It’s my understanding that the way Cassandra replicates data across nodes is
NOT sharding. Can someone provide a better explanation or correct my
understanding?
B.
Thanks Andi. The reason I was asking is that even though my nodes have been
100% available and no write has been rejected, when running an incremental
repair, the logs still indicate that some ranges are out of sync (which
then results in large amounts of compaction), how can this be possible?
I
Hi,
right, QUORUM means that data is written to all replicas but the coordinator
waits for QUORUM responses before returning back to client. If a replica is out
of sync due to network or internal issue than consistency is ensured through:
- HintedHandoff (Automatically
On Mon, Jan 19, 2015 at 2:29 AM, Kevin Burton bur...@spinn3r.com wrote:
So ConsistencyLevel.ONE and if not exists are essentially mutually
incompatible and shouldn’t the driver throw an exception if the user
requests this configuration?
The subtlety is that this consistency level (CL.ONE in
Hi,
Does Cassandra fetches complete partition if I include Cluster key in
where clause.
Or What is the difference in:
1. Select * from column_family where partition_key = 'somekey' limit 1;
2. Select * from column_family where partition_key = 'somekey' and
clustering_key = 'some_clustring_key';
Partitioning is similar to sharding.
Mohammed
From: Adaryl Bob Wakefield, MBA [mailto:adaryl.wakefi...@hotmail.com]
Sent: Monday, January 19, 2015 8:28 PM
To: user@cassandra.apache.org
Subject: sharding vs what cassandra does
It’s my understanding that the way Cassandra replicates data across
Sharding is a type of database partitioning. The sweet spot of cassandra is
to supporting fast random reads. This is achieved by grouping data based on
a partition key and replicate to different nodes. The querying should be in
such a way to look up data of one partition at a time.
Grouping data
Hi,
If we think it the perspective of column family (table), its rows are split
into different nodes(Sharding) based on ring concept in Cassandra.
But the core unit of data storage (rows) id not spit across nodes, only copy is
maintained in different rows. All column associated to a single
Hi,
When writing to Cassandra using CL = Quorum (or anything less than ALL), is
it correct to say that Cassandra tries to write to all the replica, but
only waits for Quorum?
If so, what can cause some replica to become out of sync when they're all
online?
Thanks
Flavien
Thanks Roland. Good to know, I will try that. Do you know the JIRA ticket
number of that bug?
Thanks,
Flavien
On 19 January 2015 at 06:15, Roland Etzenhammer r.etzenham...@t-online.de
wrote:
Hi Flavien,
I hit some problem with minor compations recently (just some days ago) -
but with many
Since our workload is spread globally, we spread our nodes across AWS
regions as well: 2 nodes per zone, 6 nodes per region (datacenter) (RF 3),
12 nodes total (except during upgrade migrations). We autodeploy into VPCs.
If a region goes bad we can route all traffic to another and bring up a
e.g.
CREATE TABLE usertable_cache (
user_id uuid,
dept_id uuid,
location_id text,
locationmap_id uuid,
PRIMARY KEY ((user_id, dept_id), location_id)
) WITH
bloom_filter_fp_chance=0.01 AND
caching='{keys:ALL, rows_per_partition:1000}' AND
comment='' AND
My question is specifically for row cache? As in cassandra 2.1.2 when I
populate a Column Family with 1000 rows for a partition and
rows_per_partition setting is 1000 for the Column Family then for first and
last row, it says cache miss.. if I mention specific row key in query? If I
increase
Ah.. six replicas. At least its super inexpensive that way (sarcasm!)
Well it's up to you to decide what your data locality and fault tolerance
requirements are.
If you want to run two DC's, costs are going to increase since each DC has
a full set of replicas within itself. But you get the
Hi,
we have had an issue with one of our nodes today:
1. Due to a wrong setup the starting node failed to properly bootstrap.
It was shown as UN in the cluster however did not contain any data and
we shut it down to fix our configuration issue.
2. We figured we need to remove the node from
Hello,
My feeling is you got the hole CAS operations concept wrong. CAS operations
a.k.a lightweight transactions are not meant to used everywhere, only in
specific parts of your application where serialisable consistency is
necessary. For any other case there is a variety of consistency levels
It depends on your version of Cassandra. I would suggest starting with
this, which describes the differences between 2.0 and 2.1
http://www.datastax.com/dev/blog/row-caching-in-cassandra-2-1
In particular:
In previous releases, this cache has required storing the entire
partition in memory,
I've seen removenode hang indefinitely also (per CASSANDRA-6542).
Generally speaking, if a node is in good health and you want to take it out
of the cluster for whatever reason (including the one you mentioned),
nodetool decommission is a better choice. Removenode is for when a node is
18 matches
Mail list logo
