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CASSANDRA QUESTIONS

Cassandra Replication Factor
Cassandra Replication Factor
I wish did fix the issue. If you exclude DC1 - it won't get data written for that keyspace, nor data will be read from the DC1. Before switching off DC1, make sure that you perform nodetool repair on the serves in DC2, to make sure that you have all
TAG : cassandra
Date : November 18 2020, 07:00 PM , By : C.Chen
How many seed nodes need for apache cassandra cluster(3.11.4) cluster with 10 nodes
How many seed nodes need for apache cassandra cluster(3.11.4) cluster with 10 nodes
wish help you to fix your issue You have to understand that seed nodes are nothing special except for you to expect one of them to always be reachable when a nodes comes up after being added to the cluster so they can propagate the cluster topology t
TAG : cassandra
Date : October 21 2020, 06:10 AM , By : RandySavage
Scylla, datastax-java-driver integration problem
Scylla, datastax-java-driver integration problem
Any of those help What happened here is that Scylla chose to do probabilistic read repair and detected mismatch before CL was reached. At this point it started to do repair between all three replicas and failed to read from all of them (either due to
TAG : cassandra
Date : October 20 2020, 06:10 PM , By : TechnoChimp
Inet address 127.0.0.1:9042 is not available when use ccm start
Inet address 127.0.0.1:9042 is not available when use ccm start
This might help you There could be several reasons: You have Cassandra process that is already running - check, with ps -aux|grep -i cassandra that you don't have other Cassandra processes running already on localhost You haven't created additional i
TAG : cassandra
Date : October 15 2020, 06:10 AM , By : Jonathan Dixson
Should I set foreign keys in Cassandra tables?
Should I set foreign keys in Cassandra tables?
seems to work fine The main Cassandra concept is that you design tables based off of your queries (as writes to the table have no restrictions). The design is based off of the query filters. An application that queries a table by some ID is somewhat
TAG : cassandra
Date : October 14 2020, 02:00 AM , By : dhulfiqar
Why I can't create a UDT with name profiles?
Why I can't create a UDT with name profiles?
should help you out Update: it looks like a bug. I suggest to use word profile instead...Original answer:
TAG : cassandra
Date : October 13 2020, 03:00 PM , By : hetavi kadam
Cassandra unable to query sum of rows from a table
Cassandra unable to query sum of rows from a table
Does that help This kind of queries won't work with Cassandra when you have relatively big data in it - such kind of queries requires the scanning of the whole database, and reading all data in it. Cassandra is great when you know the partition that
TAG : cassandra
Date : October 13 2020, 01:00 AM , By : Bryan Sullivan
If I give row_cache_size_in_mb =5Gb in cassandra.yaml file, does cassandra reserves 5GB from Heap Memory?
If I give row_cache_size_in_mb =5Gb in cassandra.yaml file, does cassandra reserves 5GB from Heap Memory?
I think the issue was by ths following , It will let it grow to that size over time. Can use nodetool info to see the current size and limit and nodetool setcachecapacity to change it at runtime. Note that its kinda an estimate though and heap can gr
TAG : cassandra
Date : October 12 2020, 11:00 PM , By : Ryan McReady
What does Cassandra return to client on dropped mutations?
What does Cassandra return to client on dropped mutations?
it should still fix some issue On writes, if enough replicas respond within write_request_timeout_in_ms (2 seconds by default) you will see successful responses at the client.So consider that case where you are writing with consistency QUORUM with a
TAG : cassandra
Date : October 12 2020, 03:00 PM , By : Mihir Patel
How JanusGraph gremlin knows that it should use Cassandra and not Hadoop?
How JanusGraph gremlin knows that it should use Cassandra and not Hadoop?
Hope this helps Maybe I should fake the gremlin and set HADOOP_HOME to Cassandra installation?
TAG : cassandra
Date : October 12 2020, 01:00 PM , By : Zjfsfanhqz Calabrbz
Recommended number of partitions in Cassandra
Recommended number of partitions in Cassandra
around this issue After about 1 billion partitions per node full repairs (non incremental) begin to have pretty serious issues with over streaming. Particularly with smaller partitions as the validation compactions run slower.Ideally i would recommen
TAG : cassandra
Date : October 12 2020, 03:00 AM , By : David
Why does Cassandra major compaction fail to clear expired tombstones?
Why does Cassandra major compaction fail to clear expired tombstones?
Hope this helps The tombstone markers generated during your major compaction are just that, markers. The data has been removed but a delete marker is left in place so that the other replicas can have gc_grace_seconds to process them too. The tombston
TAG : cassandra
Date : October 11 2020, 02:00 PM , By : Yoander Iñiguez Berm
Janusgraph delete vertex and commit completes but next operation still sees the vertex
Janusgraph delete vertex and commit completes but next operation still sees the vertex
like below fixes the issue Mutations to Cassandra do not show up instantlyCassandra is what's known as an eventually-consistent database, this means that changes that are written to it are not guaranteed to be immediately visible to all consumers. It
TAG : cassandra
Date : October 11 2020, 12:00 AM , By : Jeroen Eelants
Cassandra Error : expected 8 or 0 byte long for date
Cassandra Error : expected 8 or 0 byte long for date
Hope that helps the mintimeuuid function expects timestamp as parameter, but you pass a string. You need to pass variable with java.util.Date type instead. See the documentation for mapping between Java type and CQL types.
TAG : cassandra
Date : October 10 2020, 10:00 PM , By : Piotr Grabowski
When does driver datastax driver paging yields fewer pages than requested?
When does driver datastax driver paging yields fewer pages than requested?
this one helps. Note that setting a fetch size doesn’t mean that Cassandra will always return the exact number of rows, it is possible that it returns slightly more or less results
TAG : cassandra
Date : October 10 2020, 04:00 PM , By : ypk
Does updating a row in a Cassandra table also change the write time?
Does updating a row in a Cassandra table also change the write time?
it fixes the issue Here is an example showing that the timestamp changes only on the column updated:
TAG : cassandra
Date : October 10 2020, 07:00 AM , By : Steve
How to search record using ORDER_BY without the partition keys
How to search record using ORDER_BY without the partition keys
Any of those help First, ORDER BY is really quite superfluous in Cassandra. It can only operate on your clustering columns within a partition, and then only on the exact order of the clustering columns. The reason for this, is that Cassandra reads se
TAG : cassandra
Date : October 10 2020, 05:00 AM , By : os3lyejiwtkvzp9m
Exporting a Cassandra Keyspace with Data to a file
Exporting a Cassandra Keyspace with Data to a file
I hope this helps you . Looking at the DataStax documentation, you should be able to do that using the COPY command as follows (for a single table):
TAG : cassandra
Date : October 09 2020, 12:00 PM , By : John
Increase request timeout for CQL from NiFi
Increase request timeout for CQL from NiFi
seems to work fine Most probably you're getting an exception because you're performing query on non-partition key - in this case, the query is distributed to the all nodes, and requires to go through all available data, and this is very slow if you h
TAG : cassandra
Date : October 07 2020, 11:00 PM , By : venkat p
Is there any config that can be enabled to set a precision for Double value in cassandra datastax java driver?
Is there any config that can be enabled to set a precision for Double value in cassandra datastax java driver?
help you fix your problem The options provided by cqlsh are only used for displaying the data - internally all data are handled as normal doubles.The same is for DataStax Java driver - it just returns the double, and it's responsibility of developer
TAG : cassandra
Date : October 07 2020, 04:00 PM , By : Praveen Yadav
How is Cassandra not consistent but HBase is?
How is Cassandra not consistent but HBase is?
seems to work fine Cassandra is consistent, eventually. Based in Brewer's theorem (also known as CAP theorem), distributed data systems can only guarantee to achieve 2 of the following 3 characteristics: Consistency. Availability. Partition tolerance
TAG : cassandra
Date : October 07 2020, 03:00 PM , By : Iniesta
IP v6 address socket creation fails with “Unable to create SSL socket” error
IP v6 address socket creation fails with “Unable to create SSL socket” error
should help you out You need to comment out the following line in the file /etc/cassandra/jvm.options
TAG : cassandra
Date : October 07 2020, 03:00 PM , By : Domino
Should I create a new column for a field I need to read often? Cassandra
Should I create a new column for a field I need to read often? Cassandra
I wish this helpful for you I have a cassandra database with id and jsonData fields.I am often fetching the value of this particular field in the jsonData. , Assuming your structure is
TAG : cassandra
Date : October 07 2020, 07:00 AM , By : Dean_Layton
Restart instance cassandra - commitlog, saved cache warnings?
Restart instance cassandra - commitlog, saved cache warnings?
Any of those help Sometimes you'll see messages like these in your system.log on startup. By reading these messages, it appears (to me) that you've cleared the node's data, but didn't also wipe the commitlog and saved_caches directories. At any rate,
TAG : cassandra
Date : October 06 2020, 02:00 PM , By : walkinator
WHICH is BETTER > Triggers or TTL
WHICH is BETTER > Triggers or TTL
I think the issue was by ths following , So while "better" is definitely subjective, what I'll do here is talk about what you need to do to enable both a TTL and a trigger in Cassandra. Then you can decide for yourself.To implement a TTL, you need to
TAG : cassandra
Date : October 06 2020, 03:00 AM , By : James McGregor-Coope
How to have similar cassandra.yaml across cluster?
How to have similar cassandra.yaml across cluster?
it helps some times It's not possible to have includes in yaml file directly, but nothing prevents you from using Ansible/Puppet/Chef, or any other framework to process template of cassandra.yaml file, and substitute variables to generate real cassan
TAG : cassandra
Date : October 05 2020, 06:00 PM , By : josh coyle
Cassandra metric TotalDiskSpaceUsed: does it include replication factor?
Cassandra metric TotalDiskSpaceUsed: does it include replication factor?
will help you That should include the RF data - whatever is stored in the sstables, which includes replicated data.
TAG : cassandra
Date : October 05 2020, 01:00 AM , By : Vijay
Why does cassandra count query using "allow filtering" when being executed without mentioning it in my code?
Why does cassandra count query using "allow filtering" when being executed without mentioning it in my code?
this one helps. ALLOW FILTERING is implicitly added to the generated CQL query by Spark-Cassandra connector.
TAG : cassandra
Date : October 04 2020, 04:00 AM , By : Houda Jamal
Retrieve rows from last 24 hours
Retrieve rows from last 24 hours
To fix this issue Cassandra has a very limited date operation support. What you need is a custom function to do date math calculation.Inspired from here. How to get Last 6 Month data comparing with timestamp column using cassandra query?
TAG : cassandra
Date : October 03 2020, 09:00 AM , By : Nayaz
JanusGraph .graphml file schema issue while creating in Cassandra
JanusGraph .graphml file schema issue while creating in Cassandra
To fix this issue I'm not sure if this is the problem but that GraphML does not include the expected edge and vertex labels that the TinkerPop GraphMLReader expects (i.e. labelE and labelV respectively). You can either adjust your data or configure t
TAG : cassandra
Date : October 02 2020, 11:00 PM , By : Jayesh
ScyllaDB - [Invalid query] message="marshaling error: Milliseconds length exceeds expected (6)"
ScyllaDB - [Invalid query] message="marshaling error: Milliseconds length exceeds expected (6)"
I hope this helps you . You have hr:min:sec.millisec -> Millisec can be up to 999/1000 so essentially that's what the error is saying.The 3 INSERT statement you did are correct in terms of syntax.
TAG : cassandra
Date : October 02 2020, 10:00 PM , By : SteveyB
Bootstrapping cassandra with different version and OS
Bootstrapping cassandra with different version and OS
will be helpful for those in need You can run Cassandra on different Linux versions, but it's recommended to use the same version of Cassandra itself - 3.0 3.11 are different series, and use of them together in the same cluster is recommended only d
TAG : cassandra
Date : October 02 2020, 06:00 PM , By : Pankaj
Cassandra returns Unordered result set for numeric values
Cassandra returns Unordered result set for numeric values
hop of those help? I ran your exact statements and produced the same result. But I also adjusted your query to run the token function, and this is what it produced:
TAG : cassandra
Date : October 02 2020, 04:00 PM , By : Joan
Cassandra Best Practice for Deleting Large Amounts of Rows
Cassandra Best Practice for Deleting Large Amounts of Rows
I wish this help you You need to delete different ways, depending on you schema (in priority order, from best to worse): truncate table delete by partition key - delete from ks.table where pk = id delete by range - delete from ks.table where pk = id
TAG : cassandra
Date : October 02 2020, 09:00 AM , By : Jignesh Parekh
IN CASSANDRA, not able to create table with precision and scale values
IN CASSANDRA, not able to create table with precision and scale values
Any of those help In Cassandra, you do not specify the precision of decimals or lengths of varchars. See https://docs.datastax.com/en/dse/5.1/cql/cql/cql_reference/refDataTypes.html.You will also need to specify a primary key.
TAG : cassandra
Date : October 02 2020, 07:00 AM , By : Efe İzbudak
JanusGraph Not enough replicas available for query at consistency QUORUM
JanusGraph Not enough replicas available for query at consistency QUORUM
Hope this helps Obliviously there is a quorum operation going on. Seems like the configuration of cl=1 wasn't enough
TAG : cassandra
Date : October 01 2020, 10:00 PM , By : Champn
Is there any option in config of OpsCenter to automatically start repair service?
Is there any option in config of OpsCenter to automatically start repair service?
seems to work fine You can use OpsCenter's REST API to trigger repair service, particularly, you need this repair service API, that is just posting the time to completion to the /{cluster_id}/services/repair endpoint. For example, if your time to com
TAG : cassandra
Date : October 01 2020, 04:00 AM , By : Regadera
ScyllaDB / Cassandra higher replication factor than total number of nodes with CL=QUORUM
ScyllaDB / Cassandra higher replication factor than total number of nodes with CL=QUORUM
seems to work fine With RF=7, the data is always replicated to 7 nodes. When a node (or two) goes down, the rest of the five nodes already have a copy, and no additional streaming is required.Using CL=QUORUM, even three nodes down, will not hurt your
TAG : cassandra
Date : September 30 2020, 01:00 AM , By : A. Lawrence
In cassandra when to use decimal Vs float/double?
In cassandra when to use decimal Vs float/double?
Does that help I am using apache cassandra 3.x version. I am bit confused regarding when should I use decimal vs float types? , From the book Learning Apache Cassandra By Mat Brown:
TAG : cassandra
Date : September 29 2020, 10:00 AM , By : Joshua Velasco
Is RethinkDB a good fit for a generic Real-time aggregation platform?
Is RethinkDB a good fit for a generic Real-time aggregation platform?
To fix the issue you can do IMHO, RehinkDB is good fit in your use case. From RethinkDB docs
TAG : cassandra
Date : September 29 2020, 10:00 AM , By : Lapkonium
What is the equivalent of CQL count() in Java driver
What is the equivalent of CQL count() in Java driver
wish helps you Equivalent to count() in querybuilder is QueryBuilder.select().countAll(). I would instead just iterate through the resultSet and incrementing a counter as it will page through more slowly while count does some things internally that c
TAG : cassandra
Date : September 29 2020, 04:00 AM , By : Andrea Guitto
Is there a way to view data in 2 replicas in Cassandra?
Is there a way to view data in 2 replicas in Cassandra?
To fix the issue you can do So your question is not real clear "See the data in 2 replicas". If you ever want to validate your data, you can run some commands to visually see things.The first thing you'd want to do is log onto the node you want to in
TAG : cassandra
Date : September 28 2020, 07:00 PM , By : Pepe M
Cassandra Installation
Cassandra Installation
this will help Rolling back to version 3.11.4 fixed this issue. Check if you have edited the environment variable of CASSANDRA_HOME to point to version 3.11.4.
TAG : cassandra
Date : September 27 2020, 08:00 PM , By : A.Devismes
can we use more than one cassandra CQL collections ( set,list,map )in a single query?
can we use more than one cassandra CQL collections ( set,list,map )in a single query?
fixed the issue. Will look into that further Of course you can, with some adjustments:1) It helps if the type of a column isn't linked to the column name by an underscore. Instead of:
TAG : cassandra
Date : September 27 2020, 05:00 PM , By : pgs
How write in cassandra works in terms of commitlog_segment_size_in_mb?
How write in cassandra works in terms of commitlog_segment_size_in_mb?
wish helps you This warning is issued when one mutation is greater than half of the commitlog_segment_size_in_mb. Mutation in Cassandra is a single change in data, and may correspond to one or more changes to the same partition (insert/delete/update)
TAG : cassandra
Date : September 27 2020, 07:00 AM , By : Toki Tahmid Inan
default consistency level and quorum setting in Cassandra and what is the best practice for tuning them
default consistency level and quorum setting in Cassandra and what is the best practice for tuning them
To fix this issue Default READ and WRITE consistency is ONE in cassandra.Consistency can be specified for each query. CONSISTENCY command can be used from cqlsh to check current consistency value or set new consistency value.
TAG : cassandra
Date : September 27 2020, 02:00 AM , By : N Kap
Is it possible to set default time to live for existing Cassandra table and also apply this TTL to all the existing reco
Is it possible to set default time to live for existing Cassandra table and also apply this TTL to all the existing reco
hop of those help? You can set a default TTL for the table, but there is no way to go back and change a record without a TTL to have a TTL (i.e. the default TTL will apply a TTL value to a record that does not have one during insert time). In your ca
TAG : cassandra
Date : September 26 2020, 08:00 AM , By : Baraa
Canssandra replication within different data centers
Canssandra replication within different data centers
I hope this helps you . Yes, it should be possible declaring them as two different datacenters. Cassandra allows you to have different replication factors depending on the DC used:
TAG : cassandra
Date : September 26 2020, 05:00 AM , By : RAJU
Scylla DB: SELECT (*) times out on empty table
Scylla DB: SELECT (*) times out on empty table
wish helps you Do you see any load to CPU, IO, Network while having these long CQL executing? see https://docs.scylladb.com/troubleshooting/report_scylla_problem/report-a-performance-problem You can compare stats from nodetool cfstats https://docs.sc
TAG : cassandra
Date : September 25 2020, 02:00 PM , By : Miguel Luque
How to enable G1 gc in apache cassandra 3.11.4
How to enable G1 gc in apache cassandra 3.11.4
this one helps. So that's happening because CMS is the default garbage collector in Java 8. Even if you comment it out, unless you've added the G1 settings, it's still going to use CMS.In between the CMS and GC Logging sections, there should be one m
TAG : cassandra
Date : September 22 2020, 12:00 PM , By : fadli robbi
What should I use for localDataCenter in Cassandra-Driver 4.x
What should I use for localDataCenter in Cassandra-Driver 4.x
To fix the issue you can do To find your datacenter name, check in your node's cassandra-rackdc.properties file:
TAG : cassandra
Date : September 22 2020, 07:00 AM , By : Kirk
Cassandra Authentication Fail: "Unable to perform authentication: Cannot achieve consistency level QUORUM"
Cassandra Authentication Fail: "Unable to perform authentication: Cannot achieve consistency level QUORUM"
wish helps you My guess is that you need to run repair on all of the nodes for the "system_auth", and if you're running DSE, ensure any keyspace that starts with "dse" that has "simple strategy" is updated to Network Topology Strategy with appropriat
TAG : cassandra
Date : September 20 2020, 07:00 AM , By : Uchechukwu Onuoha
Cassandra consistency issue when node dies/offline in between transaction
Cassandra consistency issue when node dies/offline in between transaction
may help you . Yes, you are correct.In the case a read repair runs for that record, the data will be replicated from n3. This will depend on your configuration of read_repair_chance and how often the record is queried.
TAG : cassandra
Date : September 19 2020, 08:00 PM , By : Showstopper
Getting error for value exceeding max_value_size_in_mb in cassandra.yaml
Getting error for value exceeding max_value_size_in_mb in cassandra.yaml
To fix this issue Now I observed some errors on my Cassandra system.log/debug.log and node was sudden DOWN after below errors. , What does it mean by this value?
TAG : cassandra
Date : September 16 2020, 03:00 PM , By : Daniel Shen
Cassandra Insert/Update without duplication when you can't rely on the primary key or uuid
Cassandra Insert/Update without duplication when you can't rely on the primary key or uuid
it helps some times You can only really use the UUID as the partition key if you know if beforehand. You won't be able to insert new customers into the table if you don't have the UUID.Based on your description, you use the UUID as the unique ID for
TAG : cassandra
Date : September 15 2020, 06:00 PM , By : daisy123
What is the difference between scylla read path and cassandra read path?
What is the difference between scylla read path and cassandra read path?
may help you . There can be various reasons why you are not getting the most out of your Scylla Cluster.
TAG : cassandra
Date : September 14 2020, 07:00 AM , By : Lars Cawley
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