What?

The shard Cassandra data type and shard column in Cassandra executions table is deprecated in favor of data and data_encoding field.

Why?

The process to introduce new field to existing data type is quite tedious because we need to update the corresponding Cassandra data type.

How?

1. Update server to v1.3.1 or a newer version

2. Set this dynamic configuration value to true

   • history.readNoSQLShardFromDataBlob

3. Check the metrics with these tags:

   • operation: getshard
   • name: nosql_shard_store_read_from_original_column OR nosql_shard_store_read_from_data_blob

   These metrics are only emitted during service start time, and after migration you should only see metrics with name:nosql_shard_store_read_from_data_blob tag.

Status

Starting from 1.3.4, the default value of history.readNoSQLShardFromDataBlob is set to true. And we're planning to remove this dynamic config in later version.