kairosdb.md

KairosDB

• GitHub: https://github.com/kairosdb/kairosdb

Protocol

• Thrift
• CQL

Schema

• Thrift version
• CQL version

Metrics Schema

Keyspace

• NOTE: the replication_factor is 1, and it is a fixed number in CREATE_KEYSPACE in CassandraDatastore.java

CREATE KEYSPACE IF NOT EXISTS {{keyspace}}
  WITH REPLICATION = {
    'class' : 'SimpleStrategy',
    'replication_factor' : 1
  };

Metrics

• NOTE: it seems KairosDB has omitted keyspace when creating tables
• NOTE: column1 is not a typo, it might be the legacy problem of using Thrift protocol

CREATE TABLE IF NOT EXISTS data_points (
    key blob,
    column1 blob,
    value blob,
    PRIMARY KEY ((key), column1)
  ) WITH COMPACT STORAGE;

Row key index

• TODO: what is it used for, tags?

CREATE TABLE IF NOT EXISTS row_key_index (
    key blob,
    column1 blob,
    value blob,
    PRIMARY KEY ((key), column1)
  ) WITH COMPACT STORAGE;

Row key time index

• TODO: what is it used for
• NOTE: it does not use compact storage
  • TODO: why ...

CREATE TABLE IF NOT EXISTS row_key_time_index (
    metric text,
    row_time timestamp,
    value text,
    PRIMARY KEY ((metric), row_time)
  )

Row keys

• NOTE: no compact storage
• TODO: metric is text instead of blob
• TODO: what is frozen<map<text, text>>
• TODO: compound primary key? http://docs.datastax.com/en/cql/3.3/cql/cql_using/useCompoundPrimaryKey.html
• TODO: composite partition key https://docs.datastax.com/en/cql/3.1/cql/cql_reference/refCompositePk.html

CREATE TABLE IF NOT EXISTS row_keys (
    metric text,
    row_time timestamp,
    data_type text,
    tags frozen<map<text, text>>,
    value text,
    PRIMARY KEY ((metric, row_time), data_type, tags)
  )

String index

• TODO: what is it used for
• TODO: why they are similar, string_index, row_key_index, data_points

CREATE TABLE IF NOT EXISTS string_index (
    key blob,
    column1 blob,
    value blob,
    PRIMARY KEY ((key), column1)
  ) WITH COMPACT STORAGE

Meta Schema

Extra Schema