influxr_select: Selects data points from an InfluxDB database.

In influxr/influxr: An R interface to influxDB time series databases.

Description

'influxr_select' returns the result of a query.

Usage

influxr_select(
  client,
  database,
  measurement = "",
  fields = "*",
  from = NULL,
  to = NULL,
  tags = NULL,
  group_by = NULL,
  aggregation = NULL,
  fill = NULL,
  missing = c(-9999, -9999.99, -9999.9999),
  missing_replacement = NA,
  limit = 1e+06,
  desc = FALSE,
  extra_conditions = NULL,
  ...
)

Arguments

client	Influx_client object created with influxr_connection
database	character string. Database name.
measurement	character string. InfluxDb measurement name.
fields	character vector, NULL or "*". Fields to be selected eg. c('T','Humidity', 'w'). NULL or '*' will select all fields.
from	'POSIX' datetime or character in ISO8601 format which will be parsed to date time eg. '2017-12-31 14:00:00' or simply '2017' for the start of 2017. if NULL all values will be selected.
to	POSIX datetime or character in ISO8601 format which will be parsed to date time eg. '2017-12-31 14:00:00' or simply '2017' for the start of 2017. if NULL all values will be selected. Note: influxr_select returns data points in the range [from, to[, ie: where time >= from and time < to.
tags	named character vector. Only data points tagged with provided tags will be fetched. eg. c(station = 'Hainich', level = 3, method = 'EC').
group_by	character string. How data points should be grouped when an aggregation function is specified, possible values are 'time(1h)' to aggregate by time, or any other time interval or other field. If NULL no grouping will happen.
fill	character string. How should empty datapoints be filled, default to 'null' other possible options are "linear", "none", "null" or "previous"
limit	numeric. How many data points should the result be limited to. If NULL or Inf everything will be returned. Default to one million data points.
desc	logical, not emplemented yet.
extra_conditions	Pass extra conditions to the query.
...	passed to ‘influxr_query'. e.g. 'write_to_file = ’~/test.csv''
aggreagation	character string. Aggregation function to be used. Currently supported functions are 'MEAN','COUNT','DISTINCT', 'INTEGRAL','MEDIAN','MODE', 'SPREAD','STDDEV','SUM', 'FIRST','LAST', 'MIN', 'MAX' if NULL no aggregation is performed.

Details

other options that can be passed to the function are ignore_names and ignore_tags.

Examples

# Read data from InfluxDB instance and store the result in timed rotating 

## Not run: 

influxr_select(
  influxdb_connection,
  database,
  measurement = 'cpu',
  tags = c(level = 1, station = 'work'),
  verbose = TRUE,
  from = '2017-07-10 12:00:00',
  to = '2017-08-10 12:00:00',
  write_handler = save_timed_rotating_files,
  path = my_path,
  base_file_name = 'cpu_',
  rotation_interval = '1 week',
  trunc_start = TRUE
)

## End(Not run)

influxr/influxr documentation built on Aug. 5, 2020, 9:03 p.m.