Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Fixed
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10.5, 10.6, 10.11, 10.3(EOL), 10.4(EOL), 10.7(EOL), 10.8(EOL), 10.9(EOL), 10.10(EOL), 11.0(EOL)
Description
jeanfrancois.gagne provided a copy of a page of a ROW_FORMAT=COMPRESSED page on which an attempt to execute the following:
BEGIN; |
DELETE FROM t WHERE pk=123; |
ROLLBACK; |
would lead to the following crash:
10.6 32a53a66df0369a446db1e41f5123afe62e793fb |
2023-03-20 11:09:00 0x7f427c2026c0 InnoDB: Assertion failure in file /mariadb/10.6/storage/innobase/row/row0umod.cc line 130
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InnoDB: Failing assertion: !dummy_big_rec
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InnoDB: We intentionally generate a memory trap.
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InnoDB: Submit a detailed bug report to https://jira.mariadb.org/
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…
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#7 0x0000558b2197f2e3 in ut_dbg_assertion_failed (expr=expr@entry=0x558b20cfd8b8 "!dummy_big_rec", file=file@entry=0x558b20d6ea78 "/mariadb/10.6/storage/innobase/row/row0umod.cc", line=line@entry=130) at /mariadb/10.6/storage/innobase/ut/ut0dbg.cc:60
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#8 0x0000558b2194a7fb in row_undo_mod_clust_low (node=node@entry=0x7f422002d698, offsets=offsets@entry=0x7f427c200178, offsets_heap=offsets_heap@entry=0x7f427c200170, heap=0x7f4220031b10, sys=sys@entry=0x7f427c2001d3 "|B\177", thr=thr@entry=0x7f422004faf0, mtr=<optimized out>, mode=<optimized out>) at /mariadb/10.6/storage/innobase/row/row0umod.cc:130
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The reason for this crash is a misguided check in btr_cur_update_in_place() that unnecessarily causes btr_cur_pessimistic_update() to be invoked during the ROLLBACK operation.
Back in 2005, I specifically designed the ROW_FORMAT=COMPRESSED format in such a way that a delete or the rollback of a delete would always succeed, as would purging the history of a delete-marked record. The "deleted" as well as the "freed" flags are stored in a bit in the dense page directory at the end of the compressed page. This is the reason why the uncompressed page size is limited to 16384 bytes when using ROW_FORMAT=COMPRESSED. The clustered index fields DB_TRX_ID, DB_ROLL_PTR will be stored in uncompressed format right before the page directory. Thus, both a DELETE and ROLLBACK can be executed without touching any compressed data.
Attachments
Issue Links
- relates to
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MDEV-32174 ROW_FORMAT=COMPRESSED table corruption due to ROLLBACK
- In Testing
- mentioned in
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