May 2013 archive

How to remove dead node out of the Cassandra cluster?

This tutorial will helps you to remove unused / dead node from the cassandra cluster ring. Run the following command in console to list the cluster node ring formation. [code] nodetool -h <cluster-ip1> ring [/code] Results of the command it list details as like below: [code] Note: Ownership information does not include topology, please specify …

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Permanent link to this article: https://blog.openshell.in/2013/05/how-to-remove-dead-node-out-of-the-cassandra-cluster/

Mysql GROUP_CONCAT

MySQL has useful extention to the GROUP BY operation – function GROUP_CONCAT: GROUP_CONCAT(expr) – This function returns a string result with the concatenated non-NULL values from a group. Returns NULL when there are no non-NULL values. Where it can be useful? For example to get array without looping inside the code, In single SQL query …

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Permanent link to this article: https://blog.openshell.in/2013/05/mysql-group_concat/