Shadow :: ShardingSphere

Shadow

The Shadow MCP feature plugin helps users plan, review, apply, and validate shadow rules, default shadow algorithms, and safe cleanup of unused shadow algorithms. It generates shadow rule DistSQL only. It does not create shadow databases or physical tables, and it does not generate physical DDL, index DDL, migration, backfill, data probes, physical metadata probes, or storage unit mutation tasks.

Prerequisites

The target runtimeDatabases entry should connect to ShardingSphere-Proxy.
Source and shadow storage units must already exist.
Cleanup planning reads Proxy-visible rule, table-rule, default-algorithm, and configured-algorithm state before generating DROP SHADOW ALGORITHM.

Natural language examples

List configured shadow rules and shadow algorithm plugins in <logic-database>.
Plan a shadow rule for table t_order using source storage unit ds_0, shadow storage unit ds_shadow, and a column-match algorithm.
Drop unused shadow algorithm shadow_by_user_id only if Proxy-visible state proves it is unused.

Review checklist

Confirm that rule plans use shadow DistSQL and reference existing storage units.
Confirm that default algorithm plans update only the default shadow algorithm.
Review algorithm_recommendations before selecting a shadow algorithm. SQL_HINT has no required properties.
VALUE_MATCH requires operation, column, and value; REGEX_MATCH requires operation, column, and regex.
Confirm cleanup plans include evidence that the target algorithm is unused.
Confirm the returned plan_id, resources_to_read, next_actions, and distsql_artifacts before applying the workflow.

For the general review flow of rule changes, see Rule Change Flow.

Limitations

Supports ShardingSphere-Proxy logical databases only.
Does not create shadow databases, physical tables, or storage units.
Cleanup is limited to DistSQL-visible unused shadow algorithms.
Object name content must not contain backticks, NUL, carriage returns, or line feeds.