Does anybody else use another technique for achieving this idempotency with
counters?
The idempotency problem with counters has to do with what will happen when you
get a timeout. If you reply the write there is a chance of the increment been
applied twice. This is inherent in the current
Each client is writing to a separate keyspace simultaneously. Hence, is there
a lot of switching of keyspaces?
I would think not. If the client app is using one keyspace per connection there
should be no reason for the driver to change keyspaces.
But, I observed that when using a
I am able to fix this error by clearing out the schema_columns system table
on disk. After that, a node can boot successfully.
Does anyone have a clue what's going on here?
Something has come corrupted in the system tables as you say.
A less aggressive way to reset the local schema is to
Calling execute the second time runs the query a second time, and it looks like
the query mutates instance state during the pagination.
What happens if you only call execute() once ?
Cheers
Aaron
-
Aaron Morton
New Zealand
@aaronmorton
Co-Founder Principal Consultant
Apache
Depends on how you have setup the replication.
If you are using SimpleStrategy with RF 1, then there will be a single copy of
each row in the cluster.
If you are using the NetworkTopologyStrategy with RF 1 in each DC then there
will be two copies of each row in the cluster. One in each DC.
I get a lot of TExceptions
What are the exceptions ?
In general counters are slower than writes, but that does not lead them to fail
like that.
Check the logs for errors and/or messages from the GCInspector saying the
garbage collection is going on.
Cheers
A
-
Aaron Morton
In this case I was not thinking about what was happening synchronous to client
request, only that the request was hitting all nodes.
You are right, when reading at LOCAL_ONE the coordinator will only be blocking
for one response (the data response).
Cheers
Aaron
-
Aaron
The limit is just ignored and the entire column family is scanned.
Which limit ?
1. Am I right that there is no way to get some data limited by token range
with ColumnFamilyInputFormat?
From what I understand setting the input range is used when calculating the
splits. The token ranges in
Thankyou for making these issues clear. Currently, in my datamodel, I have
the current second( seconds-from-epoch) as the row key and micro second
with the client number as the column key.
Hence, all the packets received during a particular second
on all the clients are stored in
Thanks Aaron. I've mitigated this by removing the dependency on idempotent
counters. But its good to know the limitations of counters.
Thanks
Jabbar Azam
On 19 May 2014 08:36, Aaron Morton aa...@thelastpickle.com wrote:
Does anybody else use another technique for achieving this idempotency
Hi all, we are using C* 2.0.6 and have set the default_time_to_live parameter
on a number of our LCS column families. I was wondering what would happen if
we were to decrease this value via a table alter. Would subsequent compactions
of data written before that alter honor the new value and
We have a table defined using SizeTieredCompactionStrategy that is used to
store time series data. Over a period of a few days we wrote approximately
200,000 unique time based entries for each of 700 identifiers, i.e. 700 wide
rows with 200,000 entries in each. The table was empty when we started
Sorry I just realized the table name in 2 schema are slightly different,
but still i am not sure why i should not use same index name across
different schema. Below is the instruction to reproduce.
Created 2 keyspace using cassandra-cli
[default@unknown] create keyspace keyspace1 with
thanks - I've fixed it.
Regards,
Maciej
On Mon, May 12, 2014 at 2:50 AM, graham sanderson gra...@vast.com wrote:
Looks cool - giving it a try now (note FYI when building,
TestDataConverter.java line 46 assumes a specific time zone)
On May 11, 2014, at 12:41 AM, Maciej Miklas
Hi *,
I’ve checked DataStax driver code for CQL 3, and it looks like the column
names for particular table are fully loaded into memory, it this true?
Cassandra should support wide rows, meaning tables with millions of
columns. Knowing that, I would expect kind of iterator for column names. Am
I
Maciej,
In CQL3 wide rows are expected to be created using clustering columns. So
while the schema will have a relatively smaller number of named columns, the
effect is a wide row. For example:
CREATE TABLE keyspace.widerow (
row_key text,
wide_row_column text,
data_column text,
You might want to review this blog post on supporting dynamic columns in CQL3,
which points out that “the way to model dynamic cells in CQL is with a compound
primary key.”
See:
http://www.datastax.com/dev/blog/does-cql-support-dynamic-columns-wide-rows
-- Jack Krupansky
From: Maciej Miklas
Hello all,
I am using Cassandra version 2.0.7. I am wondering if collections is
efficient for filtering. We are thinking of using collections to
maintain a list for a customer row but we have to be able to filter on the
collection values.
Select UUID from customer where eligibility_state IN
Collection types cannot be used for filtering (as part of the where
statement).
They cannot be used as a primary key or part of a primary key.
Secondary indexes are not supported as well.
On Mon, May 19, 2014 at 12:50 PM, Raj Janakarajan
r...@zephyrhealthinc.comwrote:
Hello all,
I am using
Raj,
Secondary indexes across CQL3 collections were introduced into 2.1 beta1,
so will be available in future versions. See
https://issues.apache.org/jira/browse/CASSANDRA-4511
If your main concern is performance then you should find another way to
model the data: each collection is read
Thank you Patricia. This is helpful.
Raj
On Mon, May 19, 2014 at 10:54 AM, Patricia Gorla patri...@thelastpickle.com
wrote:
Raj,
Secondary indexes across CQL3 collections were introduced into 2.1 beta1,
so will be available in future versions. See
Thanks Eric for the information. It looks like it will be supported in
future versions.
Raj
On Mon, May 19, 2014 at 10:03 AM, Eric Plowe eric.pl...@gmail.com wrote:
Collection types cannot be used for filtering (as part of the where
statement).
They cannot be used as a primary key or part
Has anyone experienced network i/o issues with ec2? We are seeing a lot of
these in our logs:
HintedHandOffManager.java (line 477) Timed out replaying hints to
/10.0.x.xxx; aborting (15 delivered)
and these...
Cannot handshake version with /10.0.x.xxx
and these...
java.io.IOException: Cannot
I think there are several issues in your schema and queries.
First, the schema can't efficiently return the single newest post for every
author. It can efficiently return the newest N posts for a particular
author.
On Fri, May 16, 2014 at 11:53 PM, 後藤 泰陽 matope@gmail.com wrote:
But I
For XFS, using noatime and nodirtime isn't really useful either.
http://xfs.org/index.php/XFS_FAQ#Q:_Is_using_noatime_or.2Fand_nodiratime_at_mount_time_giving_any_performance_benefits_in_xfs_.28or_not_using_them_performance_decrease.29.3F
On Sat, May 17, 2014 at 7:52 AM, James Campbell
On Mon, May 19, 2014 at 6:39 AM, mahesh rajamani
rajamani.mah...@gmail.comwrote:
Sorry I just realized the table name in 2 schema are slightly different,
but still i am not sure why i should not use same index name across
different schema. Below is the instruction to reproduce.
Created 2
Ah, that is interesting, Patricia. Since they can be a secondary index,
it's not too far off for them being able to be a primary key, no?
On Mon, May 19, 2014 at 1:54 PM, Patricia Gorla
patri...@thelastpickle.comwrote:
Raj,
Secondary indexes across CQL3 collections were introduced into 2.1
I'm not sure about that — allowing collections as a primary key would be a
much different implementation than setting up a secondary index.
The primary key in CQL3 is actually the partition key which determines
which token the row is assigned, so you would still need to have one
partition key.
It's a good idea to increase phi_convict_threshold to at least 12 on EC2.
Using placement groups and single-tenant systems will certainly help.
Another optimization would be dedicating an Enhanced Network Interface (
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-eni.html)
specifically
Hallo Jack,
You have given a perfect example for wide row. Each reading from sensor
creates new column within a row. It was also possible with Hector/CLI to have
millions of columns within a single row. According to this page
http://wiki.apache.org/cassandra/CassandraLimitations single row
Hi James,
Clustering is based on rows. I think that you meant not clustering columns, but
compound columns. Still all columns belong to single table and are stored
within single folder on one computer. And it looks to me (but I’am not sure)
that CQL 3 driver loads all column names into memory
We did something similar with a split cloud/physical hardware deployment.
There was a weird requirement that app authentication data (fortunately in
it's own keyspace already) could not live on the cloud (shrug).
This ended up being a simple configuration change in the schema just like
your
Hi Aaron,
I've seen the code which you describe (working with splits and intersections)
but that range is derived from keys and work only for ordered partitioners (in
1.2.15).
I've already got one confirmation that in C* version I use (1.2.15) setting
limits with setInputRange(startToken,
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