HP Neoview Release 2.5 Software - Manual (Page 78)

Recompute
Derives the materialized view from scratch. This is used on the initial refresh of
the materialized view and also to re-derive the materialized view if it is in an
inconsistent state (for example, if the previous refresh was aborted abnormally).
—
— On Request
Updates the materialized view at a time that you schedule. This allows for fast
querying and a high update rate, but queries may read data that is not up-to-date
with underlying tables. Select this if your application can tolerate "stale" data.
— On Statement
Updates the materialized view immediately upon an update to the base tables.
This slows the transaction speed because the materialized view refresh operation
is coupled to the table update operation. Select this if your application relies on
current data.
• Initialization Type: Initialization type displayed is (On Create | On Refresh).
— On Create
Initial entries to the materialized view are made when the view is created. A
materialized view that is based on another materialized view can be initialized on
create only if:
◦
The query expression does not include joins.
◦ The underlying materialized view is already initialized.
— On Refresh
Initial entries to the materialized view are made on the first refresh after creation
(default type). The materialized view is not available to select and rewrite until it
has been refreshed.
• Refresh Commit Each: Specifies the number of rows that the refresh operation processes
before committing a transaction and processing more rows.
If an error occurs during the refresh, and the Refresh Commit Each attribute is set to a
small number of rows, fewer rows will need to be rolled back as a result of the error.
However, the smaller the value of this attribute, the greater the impact on the
performance of the refresh.
• Refreshed At Timestamp: Timestamp is in the format (yyyy-MM-dd HH:mm:ss.FFFFFF
local time).
• Creation Time: Time and date when the materialized view was created. Timestamp is
in the format (yyyy-MM-dd HH:mm:ss.FFFFFF local time).
• Redefinition Time: Time and date when the materialized view was last redefined.
Timestamp is in the format (yyyy-MM-dd HH:mm:ss.FFFFFF local time).
Partitions Tab
To display the materialized view partitions:
1. Select a Schema in the navigation tree
2. Click the Materialized Views tab in the right pane and select a materialized view name, or
open the Materialized Views folder and select a materialized view name in the tree.
3. Click the Partitions tab in the right pane.
In the right pane, these attributes are displayed:
•
Partition Number: The index number of the partition.
• Percent Allocated: The percentage full of the partition.
• Row Count: The current total number of rows in the partition.
78 Display Database Objects