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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10.2.21, 10.4.12
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CentOS/RHEL 7
Description
One of the customer reported that running a huge query (25KB) having a NOT-IN clause with many values running forever, causing the server to use available free memory and invoking the oom-killer to kill the mysqld process. Same behavior when tried to get the `EXPLAIN PLAN`.
Initially, checking the existing bugs, found following two:
MDEV-9764 - MariaDB does not limit memory used for range optimization
MDEV-9750 - extended_keys=on causing the memory exhaustion on queries having multiple IN/NOT IN using INNODB
As per those two bugs, we have told customer to turn off the "extended_keys" and check, but it's not helping out.
Further, locally on the MariaDB Server versions 10.2.21, 10.3.14 and 10.4.12(ES), I can reproduce the same behavior on an empty table. Here as well, neither setting "extended_keys=off" helped nor the "max_session_mem_used" system variable worked to avoid the exhaustion of available free memory.
Repro steps, I will share it separately.
Maybe, we need to understand how can we handle this case?
Thank You.
Attachments
Issue Links
- causes
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- Closed
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- includes
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- Closed
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- relates to
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MDEV-26856 Queries with many NOT IN clauses or ORs use a lot of memory
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- Open
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- Closed
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- Closed
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- mentioned in
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