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https://issues.apache.org/jira/browse/CASSANDRA-5563?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sylvain Lebresne resolved CASSANDRA-5563.
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Resolution: Cannot Reproduce
Fix Version/s: (was: 1.2.7)
I'm not able to reproduce this. I've just tested it and binding an empty buffer
to a bind marker that is the argument to token() works fine. And as far as I
can tell, the native protocol has always allowed to bind empty byte buffers so
I'm not sure that has ever be a problem, but if it was, it's fixed now as far
as I can tell.
I'll note that the fact that the token of an empty buffer happens to return the
minimum token is a bit of an implementation detail of our
IPartitioner.getToken() methods. And in particular, with composite partition
key you won't really be able to provide a empty byte buffer for the whole
partition key, so you will have to use more than a single prepared statement to
page in that case.
As for allowing null as argument to token(), I'm not a fan because:
# I don't find {{token(null)}} particularly logical/clean.
# This doesn't really transpose well to composite partition key (for which the
token() method really expect multiple arguments).
# With the native protocol 2.0 supporting a much simpler way to do paging, I
don't see a point in bothering here.
> The CQL3 binary protocol does not allow a user to bind an empty buffer to
> signify the start of the token range
> --------------------------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-5563
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5563
> Project: Cassandra
> Issue Type: Bug
> Components: API
> Affects Versions: 1.2.0
> Reporter: Steven Lowenthal
> Assignee: Sylvain Lebresne
> Priority: Minor
>
> Using CQL2 or CQL3 over thrift, one can issue a query which starts at the
> beginning of the table by binding an empty buffer. The same is true for CQL2
> using calls like get_range_slice. This is not allowed with the binary
> protocol. Here is working sample code for CQL3 over thrift:
> {code}
> CqlPreparedResult stmt =
> _client.prepare_cql3_query(ByteBuffer.wrap("SELECT \" Sequence number\" from
> \"nhanes52simple\" where TOKEN (\" Sequence number\") > TOKEN(?) limit
> 15".getBytes()), Compression.NONE);
> // Bind empty buffer to get query to start at the beginning of
> // the table
> ByteBuffer b = ByteBuffer.wrap(new byte[0]);
> bindVars.add(b);
> int cnt = 0;
> CqlResult result;
> do {
> result = _client.execute_prepared_cql3_query(stmt.itemId, bindVars,
> ConsistencyLevel.ONE);
> // Set up the next chunk, by setting the bind var to the last received
> key
> bindVars.set(0, ByteBuffer.wrap(result.getRows()
> .get(result.getRows().size() -
> 1).getColumns().get(0).getValue()));
> // Count rows
> cnt += result.getRows().size();
> if (cnt > 100)
> Assert.fail("Running past the end of the table: cnt = " + cnt + ",
> size() = " + result.getRows().size());
> } while (result.getRows().size() >= CHUNK_SIZE);
> Assert.assertEquals("Wrong count", 100, cnt);
> }
> {code}
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