CQLSh: the CQL shell

cqlsh is a command line shell for interacting with Cassandra through CQL (the Cassandra Query Language). It is shipped with every Cassandra package, and can be found in the bin/ directory alongside the cassandra executable. cqlsh utilizes the Python native protocol driver, and connects to the single node specified on the command line.

Compatibility

cqlsh is compatible with Python 2.7.

In general, a given version of cqlsh is only guaranteed to work with the version of Cassandra that it was released with. In some cases, cqlsh make work with older or newer versions of Cassandra, but this is not officially supported.

Optional Dependencies

cqlsh ships with all essential dependencies. However, there are some optional dependencies that can be installed to improve the capabilities of cqlsh.

pytz

By default, cqlsh displays all timestamps with a UTC timezone. To support display of timestamps with another timezone, the pytz library must be installed. See the timezone option in cqlshrc for specifying a timezone to use.

cython

The performance of cqlsh’s COPY operations can be improved by installing cython. This will compile the python modules that are central to the performance of COPY.

cqlshrc

The cqlshrc file holds configuration options for cqlsh. By default this is in the user’s home directory at ~/.cassandra/cqlsh, but a custom location can be specified with the --cqlshrc option.

Example config values and documentation can be found in the conf/cqlshrc.sample file of a tarball installation. You can also view the latest version of cqlshrc online.

Command Line Options

Usage:

cqlsh [options] [host [port]]

Options:

-C --color
Force color output
--no-color
Disable color output
--browser
Specify the browser to use for displaying cqlsh help. This can be one of the supported browser names (e.g. firefox) or a browser path followed by %s (e.g. /usr/bin/google-chrome-stable %s).
--ssl
Use SSL when connecting to Cassandra
-u --user
Username to authenticate against Cassandra with
-p --password
Password to authenticate against Cassandra with, should be used in conjunction with --user
-k --keyspace
Keyspace to authenticate to, should be used in conjunction with --user
-f --file
Execute commands from the given file, then exit
--debug
Print additional debugging information
--encoding
Specify a non-default encoding for output (defaults to UTF-8)
--cqlshrc
Specify a non-default location for the cqlshrc file
-e --execute
Execute the given statement, then exit
--connect-timeout
Specify the connection timeout in seconds (defaults to 2s)
--request-timeout
Specify the request timeout in seconds (defaults to 10s)
-t --tty
Force tty mode (command prompt)

Special Commands

In addition to supporting regular CQL statements, cqlsh also supports a number of special commands that are not part of CQL. These are detailed below.

CONSISTENCY

Usage: CONSISTENCY <consistency level>

Sets the consistency level for operations to follow. Valid arguments include:

- ANY
- ONE
- TWO
- THREE
- QUORUM
- ALL
- LOCAL_QUORUM
- LOCAL_ONE
- SERIAL
- LOCAL_SERIAL

SERIAL CONSISTENCY

Usage: SERIAL CONSISTENCY <consistency level>

Sets the serial consistency level for operations to follow. Valid arguments include:

  • SERIAL
  • LOCAL_SERIAL

The serial consistency level is only used by conditional updates (INSERT, UPDATE and DELETE with an IF condition). For those, the serial consistency level defines the consistency level of the serial phase (or “paxos” phase) while the normal consistency level defines the consistency for the “learn” phase, i.e. what type of reads will be guaranteed to see the update right away. For example, if a conditional write has a consistency level of QUORUM (and is successful), then a QUORUM read is guaranteed to see that write. But if the regular consistency level of that write is ANY, then only a read with a consistency level of SERIAL is guaranteed to see it (even a read with consistency ALL is not guaranteed to be enough).

SHOW VERSION

Prints the cqlsh, Cassandra, CQL, and native protocol versions in use. Example:

cqlsh> SHOW VERSION
[cqlsh 5.0.1 | Cassandra 3.8 | CQL spec 3.4.2 | Native protocol v4]

SHOW HOST

Prints the IP address and port of the Cassandra node that cqlsh is connected to in addition to the cluster name. Example:

cqlsh> SHOW HOST
Connected to Prod_Cluster at 192.0.0.1:9042.

SHOW SESSION

Pretty prints a specific tracing session.

Usage: SHOW SESSION <session id>

Example usage:

cqlsh> SHOW SESSION 95ac6470-327e-11e6-beca-dfb660d92ad8

Tracing session: 95ac6470-327e-11e6-beca-dfb660d92ad8

 activity                                                  | timestamp                  | source    | source_elapsed | client
-----------------------------------------------------------+----------------------------+-----------+----------------+-----------
                                        Execute CQL3 query | 2016-06-14 17:23:13.979000 | 127.0.0.1 |              0 | 127.0.0.1
 Parsing SELECT * FROM system.local; [SharedPool-Worker-1] | 2016-06-14 17:23:13.982000 | 127.0.0.1 |           3843 | 127.0.0.1
...

SOURCE

Reads the contents of a file and executes each line as a CQL statement or special cqlsh command.

Usage: SOURCE <string filename>

Example usage:

cqlsh> SOURCE '/home/thobbs/commands.cql'

CAPTURE

Begins capturing command output and appending it to a specified file. Output will not be shown at the console while it is captured.

Usage:

CAPTURE '<file>';
CAPTURE OFF;
CAPTURE;

That is, the path to the file to be appended to must be given inside a string literal. The path is interpreted relative to the current working directory. The tilde shorthand notation ('~/mydir') is supported for referring to $HOME.

Only query result output is captured. Errors and output from cqlsh-only commands will still be shown in the cqlsh session.

To stop capturing output and show it in the cqlsh session again, use CAPTURE OFF.

To inspect the current capture configuration, use CAPTURE with no arguments.

HELP

Gives information about cqlsh commands. To see available topics, enter HELP without any arguments. To see help on a topic, use HELP <topic>. Also see the --browser argument for controlling what browser is used to display help.

TRACING

Enables or disables tracing for queries. When tracing is enabled, once a query completes, a trace of the events during the query will be printed.

Usage:

TRACING ON
TRACING OFF

PAGING

Enables paging, disables paging, or sets the page size for read queries. When paging is enabled, only one page of data will be fetched at a time and a prompt will appear to fetch the next page. Generally, it’s a good idea to leave paging enabled in an interactive session to avoid fetching and printing large amounts of data at once.

Usage:

PAGING ON
PAGING OFF
PAGING <page size in rows>

EXPAND

Enables or disables vertical printing of rows. Enabling EXPAND is useful when many columns are fetched, or the contents of a single column are large.

Usage:

EXPAND ON
EXPAND OFF

LOGIN

Authenticate as a specified Cassandra user for the current session.

Usage:

LOGIN <username> [<password>]

EXIT

Ends the current session and terminates the cqlsh process.

Usage:

EXIT
QUIT

CLEAR

Clears the console.

Usage:

CLEAR
CLS

DESCRIBE

Prints a description (typically a series of DDL statements) of a schema element or the cluster. This is useful for dumping all or portions of the schema.

Usage::

 DESCRIBE CLUSTER
 DESCRIBE SCHEMA
 DESCRIBE KEYSPACES
 DESCRIBE KEYSPACE <keyspace name>
 DESCRIBE TABLES
 DESCRIBE TABLE <table name>
 DESCRIBE MATERIALIZED VIEW <view name>
 DESCRIBE TYPES
 DESCRIBE TYPE <type name>
 DESCRIBE FUNCTIONS
 DESCRIBE FUNCTION <function name>
 DESCRIBE AGGREGATES
 DESCRIBE AGGREGATE <aggregate function name>

In any of the commands, DESC may be used in place of DESCRIBE.

The DESCRIBE CLUSTER command prints the cluster name and partitioner:

cqlsh> DESCRIBE CLUSTER

Cluster: Test Cluster
Partitioner: Murmur3Partitioner

The DESCRIBE SCHEMA command prints the DDL statements needed to recreate the entire schema. This is especially useful for dumping the schema in order to clone a cluster or restore from a backup.

COPY TO

Copies data from a table to a CSV file.

Usage::

 COPY <table name> [(<column>, ...)] TO <file name> WITH <copy option> [AND <copy option> ...]

If no columns are specified, all columns from the table will be copied to the CSV file. A subset of columns to copy may be specified by adding a comma-separated list of column names surrounded by parenthesis after the table name.

The <file name> should be a string literal (with single quotes) representing a path to the destination file. This can also the special value STDOUT (without single quotes) to print the CSV to stdout.

See Shared COPY Options for options that apply to both COPY TO and COPY FROM.

Options for COPY TO

MAXREQUESTS
The maximum number token ranges to fetch simultaneously. Defaults to 6.
PAGESIZE
The number of rows to fetch in a single page. Defaults to 1000.
PAGETIMEOUT
By default the page timeout is 10 seconds per 1000 entries in the page size or 10 seconds if pagesize is smaller.
BEGINTOKEN, ENDTOKEN
Token range to export. Defaults to exporting the full ring.
MAXOUTPUTSIZE
The maximum size of the output file measured in number of lines; beyond this maximum the output file will be split into segments. -1 means unlimited, and is the default.
ENCODING
The encoding used for characters. Defaults to utf8.

COPY FROM

Copies data from a CSV file to table.

Usage::

 COPY <table name> [(<column>, ...)] FROM <file name> WITH <copy option> [AND <copy option> ...]

If no columns are specified, all columns from the CSV file will be copied to the table. A subset of columns to copy may be specified by adding a comma-separated list of column names surrounded by parenthesis after the table name.

The <file name> should be a string literal (with single quotes) representing a path to the source file. This can also the special value STDIN (without single quotes) to read the CSV data from stdin.

See Shared COPY Options for options that apply to both COPY TO and COPY FROM.

Options for COPY FROM

INGESTRATE
The maximum number of rows to process per second. Defaults to 100000.
MAXROWS
The maximum number of rows to import. -1 means unlimited, and is the default.
SKIPROWS
A number of initial rows to skip. Defaults to 0.
SKIPCOLS
A comma-separated list of column names to ignore. By default, no columns are skipped.
MAXPARSEERRORS
The maximum global number of parsing errors to ignore. -1 means unlimited, and is the default.
MAXINSERTERRORS
The maximum global number of insert errors to ignore. -1 means unlimited. The default is 1000.
ERRFILE =
A file to store all rows that could not be imported, by default this is import_<ks>_<table>.err where <ks> is your keyspace and <table> is your table name.
MAXBATCHSIZE
The max number of rows inserted in a single batch. Defaults to 20.
MINBATCHSIZE
The min number of rows inserted in a single batch. Defaults to 2.
CHUNKSIZE
The number of rows that are passed to child worker processes from the main process at a time. Defaults to 1000.

Shared COPY Options

Options that are common to both COPY TO and COPY FROM.

NULLVAL
The string placeholder for null values. Defaults to null.
HEADER
For COPY TO, controls whether the first line in the CSV output file will contain the column names. For COPY FROM, specifies whether the first line in the CSV input file contains column names. Defaults to false.
DECIMALSEP
The character that is used as the decimal point separator. Defaults to ..
THOUSANDSSEP
The character that is used to separate thousands. Defaults to the empty string.
BOOLSTYlE
The string literal format for boolean values. Defaults to True,False.
NUMPROCESSES
The number of child worker processes to create for COPY tasks. Defaults to a max of 4 for COPY FROM and 16 for COPY TO. However, at most (num_cores - 1) processes will be created.
MAXATTEMPTS
The maximum number of failed attempts to fetch a range of data (when using COPY TO) or insert a chunk of data (when using COPY FROM) before giving up. Defaults to 5.
REPORTFREQUENCY
How often status updates are refreshed, in seconds. Defaults to 0.25.
RATEFILE
An optional file to output rate statistics to. By default, statistics are not output to a file.

See also:

Apache Cassandra Query Language

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