Just FYI, you may want to do put the return value of cell.buffer() in a
variable instead of calling it twice, because there's no guarantee that
you will get the same (cached) ByteBuffer object on the second call.
Also, you may want to do a rewind() first, just in case...
On 28/01/2022 09:22, Neophytos Demetriou wrote:
I've solved the issue with the following for the time being:
byte[] arr =new byte[cell.buffer().remaining()]; cell.buffer().get(arr);
I shouldn't have been calling array() in the first place it seems.
- Neophytos
On Fri, Jan 28, 2022 at 2:06 AM Neophytos Demetriou
<neophy...@gmail.com> wrote:
Hi, thanks for the prompt reply.
I've tried this. Here's what I'm writing:
bytes: 3 capacity: 3 limit: 3 offset: 0
Here's what I'm reading:
cell buffer size: 1048576 capacity: 1048576 limit: 212 arrayOffset: 0
It still does not seem right. I would have expected Cassandra to
allocate a buffer the size of the text field. Unless I'm missing
something, org.apache.cassandra.db.marshal.AbstractType#read
already does this. It calls
org.apache.cassandra.utils.ByteBufferUtil#read that allocates a
byte array the size of the given length. I'm still checking but it
could be that the readUnsignedVInt call in AbstractType#read reads
the wrong thing under the given circumstances (very likely an
issue on my end). I would welcome any ideas on how to debug this.
- Neophytos
On Thu, Jan 27, 2022 at 5:43 PM Bowen Song <bo...@bso.ng> wrote:
I'm not a Java developer, but based on my best knowledge,
ByteBuffer.array() method returns the whole byte array, not
just the part of the byte array that's meaningful (i.e. has
ever been written to). You may want to check the difference
between the bb.capacity() and bb.limit(), and also check the
bb.arrayOffset() because the first element is not always at
beginning of the byte array.
On 27/01/2022 22:11, Neophytos Demetriou wrote:
Hi,
I'm new to the list but not new to Cassandra. I'm writing an
app on top of C* and I have come across an issue (huge cell
buffer size after applying a mutation) that I haven't been
able to resolve yet. I would appreciate any suggestions/help
to resolve this. Here are the details:
1. I have a column family defined as follows:
TableMetadata.Builder metadata =
TableMetadata
.builder(KEYSPACE1, CF_STANDARD1)
.addPartitionKeyColumn("key", Int32Type.instance)
.addRegularColumn(
"a", MapType.getInstance(AsciiType.instance,
SetType.getInstance(UTF8Type.instance,false),false))
.addRegularColumn("b", UTF8Type.instance);
2. And here's a test that I wrote and works on cassandra-4.0
branch:
Row.Builder builder = BTreeRow.unsortedBuilder(); builder.newRow(Clustering.EMPTY);
ColumnMetadata def =metadata.getColumn(new ColumnIdentifier("b", true)); Cell<?> cell =
BufferCell.live(def, System.currentTimeMillis(), UTF8Type.instance.decompose("/b1"));
builder.addCell(cell); PartitionUpdate update = PartitionUpdate.singleRowUpdate(metadata, dk,
builder.build()); new Mutation(update).apply(); Row row = Util.getOnlyRow(Util.cmd(cfs,
dk).withLimit(1).build()); assertEquals(3, row.getCell(def).buffer().array().length);
3. However, in my app when I do the getOnlyRow after applying
the mutation the string value of b is 3 but the
buffer().array().length is 1048576.
4. Restarting the app (which starts the cassandra daemon),
fixes the issue i.e. getOnlyRow returns the correct buffer size.
5. I'm importing cassandra-all 4.0.1 and the app uses jdk-11.
If you need further info, please do not hesitate to ask.
- Neophytos
PS. I'm experimenting with C* internals for the first time so
it's very likely I'm doing something wrong.
