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Apache Zookeeper

What is Zookeeper ?

ZooKeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services. All of these kinds of services are used in some form or another by distributed applications. Each time they are implemented there is a lot of work that goes into fixing the bugs and race conditions that are inevitable.

Environment


!!! note

If you need to use this data source, you need to upgrade the DataCap service to >= `1.5.x`

Support Time: 2023-02-07

SQL statement syntax


This chapter describes the SQL syntax used in Zookeeper on DataCap.

SELECT

!!! note "Synopsis"

SELECT [ * | <Columns> ] select_expression [, ...]
FROM from_item [. ...]

where from_item is one of

table_name [ `a.b` | a.b | `a`.`b`]

!!! danger

When `table_name` is set to `all` the root directory is searched.

!!! note "Select expressions"

Each select_expression must be in one of the following forms:

expression [ column_alias ]
*

In the case of expression [ column_alias ], a single output column is defined.

In the case of *, all columns of the relation defined by the query are included in the result set.

    *
--------
   data

!!! danger

If it is a multi-level directory, such as `/zookeeper/id/2`, it will be written **\`zookeeper\`.\`id\`.\`2\`**, and use `.` to split between directories.

Configure


DataCap uses configuration files by default zookeeper.json

!!! note

If your Zookeeper service version requires other special configurations, please refer to modifying the configuration file and restarting the DataCap service.

=== "Configure"

| Field  |             Required              | Default Value |
|:------:|:---------------------------------:|:-------------:|
| `Name` | :material-check-circle: { .red }  |       -       |
| `Host` | :material-check-circle:  { .red } |  `127.0.0.1:2181`  |
| `Port` | :material-close-circle:           |    `1`     |

Version (Validation)


!!! warning

The online service has not been tested yet, if you have detailed test results, please submit [issues](https://github.com/EdurtIO/datacap/issues/new/choose) to us
  • 3.1.x - 3.7.x