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01c724b9be
Fix a crash that could corrupt indexes when running VACUUM FULL pg_class. The crash happens when caches are queried/updated within a cache invalidation function, which can lead to corruption and recursive cache invalidations. To solve the issue, make sure the relcache invalidation callback is simple and never invokes the relcache or syscache directly or indirectly. Some background: The extension is preloaded and thus have planner hooks installed irrespective of whether the extension is actually installed or not in the current database. However, the hooks need to be disabled as long as the extension is not installed. To avoid always having to dynamically check for the presence of the extension, the state is cached in the session. However, the cached state needs to be updated if the extension changes (altered/dropped/created). Therefore, the relcache invalidation callback mechanism is (ab)used in TimescaleDB to signal updates to the extension state across all active backends. The signaling is implemented by installing a dummy table as part of the extension and any invalidation on the relid for that table signals a change in the extension state. However, as of this change, the actual state is no longer determined in the callback itself, since it requires use of the relcache and causes the bad behavior. Therefore, the only thing that remains in the callback after this change is to reset the extension state. The actual state is instead resolved on-demand, but can still be cached when the extension is in the installed state and the dummy table is present with a known relid. However, if the extension is not installed, the extension state can no longer be cached as there is no way to signal other backends that the state should be reset when they don't know the dummy table's relid, and cannot resolve it from within the callback itself. Fixes #3924
14 lines
431 B
C
14 lines
431 B
C
/*
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* This file and its contents are licensed under the Apache License 2.0.
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* Please see the included NOTICE for copyright information and
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* LICENSE-APACHE for a copy of the license.
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*/
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#ifndef TIMESCALEDB_CACHE_INVALIDATE_H
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#define TIMESCALEDB_CACHE_INVALIDATE_H
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#include <postgres.h>
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extern void ts_cache_invalidate_set_proxy_tables(Oid hypertable_proxy_oid, Oid bgw_proxy_oid);
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#endif /* TIMESCALEDB_CACHE_INVALIDATE_H */
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