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https://issues.apache.org/jira/browse/CASSANDRA-20425?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17933958#comment-17933958
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Ruslan Fomkin commented on CASSANDRA-20425:
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The solution is discussed in
https://issues.apache.org/jira/browse/CASSANDRA-20389 to lift the limit and
update the documentation. As you correctly noticed there are already tables
with longer names than 48 chars, since nothing was preventing.
> Table name length validation accidentally lost since Cassandra 4
> ----------------------------------------------------------------
>
> Key: CASSANDRA-20425
> URL: https://issues.apache.org/jira/browse/CASSANDRA-20425
> Project: Apache Cassandra
> Issue Type: Bug
> Reporter: Nadav Har'El
> Priority: Normal
>
> Cassandra's documentation
> [https://cassandra.apache.org/doc/stable/cassandra/cql/ddl.html] claims that:
> _Both keyspace and table name ... are limited in size to 48 characters (that
> limit exists mostly to avoid filenames (which may include the keyspace and
> table name) to go over the limits of certain file systems)._
> I checked, and although this limitation was true in Cassandra 3, it is no
> longer enforced since Cassandra 4.
> It seems this change was not intentional, and happened eight years ago in
> commit [this
> commit|https://github.com/apache/cassandra/commit/af3fe39dcabd9ef77a00309ce6741268423206df].
> Before this commit, we had
> {{public static boolean isNameValid(String name) {}}
> return name != null && !name.isEmpty() && name.length() <=
> SchemaConstants.NAME_LENGTH && PATTERN_WORD_CHARS.matcher(name).matches();
> }
> After it, this definition was dropped, IndexMetadata.isNameValid() is used,
> and this one never had a name length check.
> We can see that this dropping of the limit check was unintentional in several
> ways. First, the documentation still mentions this no-longer-existing
> limitation. Second, the code still has SchemaConstants.NAME_LENGTH existing
> and set to 48, but no longer used. Or rather- it is used - but only in error
> messages, which no longer match what is actually being tested!
> I think Cassandra should either return this name length limit that was
> accidentally dropped 8 years ago, or we could decide officially that this
> name length limit is lifted - and drop it from the documentation and also all
> mentions of NAME_LENGTH in error messages (and remove this constant entirely).
> But before deciding what to do, I want to make another point. The
> documentation rightly explained the original raison d'etre for this
> 48-character limitation: "that limit exists mostly to avoid filenames to go
> over the limits of certain file systems". This reason is still relevant. I
> checked what happens when on a standard Linux filesystem I try to create a
> table name with a 300-character name. On Cassandra 4, the behavior was
> reasonable - I got a bizarre error, but afterwards the database was still
> functional. On Cassandra 5, the result was a disaster - Cassandra hang on
> some strange loop of IO errors and never recovered. So if the decision is to
> allow longer-than-48-chars table names, as were allowed in the last 8 years,
> we should consider whether we should have a higher limit instead, or perhaps
> try to catch the error of filenames too long for this filesystem and fail
> more gracefully.
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