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53 lines
1.8 KiB
Markdown
53 lines
1.8 KiB
Markdown
---
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layout: page
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title: "History support"
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description: "Instructions how to enable history support for Home Assistant."
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date: 2015-03-23 19:59
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sidebar: false
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comments: false
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sharing: true
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footer: true
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---
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This component will track everything that is going on within Home Assistant and allows the user to browse through it.
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```yaml
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# Example configuration.yaml entry
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history:
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```
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<p class='img'>
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<a href='{{site_root}}/images/screenshots/component_history_24h.png'>
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<img src='{{site_root}}/images/screenshots/component_history_24h.png' />
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</a>
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</p>
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<p class='note'>
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Events are saved in a local database. Google Graphs is used to draw the graph. Drawing is happening 100% in your browser - no data is transferred to anyone at any time.
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</p>
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### Implementation details
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The history is stored in a SQLite databse `home-assistant.db` within your config directory.
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- events table is all events except time_changed that happened while recorder component was running.
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- states table contains all the new_state values of state_changed events.
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- Inside the states table you have:
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- entity_id: the entity_id of the entity
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- state: the state of the entity
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- attributes: JSON of the state attributes
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- last_changed: timestamp last time the state has changed. A state_changed event can happen when just attributes change.
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- last_updated: timestamp anything has changed (state, attributes)
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- created: timestamp this entry was inserted into the database
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When the history component queries the states table it only selects states where the state has changed: `WHERE last_changed=last_updated`
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#### On dates
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SQLite databases do not support native dates. That's why all the dates are saved in seconds since the UNIX epoch. Convert them manually using this site or in Python:
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```python
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from datetime import datetime
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datetime.fromtimestamp(1422830502)
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```
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