mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-17 13:13:36 +00:00
86 lines
2.5 KiB
Markdown
Executable File
86 lines
2.5 KiB
Markdown
Executable File
<a name="table_engines-graphitemergetree"></a>
|
||
|
||
# GraphiteMergeTree
|
||
|
||
This engine is designed for rollup (thinning and aggregating/averaging) [Graphite](http://graphite.readthedocs.io/en/latest/index.html) 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](mergetree.md#table_engines-mergetree) engine.
|
||
|
||
- With thinning.
|
||
|
||
Using the `GraphiteMergeTree` engine.
|
||
|
||
The engine inherits properties from MergeTree. The settings for thinning data are defined by the [graphite_rollup](../operations/server_settings/settings.md#server_settings-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:
|
||
|
||
```text
|
||
pattern
|
||
regexp
|
||
function
|
||
age -> precision
|
||
...
|
||
pattern
|
||
...
|
||
default
|
||
function
|
||
age -> precision
|
||
...
|
||
```
|
||
|
||
When processing a record, ClickHouse will check the rules in the `pattern`clause. 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:
|
||
|
||
```xml
|
||
<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>
|
||
```
|