I've got a cassandra table and want to delete a row, but only if one column has one specific value.
Even if cassandra claims that deleting succeeded (it returned "applied: true") the message will still be present.
Let's create the table and insert some data:
CREATE TABLE IF NOT EXISTS test
(
id uuid PRIMARY KEY,
recipient text,
message text
);
INSERT INTO test (id, recipient, message)
VALUES (7ee055ee-b5dd-4bfd-b184-614d51e268d5, 'felix', 'foo');
INSERT INTO test (id, recipient, message)
VALUES (86c9d632-dc24-4635-8277-c987c78bd242, 'andrew', 'bar');
Now I want to delete one message, but only if the user who requests the deletion (in this case felix) is the recipient and thus has permissions to do so:
cqlsh:service_message> DELETE FROM test WHERE id=7ee055ee-b5dd-4bfd-b184-614d51e268d5 IF recipient='felix';
[applied]
-----------
True
So I would now think that the query did succeed, but if we have a look at the table we'll see that the message still exists.
cqlsh:service_message> SELECT * FROM test;
id | message | recipient
--------------------------------------+---------+-----------
86c9d632-dc24-4635-8277-c987c78bd242 | bar | andrew
7ee055ee-b5dd-4bfd-b184-614d51e268d5 | foo | felix
(2 rows)
Some additional information:
cqlsh 5.0.1 | Cassandra 3.11.2 | CQL spec 3.4.4 | Native protocol v4
cqlsh> DESCRIBE KEYSPACE service_message
CREATE KEYSPACE service_message WITH replication = {'class': 'SimpleStrategy', 'replication_factor': '3'} AND durable_writes = true;
CREATE TABLE service_message.test (
id uuid PRIMARY KEY,
message text,
recipient text
) WITH bloom_filter_fp_chance = 0.01
AND caching = {'keys': 'ALL', 'rows_per_partition': 'NONE'}
AND comment = ''
AND compaction = {'class': 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy', 'max_threshold': '32', 'min_threshold': '4'}
AND compression = {'chunk_length_in_kb': '64', 'class': 'org.apache.cassandra.io.compress.LZ4Compressor'}
AND crc_check_chance = 1.0
AND dclocal_read_repair_chance = 0.1
AND default_time_to_live = 0
AND gc_grace_seconds = 864000
AND max_index_interval = 2048
AND memtable_flush_period_in_ms = 0
AND min_index_interval = 128
AND read_repair_chance = 0.0
AND speculative_retry = '99PERCENTILE';
INSERT and UPDATE statements using the IF clause support lightweight transactions .
From Datastax docs on CQL: https://docs.datastax.com/en/cql/3.3/cql/cql_using/useInsertLWT.html
I'm pretty sure deletes are not supported. If you want to effectively delete your information, you may consider setting the values of the cells in an UPDATE statement to null. Either by delete or by setting nulls, you are still creating tombstones.
I have created the keyspace and also created a table using Cassandra 3.0 server. I am using the 3 nodes architecture. And three of the servers are working and able to connect the 3 nodes. However when i insert or selecting the data using the CQL, Its showing the error saying that "NoHostAvailable:". Please could anyone provide me the reason and solution for this issue.
Topology
nodetool status output
UN 172.30.1.7 230.22 KB 256 ? 2103dcd3-f09b-47da-a187-bf28b42b918e rack1
DN 172.30.1.20 ? 256 ? 683db65d-0836-40e4-ab5b-fa0db20bae30 rack1
DN 172.30.1.2 ? 256 ? 2b1f15d1-2f92-41ef-a03e-0e5f5f578cf4 rack1
Schema
Keyspace
CREATE KEYSPACE test WITH REPLICATION = { 'class' : 'SimpleStrategy', 'replication_factor' : 2};
Table
CREATE TABLE testrep(id INT PRIMARY KEY);
Note that from nodetool status, 2 out of your 3 node cluster is down(DN).
You might be inserting with a Consistency Level that cannot be satisfied.
nodetool status
Datacenter: datacenter1
=======================
Status=Up/Down
|/ State=Normal/Leaving/Joining/Moving
-- Address Load Tokens Owns Host ID Rack
UN 127.0.0.1 237.31 MiB 256 ? 3c8a8d8d-992c-4b7c-a220-6951e37870c6 rack1
cassandra#cqlsh> create KEYSPACE qqq WITH replication = {'class': 'SimpleStrategy', 'replication_factor': 2};
cassandra#cqlsh> use qqq;
cassandra#cqlsh:qqq> CREATE TABLE testrep(id INT PRIMARY KEY);
cassandra#cqlsh:qqq> insert into testrep (id) VALUES ( 1);
cassandra#cqlsh:qqq> CONSISTENCY
Current consistency level is ONE.
cassandra#cqlsh:qqq> CONSISTENCY TWO ;
Consistency level set to TWO.
cassandra#cqlsh:qqq> insert into testrep (id) VALUES (2);
NoHostAvailable:
cassandra#cqlsh:qqq> exit
I have all keyspaces and tables copied from another cassandara data folder ,How can I restore it in my cassandara node.
I dont have snapshots which are normally required to restore.
You might be able to do this with the Cassandra Bulk Loader.
Assuming a packaged install (with default data and bin locations), try this from one of your nodes:
$ sstableloader -d hostname1,hostname2 /var/lib/cassandra/data/yourKeyspaceName/tableName/
Check out the documentation on the Bulk Loader for more details.
You can do this but:
You need to know the schema for all the tables you are restoring. If you don't know this, use sstable2json (example below, but this can be tricky and requires understanding how sstable2json formats things)
You will have to start a new node, create the keyspace and it's tables using the schema derived from 1 and then use the BulkLoader as described in the docs by Aaron (BryceAtNetwork23).
Example of retreiving a schema (an offline process) using sstable2json, this example assumes your keyspace name is test and the table is named example1:
sstable2json /var/lib/cassandra/data/test/example1-55639910d46a11e4b4335dbb0aaeeb24/test-example1-ka-1-Data.db
// output:
WARN 10:25:34 JNA link failure, one or more native method will be unavailable.
[
{"key": "7d700500-d46b-11e4-b433-5dbb0aaeeb24", <-- key = bytes of what is in the PRIMARY KEY()
"cells": [["coolguy:","",1427451885901681], <-- cql3 row marker (empty cell that tells us table was created using cql3)
["coolguy:age","29",1427451885901681], <-- age
["coolguy:email:_","coolguy:email:!",1427451885901680,"t",1427451885], <-- collection cell marker
["coolguy:email:6367406d61696c2e6e6574","",1427451885901681], <-- first entry in collection
["coolguy:email:636f6f6c677579383540676d61696c2e636f6d","",1427451885901681], <-- second entry in collection
["coolguy:password","xQajKe2fa?af",1427451885901681]]}, <-- another text field for password
{"key": "52641f40-d46b-11e4-b433-5dbb0aaeeb24",
"cells": [["lyubent:","",1427451813663728],
["lyubent:age","109",1427451813663728],
["lyubent:email:_","lyubent:email:!",1427451813663727,"t",1427451813],
["lyubent:email:66616b65406162762e6267","",1427451813663728],
["lyubent:email:66616b6540676d61696c2e636f6d","",1427451813663728],
["lyubent:password","password",1427451813663728]]}
]
The above equates to:
CREATE TABLE test.example1 (
id timeuuid,
username text,
age int,
email set<text>,
password text,
PRIMARY KEY (id, username)
) WITH CLUSTERING ORDER BY (username ASC)
// the below are settings that you have no way of knowing,
// unless you are hardcore enough to start digging through
// system tables with the debug tool, but this is beyond
// the scope of the question.
AND bloom_filter_fp_chance = 0.01
AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
AND comment = ''
AND compaction = {'min_threshold': '4', 'class': 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy', 'max_threshold': '32'}
AND compression = {'sstable_compression': 'org.apache.cassandra.io.compress.LZ4Compressor'}
AND dclocal_read_repair_chance = 0.1
AND default_time_to_live = 0
AND gc_grace_seconds = 864000
AND max_index_interval = 2048
AND memtable_flush_period_in_ms = 0
AND min_index_interval = 128
AND read_repair_chance = 0.0
AND speculative_retry = '99.0PERCENTILE';
You can see clearly that username and password get lost in the translation as they are the key, but you can tell that there is a compound key based on the fact that all cells have a section with : pre-appended, in the above two entries the examples are coolguy: and lyubent:. Going on this you know that they key is formed of PRIMARY KEY(something ?, username text). If you're lucky your primary key will be simple and debugging the schema from it will be straight forward, if not post it here and we'll see how far we can get.
I am using Cassandra 1.2.5 (cqlsh 3.0.2) and trying to inserting data in a small test-database with german characters which is not possible. I get back the message from cqlsh: "Bad Request: Input length = 1"
below is the setup of the keyspace, the table and the insert.
CREATE KEYSPACE test WITH REPLICATION = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 };
use test;
CREATE TABLE testdata (
id varchar,
text varchar,
PRIMARY KEY (id)
This is working:
insert into testdata (id, text) values ('4711', 'test');
This is not allowed:
insert into testdata (id, text) values ('4711', 'töst`);
->Bad Request: Input length = 1
my locale is :de_DE.UTF-8
Does Cassandra 1.2.5 has a problem with Umlaut ?
I just did what you posted and it worked for me. The one thing that was different however, is that instead of a single quote, you finished 'töst` with a backtick. That doesn't allow me to finish the statement in cqlsh. When I replace that with 'töst' it succeeds and I get:
cqlsh:test> select * from testdata;
id | text
------+------
4711 | töst
I'm not managing to execute a cql statement that should update the replication factor of a SimpleStrategy keyspace. It's annoying because this works fine with all three versions of CQLSH.
The keyspace context i'm using is set to use cqlv3
.setCqlVersion("3.0.0")
The cql:
"ALTER KEYSPACE \"" + ksContext.getKeyspaceName() + "\" WITH REPLICATION = { " +
"'class' : 'SimpleStrategy', 'replication_factor' : 3 };";
Stack trace:
InvalidRequestException(why:line 1:108 no viable alternative at character '}')
at com.netflix.astyanax.thrift.ThriftConverter.ToConnectionPoolException(ThriftConverter.java:159)
at com.netflix.astyanax.thrift.AbstractOperationImpl.execute(AbstractOperationImpl.java:60)
at com.netflix.astyanax.thrift.AbstractOperationImpl.execute(AbstractOperationImpl.java:27)
at com.netflix.astyanax.thrift.ThriftSyncConnectionFactoryImpl$1.execute(ThriftSyncConnectionFactoryImpl.java:140)
at com.netflix.astyanax.connectionpool.impl.AbstractExecuteWithFailoverImpl.tryOperation(AbstractExecuteWithFailoverImpl.java:69)
at com.netflix.astyanax.connectionpool.impl.AbstractHostPartitionConnectionPool.executeWithFailover(AbstractHostPartitionConnectionPool.java:255)
at com.netflix.astyanax.thrift.ThriftColumnFamilyQueryImpl$6.execute(ThriftColumnFamilyQueryImpl.java:694)
at smail.cli.astyanax.Astyanax.execCQL(Astyanax.java:75)
at smail.cli.astyanax.Astyanax.alterReplicationFactor(Astyanax.java:307)
at smail.cli.test.SchemaTest.alterReplicationFactor(SchemaTest.java:25)
at smail.cli.test.TestSuite.runTests(TestSuite.java:39)
at smail.cli.Main.main(Main.java:22)
Astyanax does have some problems with cql3 but its making great progress. Create a new keyspace and use CQLv2 (by setting it in the context) and try it without the " quotes:
String query = "ALTER KEYSPACE " + keyspaceName + " WITH REPLICATION = {
'class' : 'SimpleStrategy', 'replication_factor' : 2 };";
Note* in this query you are updating the rep factor to be 2.