Only REFRESH CONCURRENTLY if view populated? #407
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Does this fail if the view isn't yet populated? In any event, I'm not sure silently falling back to a non-concurrent refresh would be best. Thoughts @calebhearth? |
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You can refresh a view that’s not yet populated. Probably the first thing you’d do with the newly created but not yet populated view :) |
| @@ -214,7 +214,7 @@ def refresh_materialized_view(name, concurrently: false, cascade: false) | |||
| refresh_dependencies_for(name, concurrently: concurrently) | |||
| end | |||
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| if concurrently | |||
| if concurrently && populated?(name) | |||
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We may want to update the docs above to mention that even if the value of concurrently is true, we won't refresh concurrently if a view is unpopulated.
Here's a reproduction of the problem being solved here, which would be nice to have a test added for:
caleb=# CREATE MATERIALIZED VIEW testing AS (SELECT unnest('{1, 2}'::int[])) WITH NO DATA;
CREATE MATERIALIZED VIEW
Time: 17.382 ms
caleb=# select * from testing;
ERROR: materialized view "testing" has not been populated
HINT: Use the REFRESH MATERIALIZED VIEW command.
Time: 4.597 ms
caleb=# REFRESH MATERIALIZED VIEW CONCURRENTLY testing;
ERROR: CONCURRENTLY cannot be used when the materialized view is not populated
caleb=# REFRESH MATERIALIZED VIEW testing;
REFRESH MATERIALIZED VIEW
Time: 8.110 ms
caleb=# SELECT * FROM testing;
unnest
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1
2
(2 rows)
Time: 1.345 msThere was a problem hiding this comment.
caleb=# REFRESH MATERIALIZED VIEW CONCURRENTLY testing;
ERROR: cannot refresh materialized view "public.testing" concurrently
HINT: Create a unique index with no WHERE clause on one or more columns of the materialized view.
Time: 1.029 mssilently falling back to a non-concurrent refresh
In the case that the view is already populated, we're avoiding raising an error but agreed that it might actually be desirable to raise that error in this case, to avoid long queries blocking a table unexpectedly
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