Add storage policy documentation (#414)

## Summary

- Add new **Storage Policy** concept page (`concepts/storage-policy.md`)
documenting the Enterprise feature for automated partition lifecycle
management (convert to Parquet, drop native, drop local, drop remote)
- Add new **ALTER TABLE SET STORAGE POLICY** SQL reference page
(`query/sql/alter-table-set-storage-policy.md`) with full syntax,
constraints, permissions, and examples
- Add `STORAGE POLICY` clause documentation to the **CREATE TABLE**
reference page
- Update **data-retention.md** to list storage policies as a third
retention approach alongside TTL and manual `DROP PARTITION`
- Update **storage-engine.md** to reference storage policies for
automatic Parquet conversion (replacing the previous object storage
mention)
- Add cross-reference from **TTL** concept page to the new storage
policy docs
- Register both new pages in `sidebars.js`

## Test plan

- [x] Verify `yarn build` succeeds with no broken links
- [x] Check sidebar navigation includes the new pages under Concepts and
SQL Reference
- [x] Confirm cross-links between storage policy, TTL, data retention,
and CREATE TABLE pages resolve correctly

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: javier ramírez <javier@questdb.io>
Co-authored-by: Vlad Ilyushchenko <bluestreak@gmail.com>

Author: 4 people

documentation/architecture/storage-engine.md

@@ -55,9 +55,10 @@ Older partitions (any partition other than the most recent one) can be converted
 Partitions in Parquet format remain fully available for queries. Users don't need to know whether a partition is in QuestDB
 binary format or Parquet format. All the data types available in QuestDB can be converted to Parquet.
 
-When using QuestDB Enterprise, tables can be configured to convert to Parquet automatically and to send the Parquet
-files to object storage (Amazon S3, Microsoft Blob Storage, Google Cloud Storage, NFS...). This can help reduce the
-cost of storing historical data while keeping it fully available for queries.
+When using QuestDB Enterprise, tables can be configured to convert to Parquet automatically using
+[storage policies](/docs/concepts/storage-policy/). This can help reduce local disk usage
+while keeping historical data fully available for queries. Support for automatic upload
+of Parquet files to object storage will be added in a future release.
 
 
 

documentation/concepts/materialized-views.md

@@ -336,6 +336,16 @@ CREATE MATERIALIZED VIEW trades_hourly AS (
 
 The view's TTL is independent of the base table's TTL.
 
+:::note
+
+In QuestDB Enterprise, TTL is superseded by
+[storage policies](/docs/concepts/storage-policy/). Use
+[`STORAGE POLICY(...)`](/docs/query/sql/alter-mat-view-set-storage-policy/) on
+a materialized view instead of `TTL` for graduated lifecycle management
+(convert to Parquet, then drop).
+
+:::
+
 ### Initial refresh
 
 When created, materialized views start an **asynchronous full refresh**:
@@ -592,6 +602,9 @@ the replica's view was not fully up-to-date.
     Sets the time limit for incremental refresh on a materialized view
   - [`ALTER MATERIALIZED VIEW SET TTL`](/docs/query/sql/alter-mat-view-set-ttl/):
     Sets the time-to-live (TTL) period on a materialized view
+  - [`ALTER MATERIALIZED VIEW SET STORAGE POLICY`](/docs/query/sql/alter-mat-view-set-storage-policy/):
+    Attaches a [storage policy](/docs/concepts/storage-policy/) to a
+    materialized view (QuestDB Enterprise)
 
 - **Configuration**
   - [Materialized views configs](/docs/configuration/overview/#materialized-views):

documentation/concepts/partitions.md

@@ -189,3 +189,5 @@ partition as a single unit.
 - [DETACH PARTITION](/docs/query/sql/alter-table-detach-partition/) — Move to cold storage
 - [ATTACH PARTITION](/docs/query/sql/alter-table-attach-partition/) — Restore detached data
 - [TTL](/docs/concepts/ttl/) — Automatic partition cleanup by age
+- [Storage Policy](/docs/concepts/storage-policy/) — Graduated partition
+  lifecycle (convert to Parquet, then drop) in QuestDB Enterprise