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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10.1.11
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Linux 64
Description
FLUSH TABLES WITH READ LOCK on one node appears to lock other nodes as well.
In a 3 nodes Galera cluster if I do FTWRL on one node and apply simple DDL or DML on other nodes I don't have any locking.
To reproduce the issue I used a trivial mysqlslap test:
- on my node 1
$ mysqlslap --concurrency=10 --iterations=200 --number-int-cols=2 --number-char-cols=3 --auto-generate-sql -uroot -h127.0.0.1 -P10021
With this as soon as FTWRL is executed on another node, say 3, all threads of mysqlslap on node 1 will hang with something like:
{{
| 519 | root | localhost:46438 | mysqlslap | Query | 4 | query end | INSERT INTO t1 VALUES (2101913295,1100418235,'XQ0K9x30cYaFq2RvMZzKHKgmxy4uKBpreh4fX7f7XEEM8a9Nz8jGKF | 0.000 | |
| 520 | root | localhost:46440 | mysqlslap | Query | 4 | query end | INSERT INTO t1 VALUES (2101913295,1100418235,'XQ0K9x30cYaFq2RvMZzKHKgmxy4uKBpreh4fX7f7XEEM8a9Nz8jGKF | 0.000 | |
| 521 | root | localhost:46442 | mysqlslap | Query | 4 | query end | INSERT INTO t1 VALUES (2101913295,1100418235,'XQ0K9x30cYaFq2RvMZzKHKgmxy4uKBpreh4fX7f7XEEM8a9Nz8jGKF | 0.000 | |
| 522 | root | localhost:46444 | mysqlslap | Query | 4 | query end | INSERT INTO t1 VALUES (2101913295,1100418235,'XQ0K9x30cYaFq2RvMZzKHKgmxy4uKBpreh4fX7f7XEEM8a9Nz8jGKF | 0.000 | |
| 523 | root | localhost:46446 | mysqlslap | Query | 4 | query end | INSERT INTO t1 VALUES (1233983202,789373855,'jdtPbBILRQyiu7nZN3RdI96aQOP4Y0z7dlO4wbQF1OpvYdLnggGrqMP | 0.000 | |
| 524 | root | localhost:46448 | mysqlslap | Query | 4 | query end | INSERT INTO t1 VALUES (1233983202,789373855,'jdtPbBILRQyiu7nZN3RdI96aQOP4Y0z7dlO4wbQF1OpvYdLnggGrqMP | 0.000 | |
| 525 | root | localhost:46450 | mysqlslap | Query | 4 | query end | INSERT INTO t1 VALUES (1233983202,789373855,'jdtPbBILRQyiu7nZN3RdI96aQOP4Y0z7dlO4wbQF1OpvYdLnggGrqMP | 0.000 | |
| 526 | root | localhost:46452 | mysqlslap | Query | 4 | query end | INSERT INTO t1 VALUES (1233983202,789373855,'jdtPbBILRQyiu7nZN3RdI96aQOP4Y0z7dlO4wbQF1OpvYdLnggGrqMP | 0.000 | |
| 527 | root | localhost:46454 | mysqlslap | Query | 4 | query end | INSERT INTO t1 VALUES (1233983202,789373855,'jdtPbBILRQyiu7nZN3RdI96aQOP4Y0z7dlO4wbQF1OpvYdLnggGrqMP | 0.000 | |
| 528 | root | localhost:46456 | mysqlslap | Query | 4 | query end | INSERT INTO t1 VALUES (2101913295,1100418235,'XQ0K9x30cYaFq2RvMZzKHKgmxy4uKBpreh4fX7f7XEEM8a9Nz8jGKF | 0.000 | |
+-----+-------------+-----------------+-----------+---------+------+--------------------+------------------------------------------------------------------------------------------------------+----------+
|
}}
At this point, writing to any other node is also impossible, statements will hang, and so the whole cluster is locked.
FTWRL is used for backups, for example, so potentially a backup can lock the whole cluster.
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