ycqlsh
Overview
The YCQL shell (ycqlsh) is a CLI for interacting with YugabyteDB using YCQL.
Note
The YCQL shell was previously namedcqlsh
. Although the cqlsh
binary is available in the bin
directory, it is deprecated and will be removed in a future release.
Installation
ycqlsh is installed as part of YugabyteDB and is located in the bin
directory of YugabyteDB home. You can also download it from the cqlsh GitHub repository.
If you prefer, you can install a standalone version using a shell script:
curl -sSL https://downloads.yugabyte.com/get_clients.sh | bash
If you have wget
, you can use the following:
wget -q -O - https://downloads.yugabyte.com/get_clients.sh | sh
Starting ycqlsh
./bin/ycqlsh
Connected to local cluster at 127.0.0.1:9042.
[ycqlsh 5.0.1 | Cassandra 3.9-SNAPSHOT | CQL spec 3.4.2 | Native protocol v4]
Use HELP for help.
ycqlsh>
Online help
Run ycqlsh --help
to display the online help.
Syntax
ycqlsh [flags] [host [port]]
Where
host
is the IP address of the host on which YB-TServer is run. The default is local host at127.0.0.1
.port
is the TCP port at which YB-TServer listens for YCQL connections. The default is9042
.
Example
./bin/ycqlsh --execute "select cluster_name, data_center, rack from system.local" 127.0.0.1
cluster_name | data_center | rack
---------------+-------------+-------
local cluster | datacenter1 | rack1
Flags
Flag | Short Form | Default | Description |
---|---|---|---|
--color |
-C |
Force color output. | |
--no-color |
Disable color output. | ||
--browser |
Specify the browser to use for displaying ycqlsh help. This can be one of the supported browser names (for example, Firefox) or a browser path followed by %s (for example, /usr/bin/google-chrome-stable %s ). |
||
--ssl |
Use SSL when connecting to YugabyteDB. | ||
--user |
-u |
Username to authenticate against YugabyteDB with. | |
--password |
-p |
Password to authenticate against YugabyteDB with, should be used in conjunction with --user . |
|
--keyspace |
-k |
Keyspace to authenticate to, should be used in conjunction with --user . |
|
--file |
-f |
Execute commands from the given file, then exit. | |
--debug |
Print additional debugging information. | ||
--encoding |
UTF-8 | Specify a non-default encoding for output. | |
--cqlshrc |
Specify the location for the cqlshrc file. The cqlshrc file holds configuration options for ycqlsh. By default this is in the user home directory at ~/.cassandra/cqlsh . |
||
--execute |
-e |
Execute the given statement, then exit. | |
--connect-timeout |
2 | Specify the connection timeout in seconds. | |
--request-timeout |
10 | Specify the request timeout in seconds. | |
--tty |
-t |
Force tty mode (command prompt). | |
--refresh_on_describe |
-r |
Force a refresh of the schema metadata on DESCRIBE. |
Save YCQL output to a file
To save output from a YCQL statement to a file, run the statement using the --execute flag, and redirect the output to a file.
For example, to save the output of a SELECT
statement:
./bin/ycqlsh -e "SELECT * FROM mytable" > output.txt
Special commands
In addition to supporting regular YCQL statements, ycqlsh also supports the following special commands.
CAPTURE
Captures command output and appends it to the specified file. Output is not shown at the console while it is captured.
CAPTURE '<file>'
CAPTURE OFF
CAPTURE
- 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
. - Captures query result output only. Errors and output from ycqlsh-only commands are still shown in the ycqlsh session.
- To stop capturing output and show it in the ycqlsh session again, use
CAPTURE OFF
. - To view the current capture configuration, use
CAPTURE
with no arguments.
CLEAR
Clears the console.
CLEAR
CLS
CONSISTENCY
CONSISTENCY <consistency level>
Sets the consistency level for the read operations that follow. Valid arguments include:
Consistency Level | Description |
---|---|
QUORUM |
Read the strongly consistent results from the tablet's quorum. The read request will be processed by the tablet leader only. This is the default consistency level. |
ONE |
Read from a follower with relaxed consistency guarantees. |
To view the current consistency level, use CONSISTENCY
with no arguments.
COPY FROM
Copies data from a CSV file to table.
COPY <table name> [(<column>, ...)] FROM <file name> WITH <copy flag> [AND <copy flag> ...]
By default, COPY FROM
copies all columns from the CSV file to the table. To copy a subset of columns, add a comma-separated list of column names enclosed in parentheses after the table name.
The file name
should be a string literal (with single quotes) representing a path to the source file. Use the special value STDIN
(without single quotes) to read the CSV data from stdin.
Flags | Default | Description |
---|---|---|
INGESTRATE |
100000 | The maximum number of rows to process per second. |
MAXROWS |
-1 | The maximum number of rows to import. -1 means unlimited. |
SKIPROWS |
0 | A number of initial rows to skip. |
SKIPCOLS |
A comma-separated list of column names to ignore. By default, no columns are skipped. | |
MAXPARSEERRORS |
-1 | The maximum global number of parsing errors to ignore. -1 means unlimited. |
MAXINSERTERRORS |
1000 | The maximum global number of insert errors to ignore. -1 means unlimited. |
ERRFILE= |
A file to store all rows that could not be imported; by default this is import_<ks>_<table>.err where <ks> is the keyspace and <table> is the table name. |
|
MAXBATCHSIZE |
20 | The max number of rows inserted in a single batch. |
MINBATCHSIZE |
2 | The min number of rows inserted in a single batch. |
CHUNKSIZE |
1000 | The number of rows that are passed to child worker processes from the main process at a time. |
See COPY TO
for additional flags common to both COPY TO
and COPY FROM
.
COPY TO
Copies data from a table to a CSV file.
COPY <table name> [(<column>, ...)] TO <file name> WITH <copy flag> [AND <copy flag> ...]
By default, COPY TO
copies all columns from the table to the CSV file. To copy a subset of columns, add a comma-separated list of column names enclosed in parentheses after the table name.
The file name
should be a string literal (with single quotes) representing a path to the destination file. You can also use the special value STDOUT
(without single quotes) to print the CSV to stdout.
Flags | Default | Description |
---|---|---|
MAXREQUESTS |
6 | The maximum number token ranges to fetch simultaneously. |
PAGESIZE |
1000 | The number of rows to fetch in a single page. |
PAGETIMEOUT |
10 | The timeout in seconds per 1000 entries in the page size or smaller. |
BEGINTOKEN , ENDTOKEN |
Token range to export. Defaults to exporting the full ring. | |
MAXOUTPUTSIZE |
-1 | 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. |
ENCODING |
utf8 | The encoding used for characters. |
The following flags are common to both COPY TO
and COPY FROM
.
Flags | Default | Description |
---|---|---|
NULLVAL |
null |
The string placeholder for null values. |
HEADER |
false |
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. |
DELIMITER |
, |
The character that is used to separate fields (columns). |
DECIMALSEP |
. |
The character that is used as the decimal point separator. |
THOUSANDSSEP |
The character that is used to separate thousands. Defaults to the empty string. | |
BOOLSTYlE |
True,False |
The string literal format for boolean values. |
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 |
5 | 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. |
REPORTFREQUENCY |
0.25 | How often status updates are refreshed, in seconds. |
RATEFILE |
An optional file to output rate statistics to. By default, statistics are not output to a file. |
DESCRIBE
Prints a description (typically a series of DDL statements) of a schema element or the cluster. Use DESCRIBE to dump all or portions of the schema.
DESCRIBE CLUSTER
DESCRIBE SCHEMA
DESCRIBE KEYSPACES
DESCRIBE KEYSPACE <keyspace name>
DESCRIBE TABLES
DESCRIBE TABLE <table name>
DESCRIBE INDEX <index name>
DESCRIBE TYPES
DESCRIBE TYPE <type name>
In any of the commands, DESC
may be used in place of DESCRIBE
.
The DESCRIBE CLUSTER
command prints the cluster name:
ycqlsh> DESCRIBE CLUSTER
Cluster: local cluster
The DESCRIBE SCHEMA
command prints the DDL statements needed to recreate the entire schema. Use this command to dump the schema; you can then use the resulting file to clone the cluster or restore from a backup.
EXIT
Ends the current session and terminates the ycqlsh process.
EXIT
QUIT
EXPAND
Enables or disables vertical printing of rows. Use EXPAND when fetching many columns, or the contents of a single column are large.
EXPAND ON
EXPAND OFF
To view the current expand setting, use EXPAND
with no arguments.
HELP
Gives information about ycqlsh 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.
HELP <topic>
LOGIN
Authenticate as a specified YugabyteDB user for the current session.
LOGIN <username> [<password>]
PAGING
Enables paging, disables paging, or sets the page size for read queries. When paging is enabled, only one page of data is fetched at a time and a prompt appears 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.
PAGING ON
PAGING OFF
PAGING <page size in rows>
To view the current paging setting, use PAGING
with no arguments.
SHOW HOST
Prints the IP address and port of the YB-TServer server that ycqlsh is connected to, and the cluster name. Example:
ycqlsh> SHOW HOST
Connected to local cluster at 127.0.0.1:9042.
SHOW VERSION
Prints the ycqlsh, Cassandra, CQL, and native protocol versions in use. Example:
ycqlsh> SHOW VERSION
[ycqlsh 5.0.1 | Cassandra 3.9-SNAPSHOT | CQL spec 3.4.2 | Native protocol v4]
SOURCE
Reads the contents of a file and executes each line as a YCQL statement or special ycqlsh command.
SOURCE '<file>'
Example:
ycqlsh> SOURCE '/home/yugabyte/commands.cql'
TIMING
Enables or disables basic request round-trip timing, as measured on a current YCQL shell session.
TIMING ON | OFF
TIMING ON: Enables round-trip timing for all further requests.
TIMING OFF: Disables timing.
TIMING (with no arguments): Outputs the current timing status.
Feature support
TIMING for SELECTs is available starting from YugabyteDB version 2.18.0.0 and later. TIMING will be available for all DMLs starting from YugabyteDB version 2.19.2.0 and later.Example
You can use TIMING and run queries from a YCQL session as follows:
ycqlsh> TIMING
Timing is currently disabled. Use TIMING ON to enable.
ycqlsh> TIMING ON
Now Timing is enabled
ycqlsh> use example;
26.18 milliseconds elapsed
ycqlsh:example> CREATE TABLE employees(department_id INT, employee_id INT,name TEXT, PRIMARY KEY(department_id, employee_id));
1042.67 milliseconds elapsed
ycqlsh:example> INSERT INTO employees(department_id, employee_id, name) VALUES (1, 1, 'John');
16.89 milliseconds elapsed
ycqlsh:example> INSERT INTO employees(department_id, employee_id, name) VALUES (1, 2, 'Jane');
11.65 milliseconds elapsed
ycqlsh:example> SELECT * FROM employees;
department_id | employee_id | name
---------------+-------------+------
1 | 1 | John
1 | 2 | Jane
5.76 milliseconds elapsed
(2 rows)
ycqlsh:example> TIMING OFF
Disabled Timing.