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74 lines
2.2 KiB
Markdown
74 lines
2.2 KiB
Markdown
# system.zookeeper
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Allows reading data from the ZooKeeper cluster defined in the config.
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The query must have a 'path' equality condition in the WHERE clause. This is the path in ZooKeeper for the children that you want to get data for.
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The query `SELECT * FROM system.zookeeper WHERE path = '/clickhouse'` outputs data for all children on the `/clickhouse` node.
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To output data for all root nodes, write path = '/'.
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If the path specified in 'path' doesn't exist, an exception will be thrown.
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Columns:
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```text
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name String - Name of the node.
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path String - Path to the node.
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value String - Value of the node.
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dataLength Int32 - Size of the value.
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numChildren Int32 - Number of children.
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czxid Int64 - ID of the transaction that created the node.
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mzxid Int64 - ID of the transaction that last changed the node.
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pzxid Int64 - ID of the transaction that last added or removed children.
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ctime DateTime - Time of node creation.
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mtime DateTime - Time of the last node modification.
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version Int32 - Node version - the number of times the node was changed.
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cversion Int32 - Number of added or removed children.
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aversion Int32 - Number of changes to ACL.
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ephemeralOwner Int64 - For ephemeral nodes, the ID of the session that owns this node.
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```
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Example:
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```sql
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SELECT *
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FROM system.zookeeper
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WHERE path = '/clickhouse/tables/01-08/visits/replicas'
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FORMAT Vertical
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```
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```text
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Row 1:
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──────
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name: example01-08-1.yandex.ru
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value:
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czxid: 932998691229
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mzxid: 932998691229
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ctime: 2015-03-27 16:49:51
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mtime: 2015-03-27 16:49:51
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version: 0
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cversion: 47
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aversion: 0
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ephemeralOwner: 0
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dataLength: 0
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numChildren: 7
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pzxid: 987021031383
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path: /clickhouse/tables/01-08/visits/replicas
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Row 2:
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──────
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name: example01-08-2.yandex.ru
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value:
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czxid: 933002738135
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mzxid: 933002738135
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ctime: 2015-03-27 16:57:01
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mtime: 2015-03-27 16:57:01
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version: 0
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cversion: 37
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aversion: 0
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ephemeralOwner: 0
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dataLength: 0
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numChildren: 7
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pzxid: 987021252247
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path: /clickhouse/tables/01-08/visits/replicas
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```
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