Stored query results in materialized view are not automatically updated to reflect the latest state of the table(s) they query. The REFRESH statement updates the stored query results of a materialized view.
CockroachDB does not support materialized views that are refreshed on transaction commit.
Required privileges
The user must be the owner of the materialized view or have admin privileges.
Synopsis
Parameters
| Parameter | Description |
|---|---|
opt_concurrently |
CONCURRENTLY (Default behavior) This keyword has no effect. It is present for PostgreSQL compatibility. All materialized views are refreshed concurrently with other jobs. |
view_name |
The name of the materialized view to refresh. |
opt_clear_data |
WITH DATA (Default behavior) Refresh the stored query results. WITH NO DATA Drop the query results of the materialized view from storage. |
Example
The following example uses the sample bank database, populated with some workload values.
Suppose that you create a materialized view on the bank table:
> CREATE MATERIALIZED VIEW overdrawn_accounts
AS SELECT id, balance
FROM bank
WHERE balance < 0;
> SELECT * FROM overdrawn_accounts;
id | balance
------+----------
1 | -17643
3 | -5928
13 | -3700
...
(402 rows)
Now suppose that you update the balance values of the bank table:
> UPDATE bank SET balance = 0 WHERE balance < 0;
UPDATE 402
The changes can be seen in the table with a simple SELECT statement against the table:
> SELECT id, balance
FROM bank
WHERE balance < 0;
id | balance
-----+----------
(0 rows)
Recall that materialized views do not automatically update their stored results. Selecting from overdrawn_accounts returns stored results, which are outdated:
> SELECT * FROM overdrawn_accounts;
id | balance
------+----------
1 | -17643
3 | -5928
13 | -3700
...
(402 rows)
To update the materialized view's results, use a REFRESH statement:
> REFRESH MATERIALIZED VIEW overdrawn_accounts;
> SELECT * FROM overdrawn_accounts;
id | balance
-----+----------
(0 rows)
See also
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