From 8541187af12ff991ab34393a336838f3898bc3d6 Mon Sep 17 00:00:00 2001 From: Jason Stirnaman Date: Tue, 15 Apr 2025 14:43:44 -0500 Subject: [PATCH] chore(influxdb3): Clustered: use shared glossary file --- .../influxdb3/clustered/reference/glossary.md | 1145 +---------------- 1 file changed, 4 insertions(+), 1141 deletions(-) diff --git a/content/influxdb3/clustered/reference/glossary.md b/content/influxdb3/clustered/reference/glossary.md index dc9cf47ea..02f491449 100644 --- a/content/influxdb3/clustered/reference/glossary.md +++ b/content/influxdb3/clustered/reference/glossary.md @@ -7,1146 +7,9 @@ menu: influxdb3_clustered: parent: Reference influxdb3/clustered/tags: [glossary] +source: /shared/influxdb3-reference/glossary.md --- -[A](#a) | [B](#b) | [C](#c) | [D](#d) | [E](#e) | [F](#f) | [G](#g) | [H](#h) | [I](#i) | [J](#j) | [K](#k) | [L](#l) | [M](#m) | [N](#n) | [O](#o) | [P](#p) | [Q](#q) | [R](#r) | [S](#s) | [T](#t) | [U](#u) | [V](#v) | [W](#w) | X | Y | Z - -## A - -### abstract syntax tree (AST) - -Tree representation of source code that shows the structure, content, and rules -of programming statements and discards additional syntax elements. -The tree is hierarchical, with elements of program statements broken down into their parts. - -For more information about AST design, see [Abstract Syntax Tree on Wikipedia](https://en.wikipedia.org/wiki/Abstract_syntax_tree). - -### agent - -A background process started by (or on behalf of) a user that typically requires user input. - -[Telegraf](/telegraf/v1/) is an agent that requires user input -(a configuration file) to gather metrics from declared input plugins and sends -metrics to declared output plugins, based on the plugins enabled for a configuration. - -Related entries: -[input plugin](#input-plugin), -[output plugin](#output-plugin), -[daemon](#daemon) - -### aggregator plugin - -Receives metrics from input plugins, creates aggregate metrics, and then passes aggregate metrics to configured output plugins. - -Related entries: -[input plugin](#input-plugin), -[output plugin](#output-plugin), -[processor plugin](#processor-plugin) - -### aggregate - -A function that returns an aggregated value across a set of points. -For a list of available aggregation functions, -see [SQL aggregate functions](/influxdb3/clustered/reference/sql/functions/aggregate/). - - - -Related entries: -[function](#function), -[selector](#selector) - -### API - -Application programming interface that facilitates and standardizes communication -between two or more computer programs. - -### argument - -A value passed to a function or command that determines how the process operates. - -Related entries: -[parameter](#parameter) - -## B - -### batch - -A collection of points in line protocol format, separated by newlines (`0x0A`). -Submitting a batch of points using a single HTTP request to the write endpoints -drastically increases performance by reducing the HTTP overhead. -InfluxData typically recommends batch sizes of 5,000-10,000 points. -In some use cases, performance may improve with significantly smaller or larger batches. - -Related entries: -[line protocol](#line-protocol-lp), -[point](#point) - -### batch size - -The number of lines or individual data points in a line protocol batch. -The Telegraf agent sends metrics to output plugins in batches rather than individually. -Batch size controls the size of each write batch that Telegraf sends to the output plugins. - -Related entries: -[output plugin](#output-plugin) - -### bin - -In a cumulative histogram, a bin includes all data points less than or equal to a specified upper bound. -In a normal histogram, a bin includes all data points between the upper and lower bounds. -Histogram bins are also sometimes referred to as "buckets." - -### boolean - -A data type with two possible values: true or false. -By convention, you can express `true` as the integer `1` and false as the integer `0` (zero). - -### bucket - -"Bucket" is the term used in InfluxDB 2.x and _InfluxDB Cloud Serverless_ to refer -to a named location where time series data is stored. -Bucket is synonymous with "database" when using InfluxDB Clustered. - -Related entries: -[database](#database) - -## C - -### CSV - -Comma-separated values (CSV) delimits text between commas to separate values. -A CSV file stores tabular data (numbers and text) in plain text. -Each line of the file is a data row. -Each row consists of one or more columns, separated by commas. -CSV file format is not fully standardized. - -### cardinality - -Cardinality is the number of unique values in a set. -Series cardinality is the number of unique [series](#series) in a database as a whole. -With the InfluxDB 3 storage engine, high series cardinality _does not_ affect performance. - -### cluster - -A collection of servers or processes that work together as a single unit. -An InfluxDB cluster is a collection of InfluxDB servers dedicated -to the workload of a single customer. - -### collect - -Collect and write time series data to InfluxDB using line protocol and any of the following tools: - -- Telegraf -- the InfluxDB v1 or v2 HTTP APIs -- v1 or v2 `influx` command line interface (CLI) -- InfluxDB client libraries - -### collection interval - -The default global interval for collecting data from each Telegraf input plugin. -The collection interval can be overridden by each individual input plugin's configuration. - -Related entries: -[input plugin](#input-plugin) - -### collection jitter - -Collection jitter prevents every input plugin from collecting metrics simultaneously, -which can have a measurable effect on the system. -For each collection interval, every Telegraf input plugin sleeps for a random -time between zero and the collection jitter before collecting the metrics. - -Related entries: -[collection interval](#collection-interval), -[input plugin](#input-plugin) - -### column - -InfluxDB data is stored in tables within rows and columns. -Columns store tag sets and fields sets, and time values. -The only required column is _time_, which stores timestamps and is included -in all InfluxDB tables. - -### common log format (CLF) - -A standardized text file format used by the InfluxDB server to create log -entries when generating server log files. - -### compaction - -Compressing time series data to optimize disk usage. - -### continuous query (CQ) - -Continuous queries are a feature of InfluxDB 1.x used to regularly downsample -or process time series data. - -## D - -### daemon - -A background process that runs without user input. - -### dashboard - -A collection of data visualizations used to query and display time series data. -There a many tools designed specifically to create dashboards including -[Grafana](https://grafana.com), [Apache Superset](https://superset.apache.org/), -[Tableau](https://www.tableau.com/), and others. - - - -### data model - -A data model organizes elements of data and standardizes how they relate to one -another and to properties of the real world entities. - -For information about the InfluxDB data model, see -[InfluxDB data organization](/influxdb3/clustered/get-started/#data-organization) - -### data service - -Stores time series data and handles writes and queries. - -### data source - -A source of data that InfluxDB collects or queries data from. - -Related entries: -[database](#database) - -### data type - -A data type is defined by the values it can take, the programming language used, -or the operations that can be performed on it. - -InfluxDB supports the following data types: - -- string -- boolean -- float (64-bit) -- integer (64-bit) -- unsigned integer (64-bit) -- time - -For more information about different data types, see: - -- [line protocol](/influxdb/v2/reference/syntax/line-protocol/#data-types-and-format) -- [InfluxQL](/influxdb/v1/query_language/spec/#literals) -- [InfluxDB](/influxdb/v2/reference/syntax/line-protocol/#data-types-and-format) - -#### database - -A named location where time series data is stored. - -In InfluxDB 1.x, a database represented a logical container for users, retention -policies, continuous queries, and time series data. -In InfluxDB 2.x, the equivalent of this concept is an InfluxDB [bucket](#bucket). - -Related entries: -[bucket](#bucket), -[retention policy](#retention-policy-rp) - -### date-time - -InfluxDB stores the date-time format for each data point in a timestamp with -nanosecond-precision Unix time. -Specifying a timestamp is optional. -If a timestamp isn't specified for a data point, InfluxDB uses the server’s -local nanosecond timestamp in UTC. - -### downsample - -Aggregating high resolution data into lower resolution data to preserve disk space. - -### duration - -A data type that represents a duration of time--for example, `1s`, `1m`, `1h`, `1d`. -Retention periods are set using durations. - -Related entries: -[retention period](#retention-period) - -## E - -### event - -Metrics gathered at irregular time intervals. - -### expression - -A combination of one or more constants, variables, operators, and functions. - -In the following SQL example, `now() - INTERVAL '7 days'` is an expression that calculates the difference between the `now()` function expression and the duration represented by `INTERVAL '7 days`: - -```sql -SELECT * -FROM home -WHERE - time >= now() - INTERVAL '7 days' -``` - -## F - -### field - -A key-value pair in InfluxDB's data structure that records a data value. -Generally, field values change over time. -Fields are required in InfluxDB's data structure. - -Related entries: -[field key](#field-key), -[field set](#field-set), -[field value](#field-value), -[tag](#tag) - -### field key - -The key of the key-value pair. -Field keys are strings. - -Related entries: -[field](#field), -[field set](#field-set), -[field value](#field-value), -[tag key](#tag-key) - -### field set - -The collection of field key-value pairs. - -Related entries: -[field](#field), -[field key](#field-key), -[field value](#field-value), -[point](#point) - -### field value - -The value of a key-value pair. -Field values are the actual data; they can be strings, floats, integers, unsigned integers or booleans. -A field value is always associated with a timestamp. - -Related entries: -[field](#field), -[field key](#field-key), -[field set](#field-set), -[tag set](#tag-set), -[tag value](#tag-value), -[timestamp](#timestamp) - -### file block - -A file block is a fixed-length chunk of data read into memory when requested by an application. - -### float - -A real number written with a decimal point dividing the integer and fractional parts (`1.0`, `3.14`, `-20.1`). -InfluxDB supports 64-bit float values. - -### flush interval - -The global interval for flushing data from each Telegraf output plugin to its destination. -This value should not be set lower than the collection interval. - -Related entries: -[collection interval](#collection-interval), -[flush jitter](#flush-jitter), -[output plugin](#output-plugin) - -### flush jitter - -Flush jitter prevents every Telegraf output plugin from sending writes -simultaneously, which can overwhelm some data sinks. -Each flush interval, every Telegraf output plugin sleeps for a random time -between zero and the flush jitter before emitting metrics. -Flush jitter smooths out write spikes when running a large number of Telegraf instances. - -Related entries: -[flush interval](#flush-interval), -[output plugin](#output-plugin) - -### function - -A function is an operation that performs a specific task. -Functions take input, operate on that input, and then return output. -For a complete list of available SQL functions, see -[SQL functions](/influxdb3/clustered/reference/sql/functions/). - - - -Related entries: -[aggregate](#aggregate), -[selector](#selector) - -## G - -### gzip - -gzip is a type of data compression that compress chunks of data, which is -restored by unzipping compressed gzip files. -The gzip file extension is `.gz`. - -## H - -### histogram - -A visual representation of statistical information that uses rectangles to show -the frequency of data items in successive, equal intervals or bins. - -## I - -### identifier - -Identifiers are tokens that refer to specific database objects such as database -names, field keys, measurement names, tag keys, etc. - -Related entries: -[database](#database), -[field key](#field-key), -[measurement](#measurement), -[tag key](#tag-key) - -### influx - -`influx` is a command line interface (CLI) that interacts with the InfluxDB v1.x and v2.x server. - -### influxctl - -[`influxctl`](/influxdb3/clustered/reference/cli/influxctl/) is a CLI that -performs [administrative tasks](/influxdb3/clustered/admin/) for an -InfluxDB cluster. - -### influxd - -`influxd` is the InfluxDB OSS v1.x and v2.x daemon that runs the InfluxDB server -and other required processes. - -### InfluxDB - -An open source time series database (TSDB) developed by InfluxData, optimized -for fast, high-availability storage and retrieval of -time series data in fields such as operations monitoring, application metrics, -Internet of Things sensor data, and real-time analytics. - -### InfluxQL - -The SQL-like query language used to query data in InfluxDB. - -### input plugin - -Telegraf input plugins actively gather metrics and deliver them to the core agent, -where aggregator, processor, and output plugins can operate on the metrics. -To activate an input plugin, enable and configure it in the -Telegraf configuration file. - -Related entries: -[aggregator plugin](#aggregator-plugin), -[collection interval](#collection-interval), -[output plugin](#output-plugin), -[processor plugin](#processor-plugin) - -### instance - -An entity comprising data on a server (or virtual server in cloud computing). - - -### integer - -A whole number that is positive, negative, or zero (`0`, `-5`, `143`). -InfluxDB supports 64-bit integers (minimum: `-9223372036854775808`, maximum: `9223372036854775807`). - -Related entries: -[unsigned integer](#unsigned-integer) - -### IOx - -The IOx (InfluxDB 3) storage engine is a real-time, columnar database optimized for time series -data built in Rust on top of [Apache Arrow](https://arrow.apache.org/) and -[DataFusion](https://arrow.apache.org/datafusion/user-guide/introduction.html). -IOx replaces the [TSM (Time Structured Merge tree)](#tsm-time-structured-merge-tree) storage engine. - -## J - -### JWT - -Typically, JSON web tokens (JWT) are used to authenticate users between an -identity provider and a service provider. -A server can generate a JWT to assert any business processes. -For example, an "admin" token sent to a client can prove the client is logged in as admin. -Tokens are signed by one party's private key (typically, the server). -Private keys are used by both parties to verify that a token is legitimate. - -JWT uses an open standard specified in [RFC 7519](https://tools.ietf.org/html/rfc7519). - -### Jaeger - -Open source tracing used in distributed systems to monitor and troubleshoot transactions. - -### JSON - -JavaScript Object Notation (JSON) is an open-standard file format that uses -human-readable text to transmit data objects consisting of attribute–value pairs -and array data types. - -## K - -### keyword - -A keyword is reserved by a program because it has special meaning. -Every programming language has a set of keywords (reserved names) that cannot be used as identifiers--for example, -you can't use `SELECT` (an SQL keyword) as a variable name in an SQL query. - -See keyword lists: - -- [SQL keywords](/influxdb3/clustered/reference/sql/#keywords) -- [InfluxQL keywords](/influxdb3/clustered/reference/influxql/#keywords) - -## L - -### literal - -A literal is value in an expression, a number, character, string, function, record, or array. -Literal values are interpreted as defined. - -### load balancing - -Improves workload distribution across multiple computing resources in a network. -Load balancing optimizes resource use, maximizes throughput, minimizes response -time, and avoids overloading a single resource. -Using multiple components with load balancing instead of a single component may -increase reliability and availability. -If requests to any server in a network increase, requests are forwarded to -another server with more capacity. -Load balancing can also refer to the communications channels themselves. - -### logs - -Logs record information. -Event logs describe system events and activity that help to describe and diagnose problems. -Transaction logs describe changes to stored data that help recover data if a -database crashes or other errors occur. - -### line protocol (LP) - -The text based format for writing points to InfluxDB. -See [line protocol](/influxdb3/clustered/reference/syntax/line-protocol/). - -## M - -### measurement - -The part of InfluxDB's data structure that describes the data stored in associated fields. -Measurements are strings. - -Related entries: -[field](#field), [series](#series) - -### metric - -Data tracked over time. - -### metric buffer - -The metric buffer caches individual metrics when writes are failing for an Telegraf output plugin. -Telegraf will attempt to flush the buffer upon a successful write to the output. -The oldest metrics are dropped first when this buffer fills. - -Related entries: -[output plugin](#output-plugin) - -### missing values - -Denoted by a null value. -Identifies missing information, which may be useful to include in an error message. - -## N - -### node - -An independent process or server in a cluster. - -Related entries: -[cluster](#cluster), -[server](#server) - -### now - -The local server's nanosecond timestamp. - -### null - -A data type that represents a missing or unknown value. -Denoted by the `null` value. -Values of [tags](#tag) and [fields](#field) may be `null`, but timestamp values are never `null`. - -## O - -### operator - -A symbol that usually represents an action or process. -For example: `+`, `-`, `>`. - -Related entries: -[operand](#operand) - -### operand - -The object or value on either side of an [operator](#operator). - -Related entries: -[operator](#operator) - -### organization - -An InfluxDB v2 concept that describes workspace for a group of users. -All InfluxDB v2 dashboards, tasks, buckets, members, and so on, belong to an organization. -Organizations are not part of InfluxDB Clustered. - -### owner - -A type of role for a user. -Owners have read/write permissions. -Users can have owner roles for databases and other resources. - -Role permissions are separate from API token permissions. For additional -information on API tokens, see [token](#token). - -### output plugin - -Telegraf output plugins deliver metrics to their configured destination. -To activate an output plugin, enable and configure the plugin in Telegraf's configuration file. - -Related entries: -[aggregator plugin](#aggregator-plugin), -[flush interval](#flush-interval), -[input plugin](#input-plugin), -[processor plugin](#processor-plugin) - -## P - -### parameter - -A key-value pair used to pass information to a function that determines how the -function operates. - -Related entries: -[argument](#argument) - -### pipe - -Method for passing information from one process to another. -For example, an output parameter from one process is input to another process. -Information passed through a pipe is retained until the receiving process reads the information. - -### point - -Single data record identified by its _measurement_, _tag keys_, _tag values_, -_field key_, and _timestamp_. - -In a [series](#series), each point has a unique timestamp. -If you write a point to a series with a timestamp that matches an existing point, -the field set becomes a union of the old and new field set, where any ties go to -the new field set. - -Related entries: -[measurement](#measurement), -[tag set](#tag-set), -[field set](#field-set), -[timestamp](#timestamp) - -### primary key - -With the InfluxDB 3 storage engine, the primary key is the list of columns -used to uniquely identify each row in a table. -Rows are uniquely identified by their timestamp and tag set. -A row's primary key tag set does not include tags with null values. - -### precision - -The precision configuration setting determines the timestamp precision retained -for input data points. -All incoming timestamps are truncated to the specified precision. -Valid precisions are `ns`, `us` or `µs`, `ms`, and `s`. - -In Telegraf, truncated timestamps are padded with zeros to create a nanosecond timestamp. -Telegraf output plugins emit timestamps in nanoseconds. -For example, if the precision is set to `ms`, the nanosecond epoch timestamp `1480000000123456789` is truncated to `1480000000123` in millisecond precision and padded with zeroes to make a new, less precise nanosecond timestamp of `1480000000123000000`. -Telegraf output plugins do not alter the timestamp further. -The precision setting is ignored for service input plugins. - -Related entries: -[aggregator plugin](#aggregator-plugin), -[input plugin](#input-plugin), -[output plugin](#output-plugin), -[processor plugin](#processor-plugin), -[service input plugin](#service-input-plugin) - -### predicate expression - -A predicate expression compares two values and returns `true` or `false` based on -the relationship between the two values. -A predicate expression is comprised of a left operand, a comparison operator, and a right operand. - -### process - -A set of predetermined rules. -A process can refer to instructions being executed by the computer processor or -refer to the act of manipulating data. - -### processor plugin - -Telegraf processor plugins transform, decorate, and filter metrics collected by -input plugins, passing the transformed metrics to the output plugins. - -Related entries: -[aggregator plugin](#aggregator-plugin), -[input plugin](#input-plugin), -[output plugin](#output-plugin) - -### Prometheus format - -A simple text-based format for exposing metrics and ingesting them into Prometheus. - -## Q - -### query - -A request for information. -An InfluxDB query returns time series data. - -See [Query data in InfluxDB](/influxdb3/clustered/query-data/). - -### query plan - -A sequence of steps (_nodes_) that the InfluxDB Querier devises and executes to calculate the result of the query in the least amount of time. -A _logical plan_ is a high level representation of a query and doesn't consider cluster configuration or data organization. -A _physical plan_ represents the query execution plan and data flow through plan nodes that read (_scan_), deduplicate, merge, filter, and sort data. -A physical plan is optimized for the cluster configuration and data organization. - -See [Query plans](/influxdb3/clustered/reference/internals/query-plans/). - -## R - -### REPL - -A Read-Eval-Print Loop (REPL) is an interactive programming environment where -you type a command and immediately see the result. - -### regular expressions - -Regular expressions (regex or regexp) are patterns used to match character -combinations in strings. - -### rejected points - -In a batch of data, points that InfluxDB couldn't write to a database. -Field type conflicts are a common cause of rejected points. - -### retention period - -The [duration](#duration) of time that a database retains data. -InfluxDB drops points with timestamps older than their database's retention period -relative to [now](#now). -The minimum retention period is **one hour**. - -Related entries: -[bucket](#bucket) - -### retention policy (RP) - -A retention policy is part of the InfluxDB 1.x data model that describes how long -InfluxDB keeps data (duration), how many copies of the data to store when in a -in the cluster (replication factor), and the time range covered by shard groups -(shard group duration). RPs are unique per database and along with the measurement -and tag set define a series. - -In {{< product-name >}}, the equivalent is [retention period](#retention-period), -however retention periods are not part of the data model. -The retention period describes the data persistence behavior of a database. - -Related entries: -[retention period](#retention-period), - -### RFC3339 timestamp - -A timestamp that uses the human-readable DateTime format proposed in -[RFC 3339](https://tools.ietf.org/html/rfc3339) (for example: `2020-01-01T00:00:00.00Z`). - -Related entries: -[RFC3339Nano timestamp](#rfc3339nano-timestamp), -[timestamp](#timestamp), -[unix timestamp](#unix-timestamp) - -### RFC3339Nano timestamp - -A [Golang representation of the RFC 3339 DateTime format](https://go.dev/src/time/format.go) -that uses nanosecond resolution--for example: -`2006-01-02T15:04:05.999999999Z07:00`. - -InfluxDB clients can return RFC3339Nano timestamps in log events and CSV-formatted -query results. - -Related entries: -[RFC3339 timestamp](#rfc3339-timestamp), -[timestamp](#timestamp), -[unix timestamp](#unix-timestamp) - -### row - -A row in a [table](#table) represents a specific record or instance of data. -[Column](#column) values in a row represent specific attributes or properties of the instance. -Each row has a [primary key](/#primary-key) that makes the row unique from other rows in the table. - -Related entries: -[column](#column), -[primary key](#primary-key), -[series](#series), -[table](#table) - -## S - -### schema - -How data is organized in InfluxDB. -The fundamentals of the InfluxDB schema are databases, measurements, -tag keys, tag values, and field keys. - -Related entries: -[bucket](#bucket), -[field key](#field-key), -[measurement](#measurement), -[series](#series), -[tag key](#tag-key), -[tag value](#tag-value) - -### secret - -Secrets are key-value pairs that contain information you want to control access -to, such as API keys, passwords, or certificates. - -### selector - -A function that returns a single point from the range of specified points. -See [SQL selector functions](/influxdb3/clustered/reference/sql/functions/selector/) -for a complete list of available SQL selector functions. - -Related entries: -[aggregate](#aggregate), -[function](#function), -[transformation](#transformation) - -### series - -In the InfluxDB 3 data structure, a collection of data that share a common -_measurement_ and _tag set_. - -Related entries: -[field set](#field-set), -[measurement](#measurement), -[tag set](#tag-set) - -### series cardinality - -The number of unique measurement (table), tag set, and field key combinations in an InfluxDB database. - -For example, assume that an InfluxDB database has one measurement. -The single measurement has two tag keys: `email` and `status`. -If there are three different `email` tag values, -and each email address is associated with two -different `status` tag values, then the series cardinality for the measurement is 6 -(3 × 2 = 6): - -| email | status | -| :-------------------- | :----- | -| lorr@influxdata.com | start | -| lorr@influxdata.com | finish | -| marv@influxdata.com | start | -| marv@influxdata.com | finish | -| cliff@influxdata.com | start | -| cliff@influxdata.com | finish | - -In some cases, performing this multiplication may overestimate series cardinality -because of the presence of dependent tags. -Dependent tags are scoped by another tag and do not increase series cardinality. -If we add the tag `firstname` to the preceding example, the series cardinality -would not be 18 (3 × 2 × 3 = 18). -The series cardinality would remain unchanged at 6, as `firstname` is already scoped by the `email` tag: - -| email | status | firstname | -| :------------------- | :----- | :-------- | -| lorr@influxdata.com | start | lorraine | -| lorr@influxdata.com | finish | lorraine | -| marv@influxdata.com | start | marvin | -| marv@influxdata.com | finish | marvin | -| cliff@influxdata.com | start | clifford | -| cliff@influxdata.com | finish | clifford | - -Related entries: -[field key](#field-key), -[measurement](#measurement), -[tag key](#tag-key), -[tag set](#tag-set) - -### series key - -A series key identifies a particular series by measurement, tag set, and field key. - -For example: - -```text -# measurement, tag set, field key -h2o_level, location=santa_monica, h2o_feet -``` - -Related entries: -[series](#series) - -### server - -A computer, virtual or physical, running InfluxDB. - - -### service input plugin - -Telegraf input plugins that run in a passive collection mode while the Telegraf agent is running. -Service input plugins listen on a socket for known protocol inputs, or apply -their own logic to ingested metrics before delivering metrics to the Telegraf agent. - -Related entries: -[aggregator plugin](#aggregator-plugin), -[input plugin](#input-plugin), -[output plugin](#output-plugin), -[processor plugin](#processor-plugin) - -### string - -A data type used to represent text. - -## T - -### TCP - -Transmission Control Protocol. - -### table - -A collection of related data organized in a structured way with a predefined set -of columns and data types. -Each row in the table represents a specific record or instance of the data, and -each column represents a specific attribute or property of the data. - -In InfluxDB Clustered, a table represents a measurement. - -Related entries: -[column](#column), -[measurement](#measurement), -[primary key](#primary-key), -[row](#row) - -### tag - -The key-value pair in InfluxDB's data structure that records metadata. -Tags are an optional part of InfluxDB's data structure but they are useful for -storing commonly queried metadata. - -Related entries: -[field](#field), -[tag key](#tag-key), -[tag set](#tag-set), -[tag value](#tag-value) - -### tag key - -The key of a tag key-value pair. -Tag keys are strings and store metadata. - -Related entries: -[field key](#field-key), -[tag](#tag), -[tag set](#tag-set), -[tag value](#tag-value) - -### tag set - -The collection of tag keys and tag values on a point. - -Related entries: -[point](#point), -[primary key](#primary-key), -[series](#series), -[tag](#tag), -[tag key](#tag-key), -[tag value](#tag-value) - -### tag value - -The value of a tag key-value pair. -Tag values are strings and they store metadata. - -Related entries: -[tag](#tag), -[tag key](#tag-key), -[tag set](#tag-set) - -### Telegraf - -A plugin-driven agent that collects, processes, aggregates, and writes metrics. - -Related entries: -[Telegraf plugins](/telegraf/v1/plugins/), -[Use Telegraf to collect data](/influxdb3/clustered/write-data/use-telegraf/), - -### time (data type) - -A data type that represents a single point in time with nanosecond precision. - -### time series data - -Sequence of data points typically consisting of successive measurements made -from the same source over a time interval. -Time series data shows how data evolves over time. -On a time series data graph, one of the axes is always time. -Time series data may be regular or irregular. -Regular time series data changes in constant intervals. -Irregular time series data changes at non-constant intervals. - -### timestamp - -The date and time associated with a point. -Time in InfluxDB is in UTC. - -To specify time when writing data, see -[Elements of line protocol](/influxdb3/clustered/reference/syntax/line-protocol/#elements-of-line-protocol). - -Related entries: -[point](#point), -[unix timestamp](#unix-timestamp), -[RFC3339 timestamp](#rfc3339-timestamp) - -### token - -Tokens provide authorization to perform specific actions in InfluxDB. -There are different types of API tokens: - -- **Database token:** Grants read and write access to a database. -- **Management token:** A short-lived token that grants clients administrative - access to your InfluxDB cluster. - -Related entries: -[Manage token](/influxdb3/clustered/admin/tokens/) - -### transformation - -Data transformation refers to the process of converting or modifying input data from one format, value, or structure to another. - -InfluxQL [transformation functions](/influxdb3/clustered/reference/influxql/functions/transformations/) modify and return values in each row of queried data, but do not return an aggregated value across those rows. - -Related entries: [aggregate](#aggregate), [function](#function), [selector](#selector) - -### TSM (Time Structured Merge tree) - -The InfluxDB v1 and v2 data storage format that allows greater compaction and -higher write and read throughput than B+ or LSM tree implementations. -The TSM storage engine has been replaced by the [InfluxDB 3 storage engine (IOx)](#iox). - -Related entries: -[IOx](#iox) - -## U - -### UDP - -User Datagram Protocol is a packet of information. -When a request is made, a UDP packet is sent to the recipient. -The sender doesn't verify the packet is received. -The sender continues to send the next packets. -This means computers can communicate more quickly. -This protocol is used when speed is desirable and error correction is not necessary. - -### unix epoch - -The date and time from which Unix system times are measured. -The Unix epoch is `1970-01-01T00:00:00Z`. - -### unix timestamp - -Counts time since **Unix Epoch (1970-01-01T00:00:00Z UTC)** in specified units ([precision](#precision)). -Specify timestamp precision when [writing data to InfluxDB](/influxdb3/clustered/write-data/). -InfluxDB supports the following unix timestamp precisions: - -| Precision | Description | Example | -|:--------- |:----------- |:------- | -| `ns` | Nanoseconds | `1577836800000000000` | -| `us` | Microseconds | `1577836800000000` | -| `ms` | Milliseconds | `1577836800000` | -| `s` | Seconds | `1577836800` | - -

The examples above represent 2020-01-01T00:00:00Z UTC.

- -Related entries: -[timestamp](#timestamp), -[RFC3339 timestamp](#rfc3339-timestamp) - -### unsigned integer - -A whole number that is positive or zero (`0`, `143`). Also known as a "uinteger." -InfluxDB supports 64-bit unsigned integers (minimum: `0`, maximum: `18446744073709551615`). - -Related entries: -[integer](#integer) - -### user - -InfluxDB users are granted permission to access to InfluxDB. - -## V - -### values per second - -The preferred measurement of the rate at which data is persisted to InfluxDB. -Write speeds are generally quoted in values per second. - -To calculate the values per second rate, multiply the number of points written -per second by the number of values stored per point. -For example, if the points have four fields each, and a batch of 5000 points is -written 10 times per second, the values per second rate is: - -**4 field values per point** × **5000 points per batch** × **10 batches per second** = **200,000 values per second** - -Related entries: -[batch](#batch), -[field](#field), -[point](#point) - -### variable - -A storage location (identified by a memory address) paired with an associated -symbolic name (an identifier). -A variable contains some known or unknown quantity of information referred to as a value. - -### variable assignment - -A statement that sets or updates the value stored in a variable. - -## W - -### WAL (Write-Ahead Log) - -The temporary cache for recently written points. -To reduce the frequency that permanent storage files are accessed, InfluxDB -caches new points in the WAL until their total size or age triggers a flush to -more permanent storage. This allows for efficient batching of the writes into -the storage engine. - -Points in the WAL are queryable and persist through a system reboot. -On process start, all points in the WAL must be flushed before the system -accepts new writes. - -### windowing - -Grouping data based on specified time intervals. -This is also referred to as "time binning" or "date binning." +