nodetool toppartitions

Samples the activity in a table during the specified duration and reports the most active partitions.

For each sampler, nodetool toppartitions reports:

Cardinality

The number of unique operations in the sample set.
The <n> partitions

The number of partitions in the specified table that had the most traffic in the specified time period, where <n> is the value of the -k argument or ten if -k is not explicitly set in the command.

Partition

Partition

The partition key.

Count

The number of operations of the specified type that occurred during the specified time period.

+/-

The margin of error for the Count statistic.

To keep the toppartitions reporting from slowing performance, the database does not keep an exact count of operations, but uses sampling techniques to create an approximate number. (This example reports on a sample cluster; a production system might generate millions of reads or writes in a few seconds.) The +/- figure allows you to judge the accuracy of the toppartitions reporting.

Synopsis

nodetool [<connection_options>] toppartitions
[-a <reads> | -a <writes>] [-k <num_partitions>] [-s <size>] [--]
<keyspace_name> <table_name> <duration>

Syntax conventions Description

Syntax conventions	Description
UPPERCASE	Literal keyword.
Lowercase	Not literal.
<`Italics>`	Variable value. Replace with a valid option or user-defined value.
`[ ]`	Optional. Square brackets ( `[ ]` ) surround optional command arguments. Do not type the square brackets.
`( )`	Group. Parentheses ( `( )` ) identify a group to choose from. Do not type the parentheses.
`\|`	Or. A vertical bar ( `\|` ) separates alternative elements. Type any one of the elements. Do not type the vertical bar.
`...`	Repeatable. An ellipsis ( `...` ) indicates that you can repeat the syntax element as often as required.
`'<Literal string>'`	Single quotation ( `'` ) marks must surround literal strings in CQL statements. Use single quotation marks to preserve upper case.
`{ <key>:<value> }`	Map collection. Braces ( `{ }` ) enclose map collections or key value pairs. A colon separates the key and the value.
`<<datatype1>,<datatype2>>`	Set, list, map, or tuple. Angle brackets ( `< >` ) enclose data types in a set, list, map, or tuple. Separate the data types with a comma.
`cql_statement;`	End CQL statement. A semicolon ( `;` ) terminates all CQL statements.
`[ -- ]`	Separate the command line options from the command arguments with two hyphens ( `--` ). This syntax is useful when arguments might be mistaken for command line options.
`' <<schema> ... </schema> >'`	Search CQL only: Single quotation marks ( `'` ) surround an entire XML schema declaration.
`@<xml_entity>='<xml_entity_type>'`	Search CQL only: Identify the entity and literal value to overwrite the XML element in the schema and solrconfig files.

UPPERCASE

Literal keyword.

Lowercase

Not literal.

<`Italics>`

Variable value. Replace with a valid option or user-defined value.

[ ]

Optional. Square brackets ( [ ] ) surround optional command arguments. Do not type the square brackets.

( )

Group. Parentheses ( ( ) ) identify a group to choose from. Do not type the parentheses.

|

Or. A vertical bar ( | ) separates alternative elements. Type any one of the elements. Do not type the vertical bar.

...

Repeatable. An ellipsis ( ... ) indicates that you can repeat the syntax element as often as required.

'<Literal string>'

Single quotation ( ' ) marks must surround literal strings in CQL statements. Use single quotation marks to preserve upper case.

{ <key>:<value> }

Map collection. Braces ( { } ) enclose map collections or key value pairs. A colon separates the key and the value.

<<datatype1>,<datatype2>>

Set, list, map, or tuple. Angle brackets ( < > ) enclose data types in a set, list, map, or tuple. Separate the data types with a comma.

cql_statement;

End CQL statement. A semicolon ( ; ) terminates all CQL statements.

[ -- ]

Separate the command line options from the command arguments with two hyphens ( -- ). This syntax is useful when arguments might be mistaken for command line options.

' <<schema> ... </schema> >'

Search CQL only: Single quotation marks ( ' ) surround an entire XML schema declaration.

@<xml_entity>='<xml_entity_type>'

Search CQL only: Identify the entity and literal value to overwrite the XML element in the schema and solrconfig files.

Definition

The short- and long-form options are comma-separated.

Connection options

-h, --host hostname: The hostname or IP address of a remote node or nodes. When omitted, the default is the local machine.
-p, --port jmx_port: The JMX port number.
-pw, --password jmxpassword: The JMX password for authenticating with secure JMX. If a password is not provided, you are prompted to enter one.
-pwf, --password-file jmx_password_filepath: The filepath to the file that stores JMX authentication credentials.
-u, --username jmx_username: The username for authenticating with secure JMX.

Command arguments

--: Separates an option from an argument that could be mistaken for an option.

-a samplers: Sampler to use. Available options are <reads> or <writes>.

duration: Duration in milliseconds.

-k num_partitions: Number of top partitions. Default is 10.

keyspace_name: The keyspace name.

-s size: Capacity of stream summary. A value closer to actual cardinality of partitions yields more accurate results. Default is 256.

table_name: The table name.

Examples

Sample the most active partitions for the cyclist_id table in the cycling keyspace for 1,000 milliseconds.

nodetool toppartitions cycling cyclist_id 1000

Results:

Keyspace/table: cycling/cyclist_id
READS Sampler:
  Cardinality: ~3 (256 capacity)
  Top 4 partitions:
    Partition                Count       +/-
    4d4e30314f374e313730        42        41
    4f363735324e324e4d30        42        41
    303535324e4b4d504c30        42        41
    4e355030324e344d3030        41        40

WRITES Sampler:
  Cardinality: ~2 (256 capacity)
  Top 4 partitions:
    Partition                Count       +/-
    4b504d39354f37353131        15        14
    3738313134394d353530        15        14
    4f363735324e324e4d30        15        14
    303535324e4b4d504c30        15        14

Sample the most active two partitions for writes in the cyclist_id table in the cycling keyspace for 1,000 milliseconds.

nodetool toppartitions -a writes -k 2 cycling cyclist_id 1000