0a4a5b36cc
* Additional .gitignore entries * Merge a bunch of small articles about system tables into single one * Merge a bunch of small articles about formats into single one * Adapt table with formats to English docs too * Add SPb meetup link to main page * Move Utilities out of top level of docs (the location is probably not yet final) + translate couple articles * Merge MacOS.md into build_osx.md * Move Data types higher in ToC * Publish changelog on website alongside documentation * Few fixes for en/table_engines/file.md * Use smaller header sizes in changelogs * Group up table engines inside ToC * Move table engines out of top level too * Specificy in ToC that query language is SQL based. Thats a bit excessive, but catches eye. * Move stuff that is part of query language into respective folder * Move table functions lower in ToC * Lost redirects.txt update * Do not rely on comments in yaml + fix few ru titles * Extract major parts of queries.md into separate articles * queries.md has been supposed to be removed * Fix weird translation * Fix a bunch of links * There is only table of contents left * "Query language" is actually part of SQL abbreviation * Change filename in README.md too * fix mistype
2.5 KiB
GraphiteMergeTree
This engine is designed for rollup (thinning and aggregating/averaging) Graphite data. It may be helpful to developers who want to use ClickHouse as a data store for Graphite.
Graphite stores full data in ClickHouse, and data can be retrieved in the following ways:
-
Without thinning.
Uses the MergeTree engine.
-
With thinning.
Using the
GraphiteMergeTreeengine.
The engine inherits properties from MergeTree. The settings for thinning data are defined by the graphite_rollup parameter in the server configuration.
Using the engine
The Graphite data table must contain the following fields at minimum:
Path– The metric name (Graphite sensor).Time– The time for measuring the metric.Value– The value of the metric at the time set in Time.Version– Determines which value of the metric with the same Path and Time will remain in the database.
Rollup pattern:
pattern
regexp
function
age -> precision
...
pattern
...
default
function
age -> precision
...
When processing a record, ClickHouse will check the rules in the patternclause. If the metric name matches the regexp, the rules from pattern are applied; otherwise, the rules from default are used.
Fields in the pattern.
age– The minimum age of the data in seconds.function– The name of the aggregating function to apply to data whose age falls within the range[age, age + precision].precision– How precisely to define the age of the data in seconds.regexp– A pattern for the metric name.
Example of settings:
<graphite_rollup>
<pattern>
<regexp>click_cost</regexp>
<function>any</function>
<retention>
<age>0</age>
<precision>5</precision>
</retention>
<retention>
<age>86400</age>
<precision>60</precision>
</retention>
</pattern>
<default>
<function>max</function>
<retention>
<age>0</age>
<precision>60</precision>
</retention>
<retention>
<age>3600</age>
<precision>300</precision>
</retention>
<retention>
<age>86400</age>
<precision>3600</precision>
</retention>
</default>
</graphite_rollup>