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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None
Description
In yesterday’s stress tests by mleich we got a crash in a kill+restart test. I started a server on the saved data directory and got the following crash:
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10.6 dbd6c6dc01228fe6e63f3f7dc695eb56ca8cd28d |
…
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2021-10-29 13:52:47 0 [Note] InnoDB: 128 rollback segments are active.
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mariadbd: /mariadb/10.6m/storage/innobase/trx/trx0trx.cc:1221: void trx_t::evict_table(table_id_t, bool): Assertion `!locked || (table->locks).start->trx == this' failed.
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This occurred while we were rolling back a DELETE operation of a SYS_INDEXES record for which NAME='\xffuidx'. The special byte '\xff' indicates that it is a stub for ADD INDEX uidx. At the same time, we had recovered a DML transaction that is holding a lock on the same user table (t1). The assertion fails, because tables must never be evicted if other transactions are holding locks on them.
With some effort, I created a repeatable test case for this:
--source include/have_innodb.inc
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# The embedded server tests do not support restarting. |
--source include/not_embedded.inc
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--source include/have_debug.inc
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--source include/have_debug_sync.inc
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connection default; |
CREATE TABLE t1(a INT PRIMARY KEY, b INT) ENGINE=InnoDB; |
INSERT INTO t1 VALUES(1,1); |
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connect ddl, localhost, root; |
SET DEBUG_SYNC = 'row_merge_after_scan SIGNAL scanned WAIT_FOR commit'; |
SET DEBUG_SYNC = 'before_commit_rollback_inplace SIGNAL c WAIT_FOR ever'; |
send ALTER TABLE t1 ADD UNIQUE INDEX(b), ALGORITHM=INPLACE; |
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connection default; |
SET DEBUG_SYNC = 'now WAIT_FOR scanned'; |
BEGIN; |
INSERT INTO t1 VALUES(2,1); |
SET DEBUG_SYNC = 'now SIGNAL commit'; |
SET DEBUG_SYNC = 'now WAIT_FOR c'; |
SET GLOBAL innodb_flush_log_at_trx_commit=1; |
INSERT INTO t1 VALUES(3,3); |
sleep 1;
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--source include/kill_mysqld.inc
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disconnect ddl;
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--source include/start_mysqld.inc
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CHECK TABLE t1; |
SHOW CREATE TABLE t1; |
SELECT * FROM t1; |
DROP TABLE t1; |
Note: I have no idea why that sleep 1 is needed. I suspect MDEV-26789 or some related changes. Is our durability broken now?
The test requires the following synchronization point:
diff --git a/storage/innobase/handler/handler0alter.cc b/storage/innobase/handler/handler0alter.cc
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index adeaf87f7fe..79a308a20a6 100644
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--- a/storage/innobase/handler/handler0alter.cc
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+++ b/storage/innobase/handler/handler0alter.cc
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@@ -8764,6 +8764,7 @@ inline bool rollback_inplace_alter_table(Alter_inplace_info *ha_alter_info,
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ut_d(dict_table_check_for_dup_indexes(ctx->old_table, CHECK_ABORTED_OK));
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}
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+ DEBUG_SYNC(ctx->trx->mysql_thd, "before_commit_rollback_inplace");
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commit_unlock_and_unlink(ctx->trx);
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if (fts_exist)
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purge_sys.resume_FTS(); |
Attachments
Issue Links
- is caused by
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MDEV-25180 Atomic ALTER TABLE
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- Closed
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