resolved merge conflicts with master branch

assets/styles/layouts/article/_code.scss

@@ -56,7 +56,7 @@ pre {
     padding: 0;
     font-size: .95rem;
     line-height: 1.5rem;
-    white-space: pre-wrap;
+    white-space: pre;
   }
 }
 

content/v2.0/reference/flux/functions/built-in/outputs/to.md

@@ -35,7 +35,9 @@ to(
 ```
 
 {{% note %}}
+
 ### Output data requirements
+
 The `to()` function converts output data into line protocol and writes it to InfluxDB.
 Line protocol requires each record to have a timestamp, a measurement, a field, and a value.
 All output data must include the following columns:
@@ -47,21 +49,25 @@ All output data must include the following columns:
 {{% /note %}}
 
 ## Parameters
+
 {{% note %}}
 `bucket` OR `bucketID` is **required**.
 {{% /note %}}
 
 ### bucket
+
 The bucket to which data is written. Mutually exclusive with `bucketID`.
 
 _**Data type:** String_
 
 ### bucketID
+
 The ID of the bucket to which data is written. Mutually exclusive with `bucket`.
 
 _**Data type:** String_
 
 ### org
+
 The organization name of the specified [`bucket`](#bucket).
 Only required when writing to a remote host.
 Mutually exclusive with `orgID`
@@ -73,6 +79,7 @@ Specify either an `org` or an `orgID`, but not both.
 {{% /note %}}
 
 ### orgID
+
 The organization ID of the specified [`bucket`](#bucket).
 Only required when writing to a remote host.
 Mutually exclusive with `org`.
@@ -92,18 +99,21 @@ _Required when a `host` is specified._
 _**Data type:** String_ -->
 
 ### timeColumn
+
 The time column of the output.
 Default is `"_time"`.
 
 _**Data type:** String_
 
 ### tagColumns
+
 The tag columns of the output.
 Defaults to all columns with type `string`, excluding all value columns and the `_field` column if present.
 
 _**Data type:** Array of strings_
 
 ### fieldFn
+
 Function that takes a record from the input table and returns an object.
 For each record from the input table, `fieldFn` returns an object that maps output the field key to the output value.
 Default is `(r) => ({ [r._field]: r._value })`
@@ -111,9 +121,14 @@ Default is `(r) => ({ [r._field]: r._value })`
 _**Data type:** Function_
 _**Output data type:** Object_
 
+{{% note %}}
+Make sure `fieldFn` parameter names match each specified parameter. To learn why, see [Match parameter names](/v2.0/reference/flux/language/data-model/#match-parameter-names).
+{{% /note %}}
+
 ## Examples
 
 ### Default to() operation
+
 Given the following table:
 
 | _time | _start | _stop | _measurement | _field | _value |
@@ -138,6 +153,7 @@ _measurement=a temp=99.9 0007
 ```
 
 ### Custom to() operation
+
 The `to()` functions default operation can be overridden. For example, given the following table:
 
 | _time | _start | _stop | tag1 | tag2 | hum  | temp  |
@@ -164,4 +180,5 @@ _tag1=a hum=55.5,temp=99.9 0007
 <hr style="margin-top:4rem"/>
 
 ##### Related InfluxQL functions and statements:
+
 [SELECT INTO](https://docs.influxdata.com/influxdb/latest/query_language/data_exploration/#the-into-clause)

content/v2.0/reference/flux/functions/built-in/transformations/aggregates/aggregatewindow.md

@@ -32,12 +32,18 @@ View the [function definition](#function-definition).
 
 ## Parameters
 
+{{% note %}}
+Make sure `fn` parameter names match each specified parameter. To learn why, see [Match parameter names](/v2.0/reference/flux/language/data-model/#match-parameter-names).
+{{% /note %}}
+
 ### every
+
 The duration of windows.
 
 _**Data type:** Duration_
 
 ### fn
+
 The [aggregate function](/v2.0/reference/flux/functions/built-in/transformations/aggregates) used in the operation.
 
 _**Data type:** Function_
@@ -47,24 +53,28 @@ Only aggregate and selector functions with a `column` parameter (singular) work
 {{% /note %}}
 
 ### column
+
 The column on which to operate.
 Defaults to `"_value"`.
 
 _**Data type:** String_
 
 ### timeSrc
+
 The time column from which time is copied for the aggregate record.
 Defaults to `"_stop"`.
 
 _**Data type:** String_
 
 ### timeDst
+
 The "time destination" column to which time is copied for the aggregate record.
 Defaults to `"_time"`.
 
 _**Data type:** String_
 
 ### createEmpty
+
 For windows without data, this will create an empty window and fill
 it with a `null` aggregate value.
 Defaults to `true`.
@@ -74,6 +84,7 @@ _**Data type:** Boolean_
 ## Examples
 
 ###### Using an aggregate function with default parameters
+
 ```js
 from(bucket: "example-bucket")
   |> range(start: 1h)
@@ -104,6 +115,7 @@ from(bucket: "example-bucket")
 ```
 
 ## Function definition
+
 ```js
 aggregateWindow = (every, fn, column="_value", timeSrc="_stop", timeDst="_time", tables=<-) =>
 	tables
@@ -116,5 +128,6 @@ aggregateWindow = (every, fn, column="_value", timeSrc="_stop", timeDst="_time",
 <hr style="margin-top:4rem"/>
 
 ##### Related InfluxQL functions and statements:
+
 [InfluxQL aggregate functions](https://docs.influxdata.com/influxdb/latest/query_language/functions/#aggregations)  
 [GROUP BY time()](https://docs.influxdata.com/influxdb/latest/query_language/data_exploration/#the-group-by-clause)  

content/v2.0/reference/flux/functions/built-in/transformations/aggregates/difference.md

@@ -11,7 +11,7 @@ weight: 501
 ---
 
 The `difference()` function computes the difference between subsequent records.  
-The user-specified column of numeric type is subtracted while others are kept intact.
+The user-specified columns of numeric type are subtracted while others are kept intact.
 
 _**Function type:** Aggregate_  
 _**Output data type:** Float_
@@ -19,7 +19,7 @@ _**Output data type:** Float_
 ```js
 difference(
   nonNegative: false,
-  column: "_value",
+  columns: ["_value"],
   keepFirst: false
 )
 ```
@@ -32,11 +32,11 @@ When set to `true`, if a value is less than the previous value, it is assumed th
 
 _**Data type:** Boolean_
 
-### column
-The column to use to compute the difference.
-Defaults to `"_value"`.
+### columns
+The columns to use to compute the difference.
+Defaults to `["_value"]`.
 
-_**Data type:** String_
+_**Data type:** Array of Strings_
 
 ### keepFirst
 Indicates the first row should be kept.

content/v2.0/reference/flux/functions/built-in/transformations/aggregates/reduce.md

@@ -30,6 +30,10 @@ However, if two reduced tables write to the same destination group key, the func
 
 ## Parameters
 
+{{% note %}}
+Make sure `fn` parameter names match each specified parameter. To learn why, see [Match parameter names](/v2.0/reference/flux/language/data-model/#match-parameter-names).
+{{% /note %}}
+
 ### fn
 Function to apply to each record with a reducer object ([`identity`](#identity)).
 

content/v2.0/reference/flux/functions/built-in/transformations/drop.md

@@ -28,13 +28,19 @@ drop(fn: (column) => column =~ /usage*/)
 
 ## Parameters
 
+{{% note %}}
+Make sure `fn` parameter names match each specified parameter. To learn why, see [Match parameter names](/v2.0/reference/flux/language/data-model/#match-parameter-names).
+{{% /note %}}
+
 ### columns
+
 Columns to be removed from the table.
 Cannot be used with `fn`.
 
 _**Data type:** Array of strings_
 
 ### fn
+
 A predicate function which takes a column name as a parameter (`column`) and returns
 a boolean indicating whether or not the column should be removed from the table.
 Cannot be used with `columns`.
@@ -44,6 +50,7 @@ _**Data type:** Function_
 ## Examples
 
 ##### Drop a list of columns
+
 ```js
 from(bucket: "example-bucket")
 	|> range(start: -5m)
@@ -51,6 +58,7 @@ from(bucket: "example-bucket")
 ```
 
 ##### Drop columns matching a predicate
+
 ```js
 from(bucket: "example-bucket")
   |> range(start: -5m)
@@ -60,4 +68,5 @@ from(bucket: "example-bucket")
 <hr style="margin-top:4rem"/>
 
 ##### Related InfluxQL functions and statements:
+
 [DROP MEASUREMENT](https://docs.influxdata.com/influxdb/latest/query_language/database_management/#delete-measurements-with-drop-measurement)

content/v2.0/reference/flux/functions/built-in/transformations/filter.md

@@ -22,7 +22,12 @@ filter(fn: (r) => r._measurement == "cpu")
 
 ## Parameters
 
+{{% note %}}
+Make sure `fn` parameter names match each specified parameter. To learn why, see [Match parameter names](/v2.0/reference/flux/language/data-model/#match-parameter-names).
+{{% /note %}}
+
 ### fn
+
 A single argument predicate function that evaluates true or false.
 Records are passed to the function.
 Those that evaluate to true are included in the output tables.
@@ -35,6 +40,7 @@ Objects evaluated in `fn` functions are represented by `r`, short for "record" o
 {{% /note %}}
 
 ## Examples
+
 ```js
 from(bucket:"example-bucket")
   |> range(start:-1h)
@@ -48,4 +54,5 @@ from(bucket:"example-bucket")
 <hr style="margin-top:4rem"/>
 
 ##### Related InfluxQL functions and statements:
+
 [SELECT](https://docs.influxdata.com/influxdb/latest/query_language/data_exploration/#the-basic-select-statement)

content/v2.0/reference/flux/functions/built-in/transformations/keep.md

@@ -27,13 +27,19 @@ keep(fn: (column) => column =~ /inodes*/)
 
 ## Parameters
 
+{{% note %}}
+Make sure `fn` parameter names match each specified parameter. To learn why, see [Match parameter names](/v2.0/reference/flux/language/data-model/#match-parameter-names).
+{{% /note %}}
+
 ### columns
+
 Columns that should be included in the resulting table.
 Cannot be used with `fn`.
 
 _**Data type:** Array of strings_
 
 ### fn
+
 A predicate function which takes a column name as a parameter (`column`) and returns
 a boolean indicating whether or not the column should be included in the resulting table.
 Cannot be used with `columns`.
@@ -43,6 +49,7 @@ _**Data type:** Function_
 ## Examples
 
 ##### Keep a list of columns
+
 ```js
 from(bucket: "example-bucket")
     |> range(start: -5m)
@@ -50,6 +57,7 @@ from(bucket: "example-bucket")
 ```
 
 ##### Keep all columns matching a predicate
+
 ```js
 from(bucket: "example-bucket")
     |> range(start: -5m)

content/v2.0/reference/flux/functions/built-in/transformations/keyvalues.md

@@ -31,6 +31,7 @@ keyValues(fn: (schema) => schema.columns |> filter(fn: (r) =>  r.label =~ /usage
 {{% /note %}}
 
 ### keyColumns
+
 A list of columns from which values are extracted.
 All columns indicated must be of the same type.
 Each input table must have all of the columns listed by the `keyColumns` parameter.
@@ -38,9 +39,14 @@ Each input table must have all of the columns listed by the `keyColumns` paramet
 _**Data type:** Array of strings_
 
 ### fn
+
 Function used to identify a set of columns.
 All columns indicated must be of the same type.
 
+{{% note %}}
+Make sure `fn` parameter names match each specified parameter. To learn why, see [Match parameter names](/v2.0/reference/flux/language/data-model/#match-parameter-names).
+{{% /note %}}
+
 _**Data type:** Function_
 
 ## Additional requirements
@@ -52,6 +58,7 @@ _**Data type:** Function_
 ## Examples
 
 ##### Get key values from explicitly defined columns
+
 ```js
 from(bucket: "example-bucket")
   |> range(start: -30m)
@@ -60,6 +67,7 @@ from(bucket: "example-bucket")
 ```
 
 ##### Get key values from columns matching a regular expression
+
 ```js
 from(bucket: "example-bucket")
   |> range(start: -30m)
@@ -70,6 +78,7 @@ from(bucket: "example-bucket")
 <hr style="margin-top:4rem"/>
 
 ##### Related InfluxQL functions and statements:
+
 [SHOW MEASUREMENTS](https://docs.influxdata.com/influxdb/latest/query_language/schema_exploration/#show-measurements)  
 [SHOW FIELD KEYS](https://docs.influxdata.com/influxdb/latest/query_language/schema_exploration/#show-field-keys)  
 [SHOW TAG KEYS](https://docs.influxdata.com/influxdb/latest/query_language/schema_exploration/#show-tag-keys)  

content/v2.0/reference/flux/functions/built-in/transformations/map.md

@@ -26,7 +26,12 @@ map(fn: (r) => ({ _value: r._value * r._value }))
 
 ## Parameters
 
+{{% note %}}
+Make sure `fn` parameter names match each specified parameter. To learn why, see [Match parameter names](/v2.0/reference/flux/language/data-model/#match-parameter-names).
+{{% /note %}}
+
 ### fn
+
 A single argument function that to apply to each record.
 The return value must be an object.
 
@@ -39,6 +44,7 @@ Objects evaluated in `fn` functions are represented by `r`, short for "record" o
 ## Important notes
 
 #### Preserve columns
+
 By default, `map()` drops any columns that:
 
 1. Are not part of the input table's group key.
@@ -58,6 +64,7 @@ map(fn: (r) => ({ r with newColumn: r._value * 2 }))
 ## Examples
 
 ###### Square the value of each record
+
 ```js
 from(bucket:"example-bucket")
   |> filter(fn: (r) =>
@@ -70,6 +77,7 @@ from(bucket:"example-bucket")
 ```
 
 ###### Create a new table with new format
+
 ```js
 from(bucket:"example-bucket")
     |> filter(fn: (r) =>

content/v2.0/reference/flux/functions/built-in/transformations/rename.md

@@ -30,13 +30,19 @@ rename(fn: (column) => "{column}_new")
 
 ## Parameters
 
+{{% note %}}
+Make sure `fn` parameter names match each specified parameter. To learn why, see [Match parameter names](/v2.0/reference/flux/language/data-model/#match-parameter-names).
+{{% /note %}}
+
 ### columns
+
 A map of columns to rename and their corresponding new names.
 Cannot be used with `fn`.
 
 _**Data type:** Object_
 
 ### fn
+
 A function mapping between old and new column names.
 Cannot be used with `columns`.
 
@@ -45,6 +51,7 @@ _**Data type:** Function_
 ## Examples
 
 ##### Rename a single column
+
 ```js
 from(bucket: "example-bucket")
     |> range(start: -5m)
@@ -52,6 +59,7 @@ from(bucket: "example-bucket")
 ```
 
 ##### Rename all columns using a function
+
 ```js
 from(bucket: "example-bucket")
     |> range(start: -5m)

content/v2.0/reference/flux/functions/built-in/transformations/statecount.md

@@ -28,7 +28,12 @@ and does not affect the state count._
 
 ## Parameters
 
+{{% note %}}
+Make sure `fn` parameter names match each specified parameter. To learn why, see [Match parameter names](/v2.0/reference/flux/language/data-model/#match-parameter-names).
+{{% /note %}}
+
 ### fn
+
 A single argument function that evaluates true or false to identify the state of the record.
 Records are passed to the function.
 Those that evaluate to `true` increment the state count.
@@ -37,11 +42,13 @@ Those that evaluate to `false` reset the state count.
 _**Data type:** Function_
 
 ### column
+
 The name of the column added to each record that contains the incremented state count.
 
 _**Data type:** String_
 
 ## Examples
+
 ```js
 from("monitor/autogen")
   |> range(start: -1h)

content/v2.0/reference/flux/functions/built-in/transformations/stateduration.md

@@ -34,7 +34,12 @@ and does not affect the state duration._
 
 ## Parameters
 
+{{% note %}}
+Make sure `fn` parameter names match each specified parameter. To learn why, see [Match parameter names](/v2.0/reference/flux/language/data-model/#match-parameter-names).
+{{% /note %}}
+
 ### fn
+
 A single argument function that evaluates true or false to identify the state of the record.
 Records are passed to the function.
 Those that evaluate to `true` increment the state duration.
@@ -43,17 +48,20 @@ Those that evaluate to `false` reset the state duration.
 _**Data type:** Function_
 
 ### column
+
 The name of the column added to each record that contains the state duration.
 
 _**Data type:** String_
 
 ### unit
+
 The unit of time in which the state duration is incremented.
 For example: `1s`, `1m`, `1h`, etc.
 
 _**Data type:** Duration_
 
 ## Examples
+
 ```js
 from("monitor/autogen")
   |> range(start: -1h)

content/v2.0/reference/flux/functions/built-in/transformations/stream-table/tablefind.md

@@ -21,7 +21,12 @@ tableFind(column: "_value")
 
 ## Parameters
 
+{{% note %}}
+Make sure `fn` parameter names match each specified parameter. To learn why, see [Match parameter names](/v2.0/reference/flux/language/data-model/#match-parameter-names).
+{{% /note %}}
+
 ### fn
+
 A predicate function for matching keys in a table's group key.
 `tableFind` returns the first table that resolves as `true`.
 It expects a `key` argument which represents a group key in the input stream.
@@ -29,11 +34,13 @@ It expects a `key` argument which represents a group key in the input stream.
 _**Data type:** Function_
 
 ##### Example fn function
+
 ```js
 (key) => key._field == "fieldName"
 ```
 
 ## Example
+
 ```js
 t = from(bucket:"example-bucket")
     |> range(start: -5m)

content/v2.0/reference/flux/language/data-model.md

@@ -18,9 +18,11 @@ Flux employs a basic data model built from basic data types.
 The data model consists of tables, records, columns and streams.
 
 ## Record
+
 A **record** is a tuple of named values and is represented using an object type.
 
 ## Column
+
 A **column** has a label and a data type.
 The available data types for a column are:
 
@@ -36,6 +38,7 @@ The available data types for a column are:
 | duration  | A nanosecond precision duration of time.  |
 
 ## Table
+
 A **table** is set of records with a common set of columns and a group key.
 
 The group key is a list of columns.
@@ -50,6 +53,7 @@ A tables schema consists of its group key and its columns' labels and types.
 {{% /note %}}
 
 ## Stream of tables
+
 A **stream** represents a potentially unbounded set of tables.
 A stream is grouped into individual tables using their respective group keys.
 Tables within a stream each have a unique group key value.
@@ -60,6 +64,7 @@ types that make up stream and table types
 {{% /note %}}
 
 ## Missing values (null)
+
 `null` is a predeclared identifier representing a missing or unknown value.
 `null` is the only value comprising the _null type_.
 Any non-boolean operator that operates on basic types returns _null_ when at least one of its operands is _null_.
@@ -101,6 +106,7 @@ In order to perform such a check, Flux provides a built-in `exists` operator:
 {{% /note %}}
 
 ## Transformations
+
 Transformations define a change to a stream.
 Transformations may consume an input stream and always produce a new output stream.
 The output stream group keys have a stable output order based on the input stream.
@@ -111,3 +117,25 @@ Transformations that modify group keys or values regroup the tables in the outpu
 A transformation produces side effects when constructed from a function that produces side effects.
 
 Transformations are represented using function types.
+
+### Match parameter names
+
+Some transformations (for example, `map` and `filter`) are represented using higher-order functions (functions that accept other functions).
+Each argument passed into a function must match the parameter name defined for the function.
+
+For example, `filter` accepts `fn`, which takes one argument named `r`:
+
+ ```js
+from(bucket: "db")
+    |> filter(fn: (r) => ...)
+```
+
+ If a parameter is renamed from `r` to `v`, the script fails:
+ 
+```js
+from(bucket: "db")
+    |> filter(fn: (v) => ...)
+ // FAILS!: 'v' != 'r'.
+```
+
+Because Flux does not support positional arguments, parameter names matter. The transformation (in this case, `filter`) must know `r` is the parameter name to successfully invoke the function.

content/v2.0/reference/flux/language/expressions.md

@@ -22,6 +22,7 @@ PrimaryExpression = identifier | Literal | "(" Expression ")" .
 ```
 
 ## Literals
+
 Literals construct a value.
 
 ```js
@@ -37,6 +38,7 @@ Literal = int_lit
 ```
 
 ### Object literals
+
 Object literals construct a value with the object type.
 
 ```js
@@ -121,6 +123,23 @@ f(a:1, b:9.6)
 float(v:1)
 ```
 
+Use short notation in a call expression when the name of every argument matches the name of every parameter.
+
+##### Examples of short notation in call expressions
+
+```js
+add(a: a, b: b) //long notation
+add(a, b) // short notation equivalent
+
+add = (a,b) => a + b
+a = 1
+b = 2
+
+// Don't mix short and long notation.
+add(a: a, b)
+add(a, b: b)
+```
+
 ## Pipe expressions
 
 A _pipe expression_ is a call expression with an implicit piped argument.

content/v2.0/reference/release-notes/influxdb-cloud.md

@@ -10,6 +10,18 @@ aliases:
   - /cloud/about/release-notes
 ---
 
+## 2019-07-23 _General Availability_
+
+### Features
+
+- **InfluxDB 2.0 alpha-15** –
+_See the [alpha-9 release notes](/v2.0/reference/release-notes/influxdb/#v2-0-0-alpha-15-2019-07-11) for details._
+- Pay As You Go Pricing Plan.
+- Adjusted Free Plan rate limits.
+- Timezone selection in the user interface.
+
+---
+
 ## 2019-05-06 _Public Beta_
 
 ### Features

content/v2.0/visualize-data/variables/_index.md

@@ -59,8 +59,9 @@ This variable is typically used to define the `every` or `period` parameters of
 [`window()` function](/v2.0/reference/flux/functions/built-in/transformations/window)
 in data aggregation operations.
 
-The value of this variable is calculated by dividing the total time within the displayed
-time range by the dashboard refresh interval (defined by the **Refresh** dropdown).
+The value of this variable is calculated by analyzing the duration of the Flux
+query it is used within. Queries that fetch data from a longer time range will
+have a larger `v.windowPeriod` duration.
 
 ## Custom dashboard variables
 Create, manage, and use custom dashboard variables in the InfluxDB user interface (UI).

data/telegraf_plugins.yml

@@ -416,7 +416,7 @@ input:
   - name: Filecount
     id: filecount
     description: |
-      The Filecount input plugin counts files in directories that match certain criteria.
+      The Filecount input plugin reports the number and total size of files in directories that match certain criteria.
     link: https://github.com/influxdata/telegraf/blob/release-1.11/plugins/inputs/filecount/README.md
     introduced: 1.8.0
     tags: [linux, macos, windows, systems]