Re: why dose it still have to seach in SSTable when getting data in memtable in the read flow？

@Bhuvan Rawal @Jasonstack Thanks a lot, it's very helpful! -- 赵豫峰 环信即时通讯云/研发 -- Original -- From: "Bhuvan Rawal"; Date: Mon, Mar 27, 2017 08:42 PM To: "user"; Subject: Re: why

Re: Effective partition key for time series data, which allows range queries?

Have you looked at KairosDB schema ? https://kairosdb.github.io/ Regards, Noorul On Tue, Mar 28, 2017 at 6:17 AM, Ali Akhtar wrote: > I have a use case where the data for individual users is being tracked, and > every 15 minutes or so, the data for the past 15 minutes is

Effective partition key for time series data, which allows range queries?

I have a use case where the data for individual users is being tracked, and every 15 minutes or so, the data for the past 15 minutes is inserted into the table. The table schema looks like: user id, timestamp, foo, bar, etc. Where foo, bar, etc are the items being tracked, and their values over

Issues while using TWCS compaction and Bulkloader

Hi, We have a Cassandra 3.0.8 cluster, and we use the Bulkloader to upload time series data nightly. The data has a 3day TTL, and the compaction window unit is 1h. Generally the data fits into memory, all reads are served

When is anti-entropy repair required?

Hi, Trying to get some clarifications on this post: https://docs.datastax. com/en/cassandra/3.0/cassandra/operations/opsRepairNodesWhen.html As far as I understand it, repairs to account for the fact that nodes could go down (for short of long period of time) The 2 main reasons for repairing

Re: Weird error: InvalidQueryException: unconfigured table table2

Just wish that an error like: "Table x not found in keyspace y" You are welcome to open JIRA with type Improvement. Best regards, Vladimir Yudovin, Winguzone - Cloud Cassandra Hosting On Sun, 26 Mar 2017 13:31:33 -0400 S G sg.online.em...@gmail.com wrote Thanks, got

Re: Help with data modelling (from MySQL to Cassandra)

Great suggestion! Thanks Avi! On Mon, Mar 27, 2017 at 3:47 PM, Avi Kivity wrote: > You can use static columns to and just one table: > > > CREATE TABLE documents ( > > doc_id uuid, > > element_id uuid, > > description text static, > > doc_title text static, >

Understanding DynamicSnitch Scores.

Hi, I am seeing the DynamicSnitch scores on my node one with 3.44775023338358 and other with 0.884715810185486 so my current node will send full request to node with Value 3.44 and digest request to node with value 0.88 So the higher the value >1 means the node responding the fastest ?? node

Pagination and timeouts

I have a table with some 1M rows, and I would like to get the partition key of each row. Using the java driver (2.1.9), I'm executing the query select distinct key from table; The result set is paginated automatically. My C* cluster has two datacenters, and when I run this query using

Re: How can I scale my read rate?

By default the TokenAwarePolicy does shuffle replicas, and it can be disabled if you want to only hit the primary replica for the token range you're querying : http://docs.datastax.com/en/drivers/java/3.0/com/datastax/driver/core/policies/TokenAwarePolicy.html On Mon, Mar 27, 2017 at 9:41 AM Avi

Re: Help with data modelling (from MySQL to Cassandra)

You can use static columns to and just one table: CREATE TABLE documents ( doc_id uuid, element_id uuid, description text static, doc_title text static, element_title text, PRIMARY KEY (doc_id, element_id) ); The static columns are present once per unique

Re: why dose it still have to seach in SSTable when getting data in memtable in the read flow？

Also Cassandra working unit is Cells so in a partition there may be possibility of some cells in a row being present in memtable and others may be located in memtable therefore the need of reconciling partition data. @Jason's point is valid too - User defined timestamp may put sstable cells

Re: why dose it still have to seach in SSTable when getting data in memtable in the read flow？

Hi, Cassandra uses last-writetime-win strategy. In memory data doesn't mean it is the latest data due to custom write time, if data is also in Sstable, Cassandra has to read it and reconcile. Jasonstack On Mon, 27 Mar 2017 at 7:53 PM, 赵豫峰 wrote: > hello, I get the message

why dose it still have to seach in SSTable when getting data in memtable in the read flow？

hello, I get the message that "If the memtable has the desired partition data, then the data is read and then merged with the data from the SSTables. The SSTable data is accessed as shown in the following steps." in "how is data read?" chapter in

Re: Help with data modelling (from MySQL to Cassandra)

Thank you Matija, because i am newbie, it was not clear for me that i am able to query by the partition key (not providing the clustering key), sorry about that! Zoltan. On Mon, Mar 27, 2017 at 1:54 PM, Matija Gobec wrote: > Thats exactly what I described. IN queries can

Re: Help with data modelling (from MySQL to Cassandra)

Thats exactly what I described. IN queries can be used sometimes but I usually run parallel async as Alexander explained. On Mon, Mar 27, 2017 at 12:08 PM, Zoltan Lorincz wrote: > Hi Alexander, > > thank you for your help! I think we found the answer: > > CREATE TABLE

Re: Help with data modelling (from MySQL to Cassandra)

Hi Alexander, thank you for your help! I think we found the answer: CREATE TABLE documents ( doc_id uuid, description text, title text, PRIMARY KEY (doc_id) ); CREATE TABLE nodes ( doc_id uuid, element_id uuid, title text, PRIMARY KEY (doc_id, element_id) ); We

Re: How can I scale my read rate?

Is the driver doing the right thing by directing all reads for a given token to the same node? If that node fails, then all of those reads will be directed at other nodes, all oh whom will be cache-cold for the the failed node's primary token range. Seems like the driver should distribute

Re: Help with data modelling (from MySQL to Cassandra)

Hi Zoltan, you must try to avoid multi partition queries as much as possible. Instead, use asynchronous queries to grab several partitions concurrently. Try to send no more than ~100 queries at the same time to avoid DDOS-ing your cluster. This would leave you roughly with 1000+ async queries