Details
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Bug
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Status: Open (View Workflow)
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Major
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Resolution: Unresolved
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10.5.9
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None
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n.a.
Description
1. Docu here: https://mariadb.com/kb/en/aria-status-variables/
could be more clear that:
- Aria_pagecache_blocks_unused is the current state
- Aria_pagecache_blocks_used is a high water mark from somewhen in the past
2. Docu here: https://mariadb.com/kb/en/aria-status-variables/
and here: https://mariadb.com/kb/en/flush/#flush-status
states that this 3 status variables:
Aria_pagecache_blocks_not_flushed
Aria_pagecache_blocks_unused
Aria_pagecache_blocks_used
can be reset with flush status. This does IMHO technically not make sense (at least for not_flushed and unused, possibly it does make sense for the high water mark used) but experiments show that flush status does not reset the values:
root@mariadb-105 [test] SQL> show global status like 'aria%';
-----------------------------------------+
Variable_name | Value |
-----------------------------------------+
Aria_pagecache_blocks_not_flushed | 234 |
Aria_pagecache_blocks_unused | 15396 |
Aria_pagecache_blocks_used | 251 |
Aria_pagecache_read_requests | 102435 |
Aria_pagecache_reads | 50 |
Aria_pagecache_write_requests | 33141 |
Aria_pagecache_writes | 100 |
Aria_transaction_log_syncs | 20 |
-----------------------------------------+
8 rows in set (0.001 sec)
root@mariadb-105 [test] SQL> flush status;
Query OK, 0 rows affected (0.000 sec)
root@mariadb-105 [test] SQL> show global status like 'aria%';
-----------------------------------------+
Variable_name | Value |
-----------------------------------------+
Aria_pagecache_blocks_not_flushed | 202 |
Aria_pagecache_blocks_unused | 15396 |
Aria_pagecache_blocks_used | 251 |
Aria_pagecache_read_requests | 102435 |
Aria_pagecache_reads | 50 |
Aria_pagecache_write_requests | 33141 |
Aria_pagecache_writes | 132 |
Aria_transaction_log_syncs | 20 |
-----------------------------------------+
8 rows in set (0.001 sec)
root@mariadb-105 [test] SQL> flush tables;
Query OK, 0 rows affected (0.042 sec)
root@mariadb-105 [test] SQL> flush status;
Query OK, 0 rows affected (0.000 sec)
root@mariadb-105 [test] SQL> show global status like 'aria%';
-----------------------------------------+
Variable_name | Value |
-----------------------------------------+
Aria_pagecache_blocks_not_flushed | 0 |
Aria_pagecache_blocks_unused | 15647 |
Aria_pagecache_blocks_used | 251 |
Aria_pagecache_read_requests | 102435 |
Aria_pagecache_reads | 50 |
Aria_pagecache_write_requests | 33142 |
Aria_pagecache_writes | 335 |
Aria_transaction_log_syncs | 21 |
-----------------------------------------+
8 rows in set (0.001 sec)
This should be fixed or at least clarified...