MDEV-38079: Crash Recovery Fails After ALTER TABLE…PAGE_COMPRESSED=1 #4565
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Issue: Recovery fails because the expected space ID does not match the space ID stored in the page. Root Cause: - Before the crash, the nth page (n != 0) gets flushed to disk as a compressed page. - Page 0 remains unflushed, and the compressed flag for the space is made durable only in the redo logs. - During recovery, the compressed flag is first set to indicate a compressed space. - Later, while applying redo logs on page 0, an earlier LSN may reset it to non-compressed and then back to compressed. - If the nth page is read during this intermediate state, a compressed page may be read as non-compressed, causing a space ID mismatch. Fix: - recv_sys_t::space_flags_lsn : Added a map to track the last applied LSN for each space and avoid stale updates from earlier LSNs. - recv_sys_t::update_space_flags() : Updates space->flags during recovery only if the update comes from the latest LSN.
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Opened PR-4586 based against 10.6 |
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Description
Issue:
Recovery fails because the expected space ID does not match the space
ID stored in the page.
Root Cause:
compressed page.
made durable only in the redo logs.
compressed space.
non-compressed and then back to compressed.
page may be read as non-compressed, causing a space ID mismatch.
Fix:
LSN for each space and avoid stale updates from earlier LSNs.
recovery only if the update comes from the latest LSN.
How can this PR be tested?
Tested with the data directory mentioned in the Jira ticket.
Basing the PR against the correct MariaDB version