mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-11-07 16:14:52 +00:00
76 lines
2.8 KiB
Markdown
76 lines
2.8 KiB
Markdown
# system.zookeeper {#system-zookeeper}
|
||
|
||
The table does not exist if ZooKeeper is not configured. Allows reading data from the ZooKeeper cluster defined in the config.
|
||
The query must either have a ‘path =’ condition or a `path IN` condition set with the `WHERE` clause as shown below. This corresponds to the path of the children in ZooKeeper that you want to get data for.
|
||
|
||
The query `SELECT * FROM system.zookeeper WHERE path = '/clickhouse'` outputs data for all children on the `/clickhouse` node.
|
||
To output data for all root nodes, write path = ‘/’.
|
||
If the path specified in ‘path’ doesn’t exist, an exception will be thrown.
|
||
|
||
The query `SELECT * FROM system.zookeeper WHERE path IN ('/', '/clickhouse')` outputs data for all children on the `/` and `/clickhouse` node.
|
||
If in the specified ‘path’ collection has doesn't exist path, an exception will be thrown.
|
||
It can be used to do a batch of ZooKeeper path queries.
|
||
|
||
Columns:
|
||
|
||
- `name` (String) — The name of the node.
|
||
- `path` (String) — The path to the node.
|
||
- `value` (String) — Node value.
|
||
- `dataLength` (Int32) — Size of the value.
|
||
- `numChildren` (Int32) — Number of descendants.
|
||
- `czxid` (Int64) — ID of the transaction that created the node.
|
||
- `mzxid` (Int64) — ID of the transaction that last changed the node.
|
||
- `pzxid` (Int64) — ID of the transaction that last deleted or added descendants.
|
||
- `ctime` (DateTime) — Time of node creation.
|
||
- `mtime` (DateTime) — Time of the last modification of the node.
|
||
- `version` (Int32) — Node version: the number of times the node was changed.
|
||
- `cversion` (Int32) — Number of added or removed descendants.
|
||
- `aversion` (Int32) — Number of changes to the ACL.
|
||
- `ephemeralOwner` (Int64) — For ephemeral nodes, the ID of the session that owns this node.
|
||
|
||
Example:
|
||
|
||
``` sql
|
||
SELECT *
|
||
FROM system.zookeeper
|
||
WHERE path = '/clickhouse/tables/01-08/visits/replicas'
|
||
FORMAT Vertical
|
||
```
|
||
|
||
``` text
|
||
Row 1:
|
||
──────
|
||
name: example01-08-1.yandex.ru
|
||
value:
|
||
czxid: 932998691229
|
||
mzxid: 932998691229
|
||
ctime: 2015-03-27 16:49:51
|
||
mtime: 2015-03-27 16:49:51
|
||
version: 0
|
||
cversion: 47
|
||
aversion: 0
|
||
ephemeralOwner: 0
|
||
dataLength: 0
|
||
numChildren: 7
|
||
pzxid: 987021031383
|
||
path: /clickhouse/tables/01-08/visits/replicas
|
||
|
||
Row 2:
|
||
──────
|
||
name: example01-08-2.yandex.ru
|
||
value:
|
||
czxid: 933002738135
|
||
mzxid: 933002738135
|
||
ctime: 2015-03-27 16:57:01
|
||
mtime: 2015-03-27 16:57:01
|
||
version: 0
|
||
cversion: 37
|
||
aversion: 0
|
||
ephemeralOwner: 0
|
||
dataLength: 0
|
||
numChildren: 7
|
||
pzxid: 987021252247
|
||
path: /clickhouse/tables/01-08/visits/replicas
|
||
```
|
||
[Original article](https://clickhouse.tech/docs/en/operations/system_tables/zookeeper) <!--hide-->
|