Materialize

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Command #

Materialize <json_spec>

Description #

Materialize is a low level vreplication API that allows for generalized materialization of tables. The target tables can be copies, aggregations or views. The target tables are kept in sync in near-realtime.

You can specify multiple tables to materialize using the json_spec parameter.

Parameters #

JSON spec details #

  • workflow name to refer to this materialization
  • source_keyspace keyspace containing the source table
  • target_keyspace keyspace to materialize to
  • table_settings list of views to be materialized and the associated query
    • target_table name of table to which to materialize the data to
    • source_expression the materialization query

Example #

Materialize '{"workflow": "product_sales", "source_keyspace": "commerce", "target_keyspace": "customer", 
    "table_settings": [{"target_table": "sales_by_sku", 
    "source_expression": "select sku, count(*), sum(price) from corder group by order_id"}]}'

A Materialize Workflow #

Once you decide on your materialization requirements, you need to initiate a VReplication workflow as follows:

  1. Initiate the migration using Materialize
  2. Monitor the workflow using Workflow or VExec
  3. Start accessing your views once the workflow has started Replicating

Notes #

There are special commands to perform common materialization tasks and you should prefer them to using Materialize directly.

  • If you just want to copy tables to a different keyspace use MoveTables.
  • If you want to change sharding strategies use Reshard instead
Materialize