clickhouse readonly

ClickHouse是一个开源的分布式列式数据库管理系统，支持超大规模数据存储和实时数据查询。ClickHouse Readonly是ClickHouse的一种查询方式，它提供了只读访问模式，不允许对数据进行修改操作。这种查询方式主要用于在生产环境中进行数据分析和报告生成等操作。ClickHouse Readonly可以实现高效、快速的查询，并具有卓越的性能表现，特别是在处理大数据量时。

相关问题

clickhouse readonly corresponding

ClickHouse supports the creation of read-only replicas of the primary cluster. These replicas can be used for read-heavy workloads to offload traffic from the primary cluster and improve query performance. To create a read-only replica, you can use the `REPLICA` keyword in the `CREATE TABLE` statement. For example:

CREATE TABLE my_table ON CLUSTER my_cluster
(
   ...
) ENGINE = ReplicatedMergeTree('/clickhouse/tables/{shard}/my_table', '{replica}')
PARTITION BY ...
ORDER BY ...
SETTINGS ...
PRIMARY KEY ...
REPLICA READONLY;

In the above example, the `REPLICA READONLY` clause creates a read-only replica of the table `my_table` on the cluster `my_cluster`. The replica is stored on the same file system as the primary cluster, but it cannot accept any write operations.

clickhouse 字段显示 readonly no corresponding table column 是什么意思

`readonly no` is an error message in ClickHouse, which is thrown when a query tries to modify a read-only column or a column that does not exist in a table. This error message can occur when:

1. You are trying to modify a column that is marked as `READONLY` in the table definition. In this case, you need to remove the `READONLY` attribute from the table definition or modify the query to exclude the read-only column.

2. You are trying to modify a column that does not exist in the table. In this case, you need to modify the query to reference a valid column in the table.

For example, the following query will throw a `readonly no` error if the `my_column` column is defined as `READONLY` or does not exist in the `my_table` table:

UPDATE my_table SET my_column = 123 WHERE id = 1;

To fix this error, you need to ensure that the `my_column` column is not read-only and exists in the `my_table` table.