--- title: "Refresh a materialized view" sidebarTitle: "Materialized View Refresh" description: "Create a materialized view and refresh it when the source data changes." icon: table keywords: ["materialized view", "create_materialized_view", "refresh", "full refresh"] availability: oss: available enterprise: available summary: >- Both offerings support materialized views. OSS refreshes run in your process; Enterprise runs the work on remote compute. See [Enterprise refreshes](#availability) for server compatibility requirements. --- import { PyMaterializedViewCreate as MaterializedViewCreate, PyMaterializedViewRefresh as MaterializedViewRefresh, } from '/snippets/materialized_view.mdx'; A materialized view stores the result of a query as a table. Use it to keep a filtered or transformed dataset that you can query, index and search repeatedly. Refresh the view after its source data changes. In SQL this is [`REFRESH MATERIALIZED VIEW`](/sql/refresh#refresh-materialized-view). ## Create and refresh {#create-and-refresh} {MaterializedViewCreate} Creating the view computes its rows, so it is ready to read. Pass `with_no_data=True` to create it empty instead. Later changes to the source reach the view through a refresh: {MaterializedViewRefresh} The example works with Python SDK 0.40.0. It creates the source with stable row IDs, which that release requires for ordinary materialized-view sources. `select` takes column names, `(alias, expression)` pairs, or a dict of the same. Omitting it selects every source column, expanded against the schema as it was at creation time. `where` filters source rows; `limit` caps the view. ## Prepare the source table {#stable-row-ids} In Python SDK 0.40.0, create the source with `storage_options={"new_table_enable_stable_row_ids": "true"}`, as the example above does. Stable row IDs let the view track source rows across updates and compaction. Set this option when creating the table; it cannot be added later. A source with a MemWAL write spec or retained, uncompacted write-ahead-log rows is not accepted by the local materialized-view implementation. ## Refresh behavior {#incremental} With Python SDK 0.40.0, a refresh applies source changes incrementally when the query supports it, and rebuilds the view otherwise. In the example, adding Bea writes one new view row. Refreshing again without source changes writes none. Use `refresh(full=True)` to force a rebuild. `rows_written` counts rows written by that refresh, not all rows in the view. Use `view.table.count_rows()` to get the total. Pass `source_version=N` to refresh against a particular source version instead of the latest. Refresh behavior has changed between SDK versions. The earlier 0.40.0b13 development build rebuilt every local view on refresh and did not accept `full`; 0.39.0 created views empty. Use the reference for your installed SDK when maintaining an existing pipeline. ## Enterprise refreshes {#availability} Enterprise Enterprise runs materialized-view creation and refresh on remote compute. For SQL, see [`CREATE MATERIALIZED VIEW`](/sql/ddl/materialized-view) and [`REFRESH MATERIALIZED VIEW`](/sql/dml/refresh#refresh-materialized-view). Use an SDK version supported by your Enterprise deployment. Materialized-view APIs and stored definitions have changed across releases; a local SDK example alone does not establish compatibility with an older server. Before upgrading an existing pipeline, confirm the supported refresh options and whether its views need to be recreated with your administrator. Stable row IDs and feature configuration for Enterprise sources are managed on the server. The source-table storage option in the local example does not configure the Enterprise deployment, and Python SDK 0.40.0's `create_table` on a `db://` connection does not accept `storage_options`: leave it out, and confirm with your administrator that the deployment gives new tables stable row IDs. `list_materialized_views` requests the server's view listing. On a local database it reads table schemas to find views. ## Working with the view {#working-with-the-view} `view.table` is the underlying table, for querying, indexing, or search. `view.definition` is the recorded query: the select list, predicate, and limit. Use it to inspect the query without inferring it from the rows. Both are properties; on an async view, the definition is read with `await view.definition()`. An existing view is reopened with `db.open_materialized_view(name)`. ## Related guides {#next} Derive a column instead of a whole table. Inspect the table history and read a particular version.