Thanks Josh and Keith.
This is exactly what I am looking. I have set some value for row through
conditional mutation if that exists I am updating the entries of a row.
So I think in that case conditional mutational will work. It will not be
interrupted by other threads.
Thanks
Shweta
On Monday 02 November 2015 09:30 PM, Keith Turner wrote:
On Fri, Oct 30, 2015 at 7:36 AM, shweta.agrawal
<[email protected] <mailto:[email protected]>> wrote:
Hi,
Is transaction type facility available in Accumulo?
I have read about transaction in accumulo which says " Accumulo
guarantees these ACID properties for a single mutation (a set of
changes for a single row) but does not provide support for atomic
updates across multiple rows"
In my case:
If one thread is updating the fields of a document then this
document should be locked so that other thread cannot modify that
document.
I am trying to achieve this by a query through conditional
mutation. I am checking whether the particular entry exist or not
then updating. But the problem is I am doing this through 150
threads. If one thread finds and updating particular entry then
other thread should not get it.
So is this the case in conditional write?
This could be done with a conditional write and a sequence number
column per row.
Could do something like the following
* Read row using isolated scanner or whole row iterator.
* Assume row has a column like sync:seq.
* Make changes to row in client.
* Write conditional mutation with condition that sync:seq is what
was read earlier. Also increment the sequence number
With this pattern only one client can succesfully read-modify-write a
row concurrently. In the case where the column synch:seq does not
exist, the conditional mutation should assert it does not exist and
set it to an initial value.
Is this what you are looking for? Or are you trying to do something else?
We are achieving same thing through mongoDB by find and modify
feature.
If one thread get particular document to update from conditional
write then other thread should get that particular document.
Please provide your inputs
Thanks
Shweta
