On 12/24/2016 08:55 AM, Misa wrote:
I'm using a different scheme (might be suboptimal in your case).
I store object version id in object attributes. Every update increases
version number. So the update first reads object version from rados
and then creates transaction like this
```python
wop = ctx.write_op_create()
wop.assert_exists()
wop.cmpxattr('version', rados.CmpXattrOp.eq, current_version)
wop.setxattr('version', new_version)
wop.write_full(data)
```
If it fails because of the condition, I just retry. Creating new
object is similar
```
wop = ctx.write_op_create()
wop.create(True)
wop.setxattr('version', version)
wop.write_full(data)
```
That looks like the kind of thing I want to do.
A question: The write_op_create() starts transaction, and the
write_full() closes it? And you get a Python exception if there is a
problem?
Cool.
Examples are so helpful.
Thanks,
-kb
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