AshScylla.DataLayer.FilterValidator (AshScylla v0.3.0)

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Validates that filter columns are queryable in ScyllaDB/Cassandra.

ScyllaDB/Cassandra requires that WHERE clause columns are either:

  • Part of the primary key
  • Have a secondary index defined

Filtering on non-indexed columns would require ALLOW FILTERING, which is an anti-pattern that causes full cluster scans. This module catches such issues at query-build time and provides actionable error messages.

Summary

Functions

queryable_columns(resource)

Returns the list of columns that are safe to filter on for a resource.

validate_filters(resource, filters)

Validates that all filter columns on a resource are queryable.

Functions

queryable_columns(resource)

@spec queryable_columns(module()) :: [atom()]

Returns the list of columns that are safe to filter on for a resource.

validate_filters(resource, filters)

@spec validate_filters(module(), list()) :: :ok | no_return()

Validates that all filter columns on a resource are queryable.

Returns :ok if all filters are on primary key columns or indexed columns. Raises AshScylla.Error with an actionable message if a filter would require ALLOW FILTERING.

Parameters

  • resource - The Ash resource module
  • filters - List of Ash filter expressions

Examples

AshScylla.DataLayer.FilterValidator.validate_filters(MyApp.User, filters)
# => :ok

AshScylla.DataLayer.FilterValidator.validate_filters(MyApp.User, [{:non_indexed_col, :eq, "value"}])
# => raises AshScylla.Error with suggestion to add secondary_index