Fix loss of root/meta blkno after self-invalidation; defer invalidation processing under page locks#55
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…on processing under page locks Fix an issue where B-tree descriptor state (`metaPageBlkno` and `rootPageBlkno`) could be lost after processing an invalidation message within the same transaction. Previously, after `o_btree_load_shmem()` initialized the descriptor, a invalidation message could be processed before the descriptor was used. This caused the descriptor to be recreated, resetting `metaPageBlkno` and `rootPageBlkno` to `InvalidBlockNumber`, which led to assertion failures (e.g. in `btree_ctid_get_and_inc`). While investigating, another problem was identified: invalidation message processing may occur while holding page locks. Invalidation handlers access system trees, and if required pages are evicted, they trigger page loads. This leads to `load_page()` being called while locks are held, hitting assertions that forbid holding locks during page load. To address both issues: * Ensure descriptor state is not lost due to mid-operation self-invalidation * Introduce deferred invalidation handling: * Skip invalidation message processing when it is unsafe (e.g. while holding page locks) * Process pending invalidation messages at the next safe point This prevents descriptor corruption and avoids unsafe page loads under locks.
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Fix an issue where B-tree descriptor state (
metaPageBlknoandrootPageBlkno) could be lost after processing an invalidation message within the same transaction.Previously, after
o_btree_load_shmem()initialized the descriptor, a invalidation message could be processed before the descriptor was used. This caused the descriptor to be recreated, resettingmetaPageBlknoandrootPageBlknotoInvalidBlockNumber, which led to assertion failures (e.g. inbtree_ctid_get_and_inc).While investigating, another problem was identified: invalidation message processing may occur while holding page locks. Invalidation handlers access system trees, and if required pages are evicted, they trigger page loads. This leads to
load_page()being called while locks are held, hitting assertions that forbid holding locks during page load.To address both issues:
Ensure descriptor state is not lost due to mid-operation self-invalidation
Introduce deferred invalidation handling:
This prevents descriptor corruption and avoids unsafe page loads under locks.
downlink -> orioledb/orioledb#792