[8.4] PS-9683 : Enable CHECK TABLE EXTENDED to detect InnoDB LOB corruptions #5586
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https://perconadev.atlassian.net/browse/PS-9683 Problem: -------- In some of the customer environments, it is found that an external LOB's first page is shared between two records. This shouldn't be possible. But it can happen rarely. The root cause is not known yet. Using table in state, can lead to corruption and assertion failures. Fix: --- But we can detect such a scenario by scanning all records and the external LOB's first page. the EXTENDED keyword currently is ignored by InnoDB. We use it to enable the LOB checks and mark index as corrupted if an external LOB's first page is shared between two records. A thread local blob map is used to identify the duplicate user record that has the same external LOB page. usage: ------ CHECK TABLE t1 EXTENDED A sample error log when such corruption is detected: 2025-04-11T10:30:28.078607Z 9 [ERROR] [MY-011825] [InnoDB] Invalid record! External LOB first page cannot be shared between two records 2025-04-11T10:30:28.078625Z 9 [ERROR] [MY-011825] [InnoDB] The external LOB first page is [page id: space=6, page number=347] 2025-04-11T10:30:28.078631Z 9 [ERROR] [MY-011825] [InnoDB] The first occurence of the external LOB first page is in record : page_no: 3 with heap_no: 6 2025-04-11T10:30:28.078638Z 9 [ERROR] [MY-011825] [InnoDB] The second occurence of the external LOB first page is in record: page_no: 4 with heap no: 7 2025-04-11T10:30:28.078646Z 9 [ERROR] [MY-012738] [InnoDB] Apparent corruption in space 6 page 4 index `PRIMARY` 2025-04-11T10:30:28.078663Z 9 [ERROR] [MY-013050] [InnoDB] In page 4 of index `PRIMARY` of table `test`.`t1` 2025-04-11T10:30:28.088156Z 9 [Warning] [MY-012382] [InnoDB] Cannot open table test/t1Please refer to http://dev.mysql.com/doc/refman/8.0/en/innodb-troubleshooting.html for how to resolve the issue.
satya-bodapati
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| /* true if user uses CHECK TABLE t1 EXTENDED */ | ||
| const bool is_extended = check_opt->flags & T_EXTEND; |
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implicit conversion unsigned long -> bool
Suggested change
| const bool is_extended = check_opt->flags & T_EXTEND; | |
| const bool is_extended = (check_opt->flags & T_EXTEND) != 0u; |
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| } else { | ||
| continue; | ||
| } |
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do not use else after break
Suggested change
| } else { | |
| continue; | |
| } | |
| } continue; | |
| ut_ad(!((page_offset(seg_inode) - FSEG_ARR_OFFSET) % FSEG_INODE_SIZE)); | ||
| ut_a(seg_inode); | ||
| ut_ad(mach_read_from_4(seg_inode + FSEG_MAGIC_N) == FSEG_MAGIC_N_VALUE); | ||
| ut_ad(!((page_offset(seg_inode) - FSEG_ARR_OFFSET) % FSEG_INODE_SIZE)); |
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performing an implicit widening conversion to type unsigned long of a multiplication performed in type unsigned int
| ulint n_fields = rec_offs_n_fields(offsets); | ||
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| for (ulint i = 0; i < n_fields; i++) { | ||
| if (rec_offs_nth_extern(index, offsets, i)) { |
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implicit conversion ulint (aka unsigned long) -> bool
Suggested change
| if (rec_offs_nth_extern(index, offsets, i)) { | |
| if (rec_offs_nth_extern(index, offsets, i) != 0u) { |
| if (rec_offs_nth_extern(index, offsets, i)) { | ||
| // We do const_cast to remove constness because lob::ref_t doesn't have a | ||
| // variant that takes const record pointer | ||
| byte *field_ref = const_cast<byte *>( |
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do not use const_cast
| goto func_exit; | ||
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| if (!page_rec_blob_validate(const_cast<byte *>(rec), index, offsets)) { |
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do not use const_cast
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| if (!page_rec_blob_validate(const_cast<byte *>(rec), index, offsets)) { | ||
| goto func_exit; |
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avoid using goto for flow control
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Merge 8.0 fix to 8.4