This interpreter is compatible with any CQL statement supported by Cassandra. Ex:
INSERT INTO users(login,name) VALUES('jdoe','John DOE'); SELECT * FROM users WHERE login='jdoe';
USE spark_demo; SELECT * FROM albums_by_country LIMIT 1; SELECT * FROM countries LIMIT 1; SELECT * FROM artists WHERE login='jlennon';
BEGIN BATCH INSERT INTO users(login,name) VALUES('jdoe','John DOE'); INSERT INTO users_preferences(login,account_type) VALUES('jdoe','BASIC'); APPLY BATCH; CREATE TABLE IF NOT EXISTS test( key int PRIMARY KEY, value text );
INSERT INTO users(login,name) VALUES('jdoe','John DOE'); Insert into users(login,name) vAlues('hsue','Helen SUE');
Cassandra version | Documentation |
---|---|
2.2 | http://docs.datastax.com/en/cql/3.3/cql/cqlIntro.html |
2.1 & 2.0 | http://docs.datastax.com/en/cql/3.1/cql/cql_intro_c.html |
1.2 | http://docs.datastax.com/en/cql/3.0/cql/aboutCQL.html |
It is possible to add comments between statements. Single line comments start with the
hash sign (#). Multi-line comments are enclosed between
/** and **/. Ex:
#First comment INSERT INTO users(login,name) VALUES('jdoe','John DOE'); /** Multi line comments **/ Insert into users(login,name) vAlues('hsue','Helen SUE');
The interpreters is shipped with a built-in syntax validator. This validator only
checks for basic syntax errors. All CQL-related syntax validation is delegated
directly to Cassandra
Most of the time, syntax errors are due to missing semi-colons between statements or typo errors.
To make schema discovery easier and more interactive, the following commands are supported:
Command | Description |
---|---|
DESCRIBE CLUSTER; | Show the current cluster name and its partitioner |
DESCRIBE KEYSPACES; | List all existing keyspaces in the cluster and their configuration (replication factor, durable write ...) |
DESCRIBE TABLES; | List all existing keyspaces in the cluster and for each, all the tables name |
DESCRIBE KEYSPACE <keyspace name>; | Describe the given keyspace configuration and all its table details (name, columns, ...) |
DESCRIBE TABLE (<keyspace name>).<table name>; | Describe the given table. If the keyspace is not provided, the current logged in keyspace is used. If there is no logged in keyspace, the default system keyspace is used. If no table is found, an error message is raised |
DESCRIBE TYPE (<keyspace name>).<type name>; | Describe the given type(UDT). If the keyspace is not provided, the current logged in keyspace is used. If there is no logged in keyspace, the default system keyspace is used. If no type is found, an error message is raised |
The schema objects (cluster, keyspace, table & type) are displayed in a tabular format. There is a drop-down menu on the top left corner to expand objects details. On the top right menu is shown the Icon legend.
Sometimes you want to be able to pass runtime query parameters to your statements.
Those parameters are not part of the CQL specs and are specific to the interpreter.
Below is the list of all parameters:
Parameter | Syntax | Description |
---|---|---|
Consistency Level | @consistency=value | Apply the given consistency level to all queries in the paragraph |
Serial Consistency Level | @serialConsistency=value | Apply the given serial consistency level to all queries in the paragraph |
Timestamp | @timestamp=long value | Apply the given timestamp to all queries in the paragraph. Please note that timestamp value passed directly in CQL statement will override this value |
Retry Policy | @retryPolicy=value | Apply the given retry policy to all queries in the paragraph |
Fetch Size | @fetchSize=int value | Apply the given fetch size to all queries in the paragraph |
Parameter | Possible Values |
---|---|
Consistency Level | ALL, ANY, ONE, TWO, THREE, QUORUM, LOCAL_ONE, LOCAL_QUORUM, EACH_QUORUM |
Serial Consistency Level | SERIAL, LOCAL_SERIAL |
Timestamp | Any long value |
Retry Policy | DEFAULT, DOWNGRADING_CONSISTENCY, FALLTHROUGH, LOGGING_DEFAULT, LOGGING_DOWNGRADING, LOGGING_FALLTHROUGH |
Fetch Size | Any integer value |
CREATE TABLE IF NOT EXISTS spark_demo.ts( key int PRIMARY KEY, value text ); TRUNCATE spark_demo.ts; # Timestamp in the past @timestamp=10 # Force timestamp directly in the first insert INSERT INTO spark_demo.ts(key,value) VALUES(1,'first insert') USING TIMESTAMP 100; # Select some data to make the clock turn SELECT * FROM spark_demo.albums LIMIT 100; # Now insert using the timestamp parameter set at the beginning(10) INSERT INTO spark_demo.ts(key,value) VALUES(1,'second insert'); # Check for the result. You should see 'first insert' SELECT value FROM spark_demo.ts WHERE key=1;
For performance reason, it is better to prepare statements before-hand and reuse
them later by providing bound values. This interpreter provides 3 commands to handle prepared and
bound statements:
@prepare[statement_name]=... @bind[statement_name]=’text’, 1223, ’2015-07-30 12:00:01’, null, true, [‘list_item1’, ’list_item2’] @bind[statement_name_with_no_bound_value] @remove_prepare[statement_name]
You can use the syntax "@prepare[statement_name]=SELECT ..." to create a prepared statement.
The statement_name is mandatory because the interpreter prepares the given statement with the
Java driver and saves the generated prepared statement in an internal map, using the provided
statement_name as search key.
@prepare[select]=SELECT * FROM spark_demo.albums LIMIT ? @prepare[select]=SELECT * FROM spark_demo.artists LIMIT ?
Once the statement is prepared (possibly in a separated notebook/paragraph). You can bind values to it:
@bind[select_first]=10
BEGIN BATCH @bind[insert_user]='jdoe','John DOE' UPDATE users SET age = 27 WHERE login='hsue'; APPLY BATCH;
To avoid for a prepared statement to stay forever in the prepared statement map, you can use the @remove_prepare[statement_name] syntax to remove it. Removing a non-existing prepared statement yields no error.
Instead of hard-coding your CQL queries, it is possible to use the mustache syntax ({{ }})
to inject simple value or multiple choices forms.
The syntax for simple parameter is: {{input_Label=default value}}.
The default value is mandatory because the first time the paragraph is executed,
we launch the CQL query before rendering the form so at least one value should be provided.
The syntax for multiple choices parameter is: {{input_Label=value1 | value2 | … | valueN }}.
By default the first choice is used for CQL query the first time the paragraph is executed.
Example:
#Secondary index on performer style SELECT name, country, performer FROM spark_demo.performers WHERE name='{{performer=Sheryl Crow|Doof|Fanfarlo|Los Paranoia}}' AND styles CONTAINS '{{style=Rock}}';
Parameter | Default Value |
---|---|
cassandra.cluster | Test Cluster |
cassandra.compression.protocol | NONE, possible values: LZ4, SNAPPY |
cassandra.credentials.password | none |
cassandra.credentials.username | none |
cassandra.hosts | localhost |
cassandra.interpreter.parallelism | 10 |
cassandra.keyspace | system |
cassandra.load.balancing.policy | DEFAULT, or a FQCN of a custom class |
cassandra.max.schema.agreement.wait.second | 10 |
cassandra.native.port | 9042 |
cassandra.pooling.core.connection.per.host.local | Protocol V2 and below: 2, V3 and above: 1 |
cassandra.pooling.core.connection.per.host.remote | Protocol V2 and below: 1, V3 and above: 1 |
cassandra.pooling.heartbeat.interval.seconds | 30 |
cassandra.pooling.idle.timeout.seconds | Test Cluster |
cassandra.pooling.max.connection.per.host.local | Protocol V2 and below: 8, V3 and above: 1 |
cassandra.pooling.max.connection.per.host.remote | Protocol V2 and below: 2, V3 and above: 1 |
cassandra.pooling.max.request.per.connection.local | Protocol V2 and below: 128, V3 and above: 1024 |
cassandra.pooling.max.request.per.connection.remote | Protocol V2 and below: 128, V3 and above: 256 |
cassandra.pooling.new.connection.threshold.local | Protocol V2 and below: 100, V3 and above: 800 |
cassandra.pooling.new.connection.threshold.remote | Protocol V2 and below: 100, V3 and above: 200 |
cassandra.pooling.pool.timeout.millisecs | 5000 |
cassandra.protocol.version | 3 |
cassandra.query.default.consistency | ONE |
cassandra.query.default.fetchSize | 5000 |
cassandra.query.default.serial.consistency | SERIAL |
cassandra.reconnection.policy | DEFAULT, or a FQCN of a custom class |
cassandra.retry.policy | DEFAULT, or a FQCN of a custom class |
cassandra.socket.connection.timeout.millisecs | 500 |
cassandra.socket.read.timeout.millisecs | 12000 |
cassandra.socket.tcp.no_delay | true |
cassandra.speculative.execution.policy | DEFAULT, or a FQCN of a custom class |