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add missing ` for REFRESH MATERIALIZED VIEW (#148)

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Li 2025-08-06 15:09:58 +08:00 committed by GitHub
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@ -120,7 +120,7 @@ pgivm.refresh_immv(immv_name text, with_data bool) RETURNS bigint
`refresh_immv` completely replaces the contents of an IMMV as `REFRESH MATERIALIZED VIEW` command does for a materialized view. To execute this function you must be the owner of the IMMV (with PostgreSQL 16 or earlier) or have the `MAINTAIN` privilege on the IMMV (with PostgreSQL 17 or later). The old contents are discarded.
The with_data flag is corresponding to `WITH [NO] DATA` option of REFRESH MATERIALIZED VIEW` command. If with_data is true, the backing query is executed to provide the new data, and if the IMMV is unpopulated, triggers for maintaining the view are created. Also, a unique index is created for IMMV if it is possible and the view doesn't have that yet. If with_data is false, no new data is generated and the IMMV become unpopulated, and the triggers are dropped from the IMMV. Note that unpopulated IMMV is still scannable although the result is empty. This behaviour may be changed in future to raise an error when an unpopulated IMMV is scanned.
The with_data flag is corresponding to `WITH [NO] DATA` option of `REFRESH MATERIALIZED VIEW` command. If with_data is true, the backing query is executed to provide the new data, and if the IMMV is unpopulated, triggers for maintaining the view are created. Also, a unique index is created for IMMV if it is possible and the view doesn't have that yet. If with_data is false, no new data is generated and the IMMV become unpopulated, and the triggers are dropped from the IMMV. Note that unpopulated IMMV is still scannable although the result is empty. This behaviour may be changed in future to raise an error when an unpopulated IMMV is scanned.
`refresh_immv` acquires `AccessExclusiveLock` on the view. However, even if we are able to acquire the lock, a concurrent transaction may have already incrementally updated and committed the view before we can acquire the lock. In `REPEATABLE READ` or `SERIALIZABLE` isolation level, this could lead to an inconsistent state of the view. Therefore, an error is raised to prevent anomalies when this situation is detected.