docs(influxdb3): clarify retention period constraints and zero-duration behavior

- Add retention period constraints warning (minimum 1h, zero-duration behavior, infinite retention)
- Restructure databases/create.md and tables/create.md with retention examples in tool sections
- Add Explorer preface instructions to delete.md and list.md
- Distinguish Enterprise (table-level) vs Core (database-level) retention capabilities
- Update data-retention.md internals documentation with constraints

content/shared/influxdb3-admin/databases/_index.md

@@ -23,8 +23,8 @@ point is marked for deletion and is removed from the database the next time the
 retention enforcement service runs.
 
 By default, data does not expire. When you [create a database](/influxdb3/version/admin/databases/create/),
-you can optionally set a retention period. Retention periods can be as short as an hour
-or infinite (`none`).
+you can optionally set a retention period.
+The minimum practical retention period is 1 hour (`1h`).
 
 Database retention periods can be [updated after creation](/influxdb3/version/reference/cli/influxdb3/update/database/).
 For tables within a database, you can [set table-specific retention periods](/influxdb3/version/admin/tables/create/#create-a-table-with-a-retention-period)
@@ -44,8 +44,8 @@ When a point's timestamp is beyond the retention period (relative to now), the
 point is not queryable and will be deleted.
 
 By default, data does not expire. When you [create a database](/influxdb3/version/admin/databases/create/),
-you can optionally set a retention period. Retention periods can be as short as one hour
-(`1h`) or infinite (`none`).
+you can optionally set a retention period.
+The minimum practical retention period is 1 hour (`1h`).
 
 For complete details about retention periods, including duration formats and limitations,
 see [Data retention in {{< product-name >}}](/influxdb3/version/reference/internals/data-retention/).

content/shared/influxdb3-admin/databases/create.md

@@ -148,7 +148,6 @@ By default, data does not expire. When creating a database, set a _retention per
 The retention period value is a time duration value made up of a numeric value
 plus a duration unit.
 For example, `30d` means 30 days.
-A zero duration (`0d`) retention period is infinite and data won't expire.
 The retention period value cannot be negative or contain whitespace.
 
 #### Valid durations units include
@@ -160,6 +159,15 @@ The retention period value cannot be negative or contain whitespace.
 - **mo**: month
 - **y**: year
 
+> [!Warning]
+> #### Retention period constraints
+>
+> - **Minimum for data retention**: The practical minimum retention period is 1 hour (`1h`).
+> - **Zero-duration periods**: Setting a retention period to `0<unit>` (for example,
+>   `0d` or `0h`) is allowed but marks all data for immediate deletion at query time.
+>   _This differs from InfluxDB 1.x and 2.x where `0d` meant infinite retention._
+> - **Infinite retention**: Use `none` to set an infinite retention period.
+
 For more information about retention periods, see [Data retention](/influxdb3/version/reference/internals/data-retention/).
 
 {{% show-in "core" %}}

content/shared/influxdb3-admin/tables/create.md

@@ -178,7 +178,6 @@ This allows you to maintain different retention policies for different types of
 The retention period value is a time duration value made up of a numeric value
 plus a duration unit.
 For example, `7d` means 7 days.
-A zero duration (`0d`) retention period is infinite and data won't expire.
 The retention period value cannot be negative or contain whitespace.
 
 #### Valid durations units include
@@ -190,6 +189,15 @@ The retention period value cannot be negative or contain whitespace.
 - **mo**: month
 - **y**: year
 
+> [!Warning]
+> #### Retention period constraints
+>
+> - **Minimum for data retention**: The practical minimum retention period is 1 hour (`1h`).
+> - **Zero-duration periods**: Setting a retention period to `0<unit>` (for example,
+>   `0d` or `0h`) is allowed but marks all data for immediate deletion at query time.
+>   _This differs from InfluxDB 1.x and 2.x where `0d` meant infinite retention._
+> - **Infinite retention**: Use `none` to set an infinite retention period.
+
 ### Retention period precedence
 
 When both a database and a table have retention periods defined, the **table retention
@@ -213,7 +221,7 @@ For complete details about retention period precedence and behavior, see
 
 In {{< product-name >}}, tables use the database retention period.
 
-When data in a table exceeds the database retention period, it is no longer queryable.
+Points with timestamps outside of the database's retention period are no longer queryable and are marked for deletion.
 To control data retention for your tables, set a retention period when [creating the database](/influxdb3/version/admin/databases/create/#retention-period).
 
 For more information, see [Data retention in {{% product-name %}}](/influxdb3/version/reference/internals/data-retention/).

content/shared/influxdb3-cli/create/database.md

@@ -142,9 +142,16 @@ values using a numeric value plus a duration unit.
 | `y`  | year (365 days) |
 
 > [!Note]
+> Minute (`m`) and second (`s`) units are not supported for retention periods.
+
+> [!Warning]
+> #### Retention period constraints
+>
 > - **Minimum for data retention**: The practical minimum retention period is 1 hour (`1h`).
->   Setting `0<unit>` (for example, `0d`) marks all data for immediate deletion.
-> - **Unsupported units**: Minute (`m`) and second (`s`) units are not supported.
+> - **Zero-duration periods**: Setting a retention period to `0<unit>` (for example,
+>   `0d` or `0h`) is allowed but marks all data for immediate deletion at query time.
+>   _This differs from InfluxDB 1.x and 2.x where `0d` meant infinite retention._
+> - **Infinite retention**: Use `none` to set an infinite retention period.
 
 ### Example duration values
 

content/shared/influxdb3-internals/data-retention.md

@@ -76,7 +76,7 @@ be negative or contain whitespace.
 > - **Minimum for data retention**: The practical minimum retention period is 1 hour (`1h`).
 > - **Zero-duration periods**: Setting a retention period to `0<unit>` (for example,
 >   `0d` or `0h`) is allowed but marks all data for immediate deletion at query time.
->   This differs from InfluxDB 1.x and 2.x where `0d` meant infinite retention.
+>   _This differs from InfluxDB 1.x and 2.x where `0d` meant infinite retention._
 > - **Infinite retention**: Use `none` to set an infinite retention period.
 
 ### Example retention period values
@@ -163,17 +163,7 @@ Replace the following:
 - {{% code-placeholder-key %}}`AUTH_TOKEN`{{% /code-placeholder-key %}}: your {{% token-link "admin" %}}
 
 {{% show-in "core" %}}
-## Retention period limitations
 
-{{< product-name >}} has the following limitations for retention periods:
-
-- **Immutable**: Retention periods cannot be changed after a database is created.
-  To change the retention period, you must create a new database and migrate your data.
-- **Database-only**: Retention periods apply to entire databases.
-- **Minimum for data retention**: The practical minimum retention period is 1 hour (`1h`).
-  Setting `0<unit>` is allowed but marks all data for immediate deletion.
-- **Query-time enforcement**: Data beyond the retention period is filtered from queries
-  but may still exist in storage until the retention enforcement service runs.
 
 > [!Note]
 > #### Retention periods are immutable in Core