cbc-n1qlback - Man Page

Stress Test for Couchbase Query (N1QL)

Synopsis

cbc-n1qlback -f QUERYFILE [Options]

Description

cbc-n1qlback creates a specified number of threads each executing a set of user defined queries.

cbc-n1qlback requires that it be passed the path to a file containing the queries to execute; one per line. The query should be in the format of the actual HTTP POST body (in JSON format) to be sent to the server. For simple queries, only the statement field needs to be set:

{"statement":"SELECT country FROM `travel-sample`"}
{"statement":"SELECT country, COUNT(country) FROM `travel-sample` GROUP BY country"}

For more complex queries (for example, placeholders, custom options), you may refer to the N1QL REST API reference.

For example, the following line shows how to use named parameter

{"statement":"SELECT RAW meta().id FROM `travel-sample` WHERE type=$type LIMIT 1", "$type":"airline"}

There is also special query option, "n1qlback", which is stripped before sending the payload. Currently it allows to tell if the particular query must be prepared before execution:

{"statement":"SELECT * FROM `travel-sample` WHERE type=$type LIMIT 10", "$type":"airline", "n1qlback": {"prepare": true}}

n1qlback requires that any resources (data items, indexes) are already defined.

Options

The following options control workload generation:

-f --queryfile=PATH

Path to a file containing the query bodies to execute in JSON format, one query per line. See above for the format.

-t,  --num-threads=NTHREADS

Set the number of threads (and thus the number of client instances) to run concurrently. Each thread is assigned its own client object.

The following options control how cbc-n1qlback connects to the cluster

-U,  --spec=SPEC

A string describing the cluster to connect to. The string is in a URI-like syntax, and may also contain other options. See the Examples section for information. Typically such a URI will look like couchbase://host1,host2,host3/bucket.

The default for this option is couchbase://localhost/default

-u,  --username=USERNAME

Specify the username for the bucket. Since Couchbase 5.x this is mandatory switch, and it must specify the name of the user exisiting on cluster (read more at "Security/Authorization" section of the server manual). For older servers this field should be either left empty or set to the name of the bucket itself.

-P,  --password=PASSWORD:
-P -, --password=-

Specify the password for the bucket. As for servers before 5.x this was only needed if the bucket is protected with a password. For cluster version after 5.x, the password is mandatory, and should match the selected account (read more at "Security/Authorization" section of the server manual).

Specifying the - as the password indicates that the program should prompt for the password. You may also specify the password on the commandline, directly, but is insecure as command line arguments are visible via commands such as ps.

-T,  --timings

Dump command timings at the end of execution. This will display a histogram showing the latencies for the commands executed.

-v,  --verbose

Specify more information to standard error about what the client is doing. You may specify this option multiple times for increased output detail.

-D,  --cparam=OPTION=VALUE

Provide additional client options. Acceptable options can also be placed in the connection string, however this option is provided as a convenience. This option may be specified multiple times, each time specifying a key=value pair (for example, -Doperation_timeout=10 -Dconfig_cache=/foo/bar/baz). See Additional Options for more information

-y,  --compress

Enable compressing of documents. When the library is compiled with compression support, this option will enable Snappy compression for outgoing data. Incoming compressed data handled automatically regardless of this option. Note, that because the compression support have to be negotiated with the server, first packets might be sent uncompressed even when this switch was specified. This is because the library might queue data commands before socket connection has been established, and the library will negotiate compression feature. If it is known that all server support compression repeating the switch (like -yy) will force compression for all outgoing mutations, even scheduled before establishing connection.

--truststorepath=PATH

The path to the server´s SSL certificate. This is typically required for SSL connectivity unless the certificate has already been added to the OpenSSL installation on the system (only applicable with couchbases:// scheme)

--certpath=PATH

The path to the server´s SSL certificate. This is typically required for SSL connectivity unless the certificate has already been added to the OpenSSL installation on the system (only applicable with couchbases:// scheme). This also should contain client certificate when certificate authentication used, and in this case other public certificates could be extracted into truststorepath chain.

--keypath=PATH

The path to the client SSL private key. This is typically required for SSL client certificate authentication. The certificate itself have to go first in chain specified by certpath (only applicable with couchbases:// scheme)

--dump

Dump verbose internal state after operations are done.

-e,  --error-log=PATH

Path to a file, where the command will write failed queries along with error details. Use this option to figure out why ERRORS metric is not zero.

Additional Options

The following options may be included in the connection string (via the -U option) as URI-style query params (e.g. couchbase://host/bucket?option1=value1&option2=value2) or as individual key=value pairs passed to the -D switch (e.g. -Doption1=value1 -Doption2=value). The -D will internally build the connection string, and is provided as a convenience for options to be easily passed on the command-line

Examples

The following will create a file with 3 queries and 5 threads alternating between them. It also creates indexes on the travel-sample bucket

cbc n1ql ´CREATE INDEX ix_name ON `travel-sample`(name)´
cbc n1ql ´CREATE INDEX ix_country ON `travel-sample`(country)´

Crete text file queries.txt with the following content (note that fourth query has parameter)

{"statement":"SELECT country FROM `travel-sample` WHERE `travel-sample`.country = \"United States\""}
{"statement":"SELECT name FROM `travel-sample` LIMIT 10"}
{"statement":"SELECT country, COUNT(country) FROM `travel-sample` GROUP BY country"}
{"statement":"SELECT RAW meta().id FROM `travel-sample` WHERE type=$type LIMIT 1", "$type":"airline", "n1qlback": {"prepare": true}}

Run the test load

cbc-n1qlback --num-threads 5 --queryfile queries.txt

Bugs

This command´s options are subject to change.

See Also

cbc(1), cbc-pillowfight(1), cbcrc(4)

History

The cbc-n1qlback tool was first introduced in libcouchbase 2.4.10

Info

December 2020