key: CASSANDRA-20723
> URL: https://issues.apache.org/jira/browse/CASSANDRA-20723
> Project: Apache Cassandra
> Issue Type: Bug
> Reporter: Nadav Har'El
> Priority: Normal
>
> According to the Cassandra documentation, the CQL "decimal" type is based on
> Java's BigDecimal type. The documentation of that type explains that the
> so-called "scale" of this number (fractional digits minus exponent) can be
> very large, and in particular, for example, the number "1e2147483647" (the
> exponent is 2^31-1) should be a valid decimal.
> However, experimentally if I create a table with a "decimal" clustering key
> and try to insert any exponent 309 or higher, I get an error:
> {{CREATE TABLE tbl (p int, c decimal, PRIMARY KEY (p, c))}}
> {{INSERT INTO tbl (p, c) VALUES (1, 1e309)}}
> The error I get is:
> {{cassandra.protocol.SyntaxException: <Error from server: code=2000 [Syntax
> error in CQL query] message="Failed parsing statement: [INSERT INTO tbl (p,
> c) VALUES (1, 1e309)] reason: NumberFormatException Character I is neither a
> decimal digit number, decimal point, nor "e" notation exponential mark.">}}
> This error message is silly and misleading - which "Character I" does it
> refer to? But beyond the wrong error message, it is also wrong to be an error
> at all, because as I explained above 1e309 should have been a valid decimal
> value - even 1e2147483647 is.
> Since 1e308 is accepted but 1e309 is not, I suspect the bug is that the
> decimal literal is parsed as a double-precision number and then assigned into
> a decimal. But this is wrong - it means that with inline literals (without
> prepared statements) we cannot actually use the full range of the decimal
> type: We cannot use the full range of the exponent, and probably also can't
> use arbitrary precision (but I didn't test this).
> Is there a different way to specify a decimal literal? The documentation
> doesn't seem to say anything about this question. I tried maybe a string like
> "1e309" might work to initialize a decimal, but no - it doesn't seem to work.
> This seems to be a *regression in Cassandra 4 and 5:* I tested Cassandra
> 3.11.17, and it doesn't have this bug: It is able able to parse 1e309 and
> even 1e2147483647 just fine and assign them into the decimal clustering-key
> in my test. But the bug does exist on Cassandra 4.1.6 and 5.0.0 which I
> tested.
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